simulation
MOPB025
Plasma based optics for electron beam fast micro-bunching
111
The utilization of plasma devices in beam transport is slowly being accepted as a worthy alternative thanks to its potential in maintaining or even reducing particle beams emittance but also for its compactness which supplements the recent advances in compact laser plasma acceleration systems. However, their use can go beyond the substitution of magnets. In this work, the utilization of a low density plasma device to micro-bunch electron beams through a "cascade focusing" caused by the beam generated wake inside the plasma. In addition, specialized particle in cell tools to study such phenomena over long distance (>cm) taking advantage of relativistic reference frames is swiftly presented. Such devices present a great potential for shortening future FEL facilities and increasing the efficiency of current.
Paper: MOPB025
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB025
About: Received: 29 May 2025 — Revised: 30 May 2025 — Accepted: 01 Jun 2025 — Issue date: 06 Jun 2025
MOPB034
Numerical simulation of on-axis helical undulator radiation using SCILAB-Xcos model
127
Abstract—A SCILAB Xcos model, developed using SCILAB software version 6.1.1, was implemented to simulate the on-axis radiation intensity of a helical undulator, (undulator parameter= 1, undulator wavelength 5cm, number of periods= 10, device length 0.6 m) with an electron beam (1, 2, & 3 GeV) and beam current as Ib = 3–6 × 10⁻⁶ Ampere. A numerical approach is utilized to perform the undulator radiation intensity calculations. The computed results were validated by comparing the on-axis undulator radiation intensity with those obtained from SPECTRA, an open-source synchrotron radiation (SR) calculation software.
Paper: MOPB034
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB034
About: Received: 13 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
MOPB040
Leveraging the capabilities of LCLS-II: linking adaptable photoinjector laser shaping to x-ray diagnostics through start-to-end simulation
143
SLAC’s LCLS-II is advancing towards MHz repetition rate attosecond X-ray pulses, creating opportunities to optimize X-ray generation through machine-driven controls and diagnostics via start-to-end simulation. Advanced laser shaping and upconversion techniques at the photoinjector, such as spatial light modulator-based pre-amplifier pulse shaping linked to nonlinear methods such as dispersion-controlled nonlinear synthesis or four-wave mixing, enable precise electron bunch control at the source. Downstream, diagnostics like the Multi-Resolution COokiebox (MRCO)—a 16-channel time-of-flight spectrometer—characterize X-ray pulse profiles, providing real-time feedback on attosecond X-ray pulses or attosecond X-ray substructure. We present developments towards a framework linking programmable photoinjector laser shaping to X-ray diagnostics, enabling data-driven optimization of the X-ray source. This approach combines machine learning, high-throughput feedback, and advanced control to align LCLS-II capabilities with experimental goals, laying the foundation for optimization of attosecond-scale precision in X-ray experiments.
Paper: MOPB040
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB040
About: Received: 30 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
MOPB058
SPS-II machine imperfections and optimization
173
SPS-II was designed for low emittance storage ring with compact Double-Triple Bend Achromat (DTBA) cell. To ensure sufficient machine performance, realistic machine imperfections were simulated and incorporated into the optimization process.Thus the lattice solutions were made robust against imperfections, thereby reducing the machine’s sensitivity. The solution with sufficient dynamic aperture and lifetime can be found in the presence of imperfections. The simulation steps and optimization will be discussed in this work.
Paper: MOPB058
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB058
About: Received: 26 May 2025 — Revised: 30 May 2025 — Accepted: 31 May 2025 — Issue date: 06 Jun 2025
MOPB071
Simulation study on fast beam-based alignment for commissioning of light sources
197
Beam based alignment (BBA) plays an important role in the commissioning of the light sources. To speed up the BBA, a BBA method using AC excitation, called fast BBA (FBBA), has been proposed and is tested in several existing light sources. In the FBBA, the beam orbit is sinusoidally modulated at around 10Hz by AC correctors, and the change in the beam response when a target quadrupole magnet strength is changed is measured using fast beam position monitors (BPM) at about 10kHz. To apply FBBA to light source commissioning, a simulation study of FBBA using random variables as response functions was performed to calculate the optimal corrector strength and variation of the strength of a quadrupole as a function of the BPM noise. We also improved the FBBA and found that a new FBBA scheme using two AC correctors of different frequencies separated by 1/2π betatron phase for one plane (horizontal or vertical) can suppress the BPM offset error by up to 10.
Paper: MOPB071
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB071
About: Received: 28 May 2025 — Revised: 01 Jun 2025 — Accepted: 01 Jun 2025 — Issue date: 06 Jun 2025
MOPB072
Magnet crosstalk in highly-compact light-source storage ring
201
Electron storage rings based on multi-bend achromat (MBA) lattice can achieve very low natural emittances. Several fourth generation light sources have been built and operating, the natural emittances of which are a few 100 pm or even lower than 100 pm, providing high brightness photon beams to users. Since the lattice of MBA storage ring tends to be highly compact, the field of a magnet may be affected by the neighboring magnets. This effect turned out to be significant in the new Swiss Light Source storage ring with 7-BA lattice during its design study: the integral fields of magnets are altered by a few percent due to the magnet cross talk at locations, which is an order of magnitude larger than the field precision typically required. We present how we managed to reproduce the design magnetic fields and optics including the cross talk effects
Paper: MOPB072
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB072
About: Received: 24 May 2025 — Revised: 30 May 2025 — Accepted: 31 May 2025 — Issue date: 06 Jun 2025
MOPB098
Simulation studies on optimization of hard and soft X-ray beamlines for parallel user service at the PAL-XFEL
228
PAL-XFEL (Pohang Accelerator Laboratory X-ray Free Electron Laser) is a facility that generates high-brightness FEL for users to perform the FEL-based sciences. Currently hard and soft X-ray (HX/SX) beamlines are operational, but the parallel operation can be done with less than 60 Hz using a single electron bunch from the electron injector. Therefore, for the user service with maximum repetition rate of 60 Hz on both HX and SX beamlines, a scheme that uses two bunches from the injector with an exact single cycle of 2.856 GHz frequency is under consideration. Particularly, simulation study is necessary to understand the optimal accelerator condition for both HX and SX since the SX shares the same accelerator condition up to the third accelerating column with the HX beamline. In this study, we show discussions using the particle tracking simulations showing the optimal conditions for both beamlines. We also present the potential issues to be considered in the actual operations such as error of RF cavity amplitude.
Paper: MOPB098
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB098
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
MOPB105
Simulation and optimization of a sub-THz Cherenkov FEL at AREAL
239
A circular waveguide lined with a thin dielectric layer enables electron bunches propagating within the structure to radiate light in the (sub-)THz regime. In this work, we perform simulations of low-energy electron beams traversing extended waveguides to analyze the dynamics of beam bunching and lasing within the structure. By exploring the free-electron laser (FEL) process in this context, we demonstrate the potential of waveguides as a cost-effective alternative to undulator-based FELs. The study employs a simulated model of the AREAL LINAC at the CANDLE SRI to demonstrate these effects and provide realistic results. The simulations are performed using the space charge tracking algorithm ASTRA and the wakefield solver ECHO. For optimization of the system, the genetic optimization algorithm GIOTTO is applied to refine both the waveguide and accelerator variables. Using a 4 MeV electron beam with a charge of 300 pC, the optimized setup achieves a radiation frequency of 100 GHz with energy outputs exceeding 20 µJ in a waveguide of only 1.2 meters length. These results underscore the feasibility of this method, offering a innovative pathway to produce intense THz radiation.
Paper: MOPB105
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB105
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
MOPB106
Optimizing Cherenkov waveguide seeding for THz SASE FELs towards stable, few-cycle pulses
243
The PITZ facility at DESY in Zeuthen has demonstrated the first operational high peak and average power THz self-amplified spontaneous emission (SASE) free electron laser (FEL). The current setup displays the onset of saturation at a central frequency of 3THz using a 3.5m long LCLS-I undulator. However, the THz user community has expressed the need for carrier-envelope phase (CEP) stability and the availability of few-cycle THz pulses to complement the currently demonstrated long pulses. In this work, simulations are conducted to evaluate and optimize FEL performance by incorporating a Cherenkov waveguide to seed the process. The waveguide parameter space is scanned to vary energy modulation depth and frequency, after which the performance is estimated using the space charge tracking algorithm, ASTRA, and the FEL simulation code, Genesis1.3. The optimized parameters allow saturation to be reached much earlier, while also significantly increasing the shot-to-shot stability. Down the line, the implementation of such a scheme would facilitate generation of few-cycle, CEP-stable THz pulses to be used in user experiments.
Paper: MOPB106
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB106
About: Received: 28 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
MOPB110
Research plans for the University of Hawai’i Accelerator and Free-Electron Laser Lab
250
The accelerator and free-electron laser (FEL) laboratory at the University of Hawai’i at Manoa (UHM), established by John Madey, has been in standby since his passing in 2016, with operations further paused during the pandemic. Recent efforts aim to recommission the facility, which includes a thermionic gun, an S-band linear accelerator reaching 45 MeV, and a Mark III undulator FEL oscillator producing tunable infrared light. Previously, 3 μm infrared light from this undulator demonstrated the capability to generate 10 keV X-ray photons via inverse Compton scattering. Current upgrades include enhancements to vacuum systems and linac controls. Future plans focus on enhancing cathode performance, developing 3D FEL simulations for superradiance studies, achieving phase coherence with interferometer optics, and using waveguides for THz generation. Recent GINGER simulations explored FEL oscillator output under varying Desynchronization conditions, demonstrating pulse train formation. The revived UHM accelerator will advance FEL science and train the next generation of researchers.
Paper: MOPB110
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB110
About: Received: 23 May 2025 — Revised: 02 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
MOPM003
Lattice correction and polarization estimation for the future circular collider e+e-
260
Precise determination of the center-of-mass energy at the Future Circular Collider (FCC-ee) operating at the Z and W resonance energies relies on resonant spin depolarization techniques, which require a sufficient level of transverse beam polarization in the presence of machine imperfections. In this study, the FCC-ee lattice is modeled and simulated under a range of realistic imperfections, complemented by refined orbit correction and tune-matching procedures. The equilibrium polarization is computed within these realistic machine models to investigate the causes of polarization loss and explore potential improvements through lattice optimization. Additionally, spin tune shifts, which contribute to systematic errors, are estimated to support the precision requirements of the energy calibration experiment.
Paper: MOPM003
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM003
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
MOPM005
Refining dynamic aperture calculations for highly damped accelerators: methods and applications to the FCC-ee
263
The dynamic aperture is a key metric for assessing the stable phase space of particle accelerators and evaluating their overall stability. However, in highly damped accelerators such as high-energy electron synchrotrons like the Future Circular Collider (FCC-ee), the rapid amplitude variation of tracked particles over a few turns introduces significant sensitivity to initial conditions and the particle's starting location. This work investigates these dependencies in the context of the FCC-ee and highlights their implications for stability analyses. We propose novel, more reliable methods to compute the dynamic aperture that account for these effects, improving the accuracy of stability predictions. First results from the application of these methods to the FCC-ee are presented, demonstrating their potential for advancing the understanding of beam dynamics in next-generation accelerators.
Paper: MOPM005
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM005
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
MOPM009
Optics tuning of the FCC-ee
275
The Future Circular Collider, FCC-ee, is a proposed next generation electron-positron collider aiming to provide large luminosities at beam energies from 45.6 up to 182.5 GeV. This collider faces a major challenge to deliver the design performance in the presence of realistic lattice errors. A commissioning strategy has been developed including dedicated optics designs, efficient beam-based alignment and optics corrections based on refined optics measurements. First specifications on main magnets, corrector circuits, and instrumentation have also been investigated. A summary of all these aspects is presented in this paper.
Paper: MOPM009
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM009
About: Received: 28 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
MOPM010
Emittance tuning of the FCC-ee high energy booster ring
279
The Future Circular Collider (FCC), in its leptonic configuration has been chosen by CERN as main proposition for the next high-energy collider. This project aims to achieve luminosities one to two orders of magnitude higher than ever. Feasibility studies have led to the definition of tolerances on magnet imperfections and correction strategies. This is crucial for ensuring the performance of one of the main elements of the acceleration chain, the High Energy Booster (HEB) ring. The efficiency and overall performance of these strategies greatly influence new magnet specifications and tolerances, affecting main optic functions. Horizontal and vertical orbit corrections use horizontal and vertical kickers, respectively. Skew quadrupoles address vertical dispersion and transverse coupling. Normal quadrupoles correct the horizontal and vertical phase advances. This study simulates the distribution of these four corrector types to minimize the equilibrium emittance at the extraction energy of 45.6 GeV. The calculated strengths of these correctors and the associated misalignments are presented. The study also discusses the limitations and drawbacks of the proposed correction strategy.
Paper: MOPM010
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM010
About: Received: 29 May 2025 — Revised: 02 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
MOPM011
Bayesian optimization for IP aberration correction and luminosity tuning in FCC-ee
283
FCC-ee luminosity optimization relies on measuring realistic signals from Bhabha scattering, beamstrahlung, and radiative Bhabha photons. Initial assessments of beamstrahlung signals examine the change in luminosity, beamstrahlung power and vertex detector hits in response to waist shifts, vertical dispersion and skew coupling at the collision point. These ongoing studies aim to extract IP-aberration-related signals from the energy spectrum, angular distribution, power of beamstrahlung photons, the vertex detector hits and the luminosity. Furthermore, the study integrates all these signals into a machine-learning-based approach for luminosity tuning and optimisation.
Paper: MOPM011
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM011
About: Received: 27 May 2025 — Revised: 02 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
MOPM013
Modelling resonant depolarisation
291
For the FCC-ee collider it is planned to, in regular intervals (minutes), measure the average beam energy of the circulating electron and positron beams with a relative precision of $10^{-6}$ or better, using the method of resonant depolarisation with pre-polarized pilot bunches. In this article, we study basic systematic effects and ultimate uncertainties that may arise in this kind of measurement. To do so, we carry out simulations for a simple model representing an ideal situation, where an ensemble of particles with energy spread is subjected to synchrotron oscillations and to perfect spin motion. We assume an initial spin orientation in the vertical direction for all particles. The behavior of the spin is explored as an exciter frequency is swept slowly or rapidly, and in either direction,through the spin resonance.
Paper: MOPM013
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM013
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
MOPM014
Overview of power deposition profiles in the LHC off-momentum cleaning section in Run 3
295
Off-momentum losses at the start of the LHC acceleration ramp in proton runs gave rise to multiple beam dumps by exceeding Beam Loss Monitor (BLM) thresholds in the momentum cleaning insertion (IR3). Accurately estimating the power deposition profiles in IR3 is necessary to determine where BLM thresholds can be optimized, thereby reducing unnecessary beam dumps and improving machine availability and performance. Understanding the loss limits in IR3 is crucial for future High-Luminosity LHC (HL-LHC) performance. In this study, we present FLUKA power deposition results and introduce a newly developed simulation model for BLM benchmarking in IR3. We provide a comprehensive overview of the power deposition in magnets and collimators, identifying potential bottlenecks in the system. Our simulations were benchmarked against multiple fills from 2023 and 2024 that led to beam dumps. The obtained results provide a deeper understanding of the IR3 collimation performance in view of HL-LHC operation in IR3.
Paper: MOPM014
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM014
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
MOPM015
Optimizing cavity detuning at high beam intensities in the LHC
299
The increased beam intensity during the high lumionsity LHC era is expected to impose tight margins on the operation of the LHC RF system. The larger momentum spread from the injectors together with twice the bunch charge requires a higher RF voltage at injection to avoid beam losses. However, the peak RF power due to the increased beam loading must be kept below the saturation level of the klystrons. Accurate optimization of RF parameters is therefore needed to maintain a sufficient RF voltage to capture and retain the injected beam. In the LHC, the beam-loading is partially compensated by detuning the RF cavities. This is achieved at injection by a pre-detuning scheme and throughout the injection plateau by applying half-detuning. During the 2024 run the pre-detuning was adjusted with beam to minimize the required peak power at injection. Furthermore, a new algorithm was developed to optimize the setup of the half-detuning scheme at a given bunch intensity. Both measures have been essential to accommodate higher beam intensities in the LHC.
Paper: MOPM015
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM015
About: Received: 27 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
MOPM018
Energy sensitivity of the High Luminosity LHC optics at the end of the Beta* squeeze
311
During 2022 and 2023 LHC optics commissioning, it was observed that at low-beta* small changes in the beam-energy could generate substantial perturbations of the linear beam optics, requiring re-commissioning of local corrections in the experimental insertions. This issue may become even more significant at the very low beta* anticipated for operation in the High Luminosity LHC (HL-LHC). Furthermore, energy drifts, for example due to the terrestrial tides, have generally been ignored during LHC optics commissioning, with no regular corrections applied during the duration of a specific measurement campaign. This paper examines the anticipated sensitivity of HL-LHC optics corrections to energy errors at end of the beta* squeeze.
Paper: MOPM018
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM018
About: Received: 27 May 2025 — Revised: 30 May 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
MOPM019
Correction of Long-Range Beam-Beam Driven Normal Sextupolar Resonance Driving Terms
315
Beam-based studies at the LHC injection energy showed that compensation of the strongly driven sextupolar resonance, Qx+2Qy, improved both the dynamic aperture and lifetime of the beam, even when far from the working point and on the far side of the 3Qy resonance. Thus, a reduction of other strong normal sextupolar resonance sources was of interest. In 2024, the first measurements of resonance driving terms with long-range beam-beam (LRBB) interactions were performed. These showed that LRBB was driving the same Qx+2Qy resonance strongly when colliding, in agreement with model predictions. A correction was found for the strongest normal sextupole resonances using the existing sextupole corrector magnets in the LHC, obeying the constraints on the chromatic coupling and the maximum magnet powering. Beam-based tests to validate the response of this correction with non-colliding beams have been performed along with the testing of the LRBB resonance correction during LHC commissioning.
Paper: MOPM019
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM019
About: Received: 23 May 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
MOPM020
Investigation of octupolar resonances in the LHC
319
During operation for luminosity production, the LHC runs with very strong Landau octupoles to ensure the collective stability of the beams. A disadvantage of this is that these octupoles can drive resonances which can be detrimental to beam lifetime. Recently, a special optics configuration has been utilised to reduce the impact of the main octupoles on lifetime. This design relies on correctly modelling the resonance driving term (RDT) response to changes in these magnetic circuits. This paper presents beam-based studies comparing the RDT response to simulations where large discrepancies were found. To try and understand the source of this, several approaches were taken. Various methods including individual circuit measurements, studies of other circuits, and tests at different energy were employed but it remained challenging to localise the source of the discrepancy around the ring. This paper presents an attempt to apply and extend a segment-by-segment method, that has been very effective at identifying local linear optics errors, to non-linear errors through analysis of RDTs.
Paper: MOPM020
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM020
About: Received: 27 May 2025 — Revised: 30 May 2025 — Accepted: 01 Jun 2025 — Issue date: 06 Jun 2025
MOPM021
Proof-of-principle experiment to reconstruct the trajectory of dust grains interacting with the LHC beams
323
Interactions of dust grains with the LHC beams cause beam losses that can trigger premature beam aborts or even quenches of superconducting dipoles. While the simulated motion and ionisation of dust grains inside the proton beam are in good agreement with measured beam-loss data, a direct measurement of the dust movement is not available. A novel method was developed that reconstructs the trajectory of a dust grain based on the different beam loss profiles of transversely displaced bunches. A proof-of-principle experiment to validate the method using a thin wire to simulate the dust grain was performed in June 2024 at the LHC. This paper describes the beam experiment, compares the achieved displacements with simulations, and shows the reconstructed trajectories. Finally, it is discussed how the method can be applied for real dust events occurring during LHC operation.
Paper: MOPM021
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM021
About: Received: 28 May 2025 — Revised: 01 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
MOPM023
Damage potential and machine protection criticality of the FCC-ee beams
331
The lepton beams of the Future Circular Collider FCC-ee will store 17.5 MJ of energy per beam during Z mode operation. The damage potential of these beams is an essential input for the design of the machine protection system. In this paper, first, the stored energy and energy density of the FCC-ee beams are reported and compared with the values for the Large Hadron Collider (LHC) and the High-Luminosity LHC (HL-LHC). Then, results of energy deposition studies using FLUKA for the generic scenario of a direct beam impact on graphite are presented. Due to the small beam sizes and the distinct shower development, the FCC-ee beams cause peak energy depositions that for Z mode intensities can be comparable to the LHC proton beams. In a last step, the initial hydrodynamic response of the material is simulated using ANSYS Autodyn for a round beam featuring an equivalent peak energy deposition. The calculated temperature rise and density depletion are presented and discussed.
Paper: MOPM023
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM023
About: Received: 28 May 2025 — Revised: 30 May 2025 — Accepted: 30 May 2025 — Issue date: 06 Jun 2025
MOPM027
Impact of ground motion on FCC-ee performance
347
The Future Circular Collider for electron-positron collisions (FCC-ee) is a proposed next-generation particle accelerator aimed at achieving high luminosity and precision for fundamental particle physics experiments. Its performance is sensitive to environmental factors such as ground motion, which can induce vibrations and misalignments in critical accelerator components. This paper presents a detailed study on the impact of ground motion on FCC-ee performance, with a focus on beam stability, alignment tolerances, and the complex interplay between ground motion and operational parameters. Using advanced simulations and analytical modeling, we evaluate the FCC-ee's sensitivity to various ground motion scenarios, ranging from localized, uncorrelated disturbances to correlated plane waves, and analyze their effects on the beam optics, orbit distortions, and overall beam dynamics. The findings provide valuable insights into the design and operational strategies required to mitigate ground motion effects, guiding future research and engineering efforts to ensure the successful realization of the FCC-ee project.
Paper: MOPM027
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM027
About: Received: 27 May 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
MOPM032
Simulations of losses from fast instabilities in the FCC-ee
367
The electron-positron Future Circular Collider (FCC-ee) is a proposed high-energy lepton collider that aims to reach unprecedented luminosity and precision in the measurement of fundamental particles. To fully profit of such performance, it is crucial to keep detector backgrounds under control and operate the machine safely. Due to the high stored beam energy and to a number of complex operational features required at FCC-ee (e.g. the top-up injection scheme), controlling the backgrounds to the physics experiments becomes even more challenging. Recent studies on collective effects have shown that high impedance in the FCC-ee can lead to fast rise-time instabilities, where the beam amplitude grows exponentially, leading to beam loss within a few turns. Although a feedback system is being developed to mitigate this instability, failure scenarios of this feedback system need to be explored. This paper presents the study of the effects of this instability, in order to understand the possible implications for the machine and the experiments.
Paper: MOPM032
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM032
About: Received: 21 May 2025 — Revised: 30 May 2025 — Accepted: 01 Jun 2025 — Issue date: 06 Jun 2025
MOPM033
Coherent plane ground wave impact on the FCC-ee beam centroid
371
The FCC-ee is a collider, proposed after the LHC era, based on a ring of approximately 90 km of circumference. It will have to be able to accommodate beams running at half the z-pole and tt ̅-pole with vertical Interaction point beam size less than 40 nanometer at the z. In the present studies, coherent ground motions are being explored with particle tracking tools such as MAD-X and analytics code. The effect of parameters, such as harmonics, phase, orientation, defining global vertical sine waves like motion, are hence being detailed. At the time of writing, several lattices are subject to investigations. The differences in term of beam centroid for the main lattices and energy running will also be exposed. The impact of these motions of the machine detector interface quadrupoles is discussed.
Paper: MOPM033
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM033
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
MOPM035
Comparison of Xsuite simulations with measured backgrounds at SuperKEKB
379
Xsuite is a collection of packages developed to simulate beam dynamics in particle accelerators. It includes Python modules (Xobjects, Xpart, Xtrack, Xcoll, Xfields, Xdeps) that can be seamlessly integrated with one another and with both accelerator-specific and general-purpose Python tools, enabling the study of complex simulation scenarios. The Xcoll module, developed for collimation studies, allows the integration of beam-matter interaction simulations in the tracking through different available scattering models, including those in the BDSIM/Geant4 toolkit. Originally developed for the Future Circular e+e- Collider (FCC-ee) collimation simulation needs, the Xsuite-BDSIM/Geant4 interface is now deployed in full production for FCC-ee collimation studies. A key aspect of such studies relying on complex simulations is their benchmarking against measured data. This paper presents a first comparison of Xsuite collimation simulation results with measured data at the SuperKEKB e+e- collider.
Paper: MOPM035
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM035
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
MOPM036
Beam losses due to beam-residual gas interactions in the FCC-ee
383
The Future Circular electron-positron Collider, FCC-ee, is a design study for a luminosity-frontier and highest-energy e+e- collider with a 91 km circumference. In a circular machine, the interactions between the beam particles and the residual gas in the vacuum chamber may degrade the beam quality, potentially affecting the beam lifetime and the collider luminosity, and cause local beam losses. In addition, experimental backgrounds may be increased. Ideally, the vacuum system must be able to keep vacuum conditions sufficiently good so that beam-residual gas interaction effects are tolerable for collider operation. This paper presents a study of the beam loss distribution arising from beam-residual gas interactions in the FCC-ee, together with beam-gas lifetime estimates.
Paper: MOPM036
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM036
About: Received: 28 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
MOPM037
FCC-ee optics tuning studies with pyAT and Xsuite
387
The FCC-ee is a future high-luminosity circular electron-positron collider aiming at achieving unprecedented luminosities with beam energies ranging from 45.6 up to 182.5 GeV. FCC-ee demands precise optics tuning to achieve its ambitious performance goals. This study investigates the tuning and correction of FCC-ee optics under simulated magnet misalignments, with a particular focus on the stringent initial alignment tolerances required in the Interaction Region (IR). Random misalignment errors were introduced, and correction algorithms were applied to recover the nominal lattice configuration using the pyAT optics framework. Post-correction dynamic aperture studies were conducted to assess the stability and resilience of the lattice under realistic operational scenarios. Benchmarking pyAT outcomes against the Xsuite framework validated the reliability and consistency of the corrections. The study offers valuable insights into alignment tolerance limits, correction methodologies, and their implications for beam dynamics, providing essential guidance for the development and operation of the FCC-ee.
Paper: MOPM037
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM037
About: Received: 27 May 2025 — Revised: 02 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
MOPM038
FCC-ee Interaction point optics correction with alignment errors using local tuning knobs
391
Optics tuning and correction in the Interaction Point (IP) region of the FCC-ee is critical for achieving the target luminosity. By utilizing dedicated IP tuning knobs, lattice errors at multiple IP's are corrected to restore the design optics, enabling dynamic aperture studies on the fully corrected lattice. These studies, conducted using the pyAT optics code, assess the impact of corrections and the effectiveness of various tuning knobs in mitigating beam size growth at the IP's while maintaining beam stability. Benchmarking of pyAT results with the Xsuite framework ensures the reliability and robustness of the analysis. This approach provides valuable insights into the precision of IP optics tuning and its role in optimizing the collider's operational performance.
Paper: MOPM038
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM038
About: Received: 27 May 2025 — Revised: 02 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
MOPM039
Updated monochromatization Interaction Region optics design for FCC-ee GHC lattice
395
Determining Yukawa couplings of the Higgs boson is one of the most fundamental and outstanding measurements since its discovery. The FCC-ee, owing to its exceptionally high-integrated luminosity, offers the unique opportunity to measure the electron Yukawa coupling through s-channel Higgs production at 125 GeV centre-of-mass (CM) energy, provided that the CM energy spread can be reduced from 50 MeV to a level comparable to the Higgs bosons’ natural width of 4.1 MeV. To improve the energy resolution and reach the desired collision energy spread, the concept of a monochromatization mode has been proposed as a new operation mode at the FCC-ee, relying on the Interaction Region (IR) optics design with a nonzero dispersion function of opposite signs at the interaction point (IP). A first optics design and preliminary beam dynamics simulations have been carried out for version 22 of the FCC-ee GHC lattice type. In response to the continuously evolving FCC-ee GHC optics, this paper presents an optimized updated monochromatization IR optics design based on the Version 2023 of the FCC-ee GHC optics.
Paper: MOPM039
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM039
About: Received: 28 May 2025 — Revised: 05 Jun 2025 — Accepted: 06 Jun 2025 — Issue date: 06 Jun 2025
MOPM040
Optimized physics performance evaluation of monochromatization interaction region optics for direct s-channel Higgs production at FCC-ee
399
The measurement of electron Yukawa coupling ($y_{e}$) via direct *s*-channel Higgs production at $\sim$125 GeV centre-of-mass (CM) energy is significantly facilitated at the FCC-ee, provided that the CM energy spread can be reduced to a level comparable to the natural width of the Higgs boson. This reduction is possible through the “monochromatization” concept, which involves generating opposite correlations between spatial position and energy deviation in the colliding beams. Following initial parametric studies for this collision mode, three different interaction region optics designs, each featuring nonzero horizontal, vertical, or combined dispersion at the interaction point, have been proposed based on the Version 2022 of the FCC-ee Global Hybrid Correction optics. In this paper, we benchmark the upper limits contours on $y_{e}$ with simulated CM energy spread and luminosity using Guinea-Pig, in order to assess, optimize, and compare their physics performances.
Paper: MOPM040
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM040
About: Received: 28 May 2025 — Revised: 06 Jun 2025 — Accepted: 06 Jun 2025 — Issue date: 06 Jun 2025
MOPM041
Estimation of FCC-ee beam lifetime from full lattice tracking
403
Across its energy range, the beam lifetime at the Future Circular Collider $e^+e^-$ (FCC-ee) will be dominated by radiative processes occurring as a result of the beam-beam collision, namely by beamstrahlung and small angle radiative Bhabha scattering. Although approximate analytical expressions exist for estimating the lifetime, it is most accurately evaluated by performing multiparticle tracking simulations, due to the interplay of magnetic errors with non-linear forces due to the beam-beam interaction. This contribution presents the first comprehensive study of the FCC-ee beam lifetime including both effects, simulated with the Xsuite framework.
Paper: MOPM041
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM041
About: Received: 24 May 2025 — Revised: 02 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
MOPM043
Comparison of particle in cell and soft-Gaussian beam-beam solvers
407
A crucial component for designing particle colliders is the assessment of beam-beam effects at collisions. Particle In Cell (PIC) solvers are popular numerical tools, which solve the Poisson equation for the electromagnetic (EM) potential $\Phi$ produced by the colliding beam's bunches spread on a discretized grid, and compute the Lorentz force acting on the particles subjected to the gradient of $\Phi$. The main limitation of this approach is the high computational cost, which can be alleviated at the expense of accuracy by using approximation techniques, such as the soft-Gaussian approximation, which assumes the bunch particles to have transverse Gaussian distributions. Both methods are widely used in the accelerator physics community. The Xsuite framework is the first multiparticle tracking tool, which aims to support both approaches. This contribution compares the performance of their Xsuite implementation.
Paper: MOPM043
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM043
About: Received: 24 May 2025 — Revised: 02 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
MOPM048
Study of the coherent < x-z > instabilities for FCC-ee
426
This work examines the dominant coherent head-tail type (< x-z >) instabilities in the vertical plane of the FCC-ee collider, focusing on a mode analysis method with the Circulant Matrix Model (CMM) to assess instability mechanisms under the influence of beam-beam effects and transverse wakefields. While the impact of vertical plane instabilities have been already studied, different mechanisms are prominent in the horizontal plane. Understanding these mechanisms is crucial to identifying a stable working point at the Z energy. This study aims to advance the stability analysis and optimisation of FCC-ee at Z energy by investigating horizontal plane dynamics. Our findings indicate that mitigation strategies effective for vertical plane instabilities may not be sufficient and need to be adapted in order to ensure overall beam stability.
Paper: MOPM048
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM048
About: Received: 26 May 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
MOPM049
Longitudinal wakefield implementation in the circulant matrix model
430
The influence of longitudinal wakefields on the beam dynamics in electron-positron colliders, particularly their role in beam instabilities such as Transverse Mode Coupling Instability (TMCI) and other transverse-longitudinal effects, necessitates a robust approach to accurately model these effects. This work focuses on the implementation of wakefield effects in the Circulant Matrix Model (CMM), a linear model that can facilitate the representation of these instabilities. We study the impact of potential well distortion and synchrotron frequency shifts due to longitudinal wakefields for FCC-ee and implement these effects in the CMM. The implementation is benchmarked against reference multiparticle tracking simulations to validate its accuracy in predicting longitudinal wakefield-driven instabilities. Results enable further studies featuring longitudinal wakefields for collider designs and operating machines.
Paper: MOPM049
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM049
About: Received: 26 May 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
MOPM050
Combining quadrupole-driven slow extraction with RFKO at the CERN SPS
434
The CERN Super Proton Synchrotron (SPS) employs quadrupole-driven third-integer slow extraction to deliver beam to the North Area. This process is controlled by ramping all the magnets in the lattice, gradually driving the circulating beam into the tune resonance. In medical synchrotrons, Radio-Frequency Knock Out (RFKO) has proven to be a reliable alternative for driving the extraction process while maintaining good spill quality. Inspired by these efforts, a hybrid scheme was tested in the SPS, where a transverse exciter was used to apply a sinusoidal excitation in parallel with the magnetic ramp. It is demonstrated that this setup improves spill uniformity both in simulation and measurements.
Paper: MOPM050
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM050
About: Received: 26 May 2025 — Revised: 30 May 2025 — Accepted: 01 Jun 2025 — Issue date: 06 Jun 2025
MOPM052
Bayesian methods and differentiable models for optics studies at the ISOLDE facility
442
The Isotope mass Separator On-Line facility (ISOLDE) delivers a wide range of low-energy radioactive ion beams to its experimental users. To meet varying demands, the facility uses different target materials, ionization methods, and cooling/bunching techniques, with beam configurations potentially changing weekly. To model particle transport through the transfer lines, it is essential to reconstruct the beam's initial transverse phase space for each setup, achieved via quadrupole scan measurements. This work explores the application of Bayesian techniques and differentiable models to reduce the time required to perform the beam setup.
Paper: MOPM052
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM052
About: Received: 26 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
MOPM058
Beam tracking simulation of the capture LINAC for the ILC e-driven positron source
446
In the electron-driven positron source of the International Linear Collider (ILC), positrons are generated through electromagnetic showers by irradiating a target with a 3 GeV electron beam and then accelerated in a positron capture linac in a solenoid magnetic field. Because of the high current multi-bunch beam requirements of ILC, the beam loading effect is one of the important issues. In order to identify engineering issues, a test bench has been set up at the KEK-STF to build and test prototypes of a target system, a flux concentrator, an accelerating tube and a solenoid coil. Based on this test bench arrangement, a beam tracking simulation of the positron source from target to the upstream of the capture linac has been started by PIC simulation using the commercial code CST studio. In this contribution, the results of beam tracking simulation with the realistic magnetic field, accelerating field and placements of components and the effects of beam loading on beam energy and yield will be reported.
Paper: MOPM058
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM058
About: Received: 27 May 2025 — Revised: 30 May 2025 — Accepted: 30 May 2025 — Issue date: 06 Jun 2025
MOPM060
CETASim: a numerical tool for beam collective effect study in storage rings
449
We developed a 6D multi-particle tracking program CETASim in C++ to simulate intensity-dependent effects in electron storage rings. The program can simulate the beam collective effects due to short-range/long-range wakefields for single/coupled-bunch instability studies. It also features the simulation of interactions among charged ions and the trains of electron bunches, including both fast ion and ion trapping effects. The bunch-by-bunch feedback is also included so that the user can simulate the damping of the unstable motion when its growth rate is faster than the radiation damping rate. The particle dynamics is based on the transfer maps from sector to sector, including the nonlinear effects of amplitude-dependent tune shift, high-order chromaticity, and second-order momentum compaction factor. Users can also introduce a skew quadrupole useful for emittance sharing and exchange studies. This paper briefly introduces the code structure and gives benchmark studies for single and coupled bunch effects. PETRA-IV H6BA lattice parameters are applied as test-bed.
Paper: MOPM060
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM060
About: Received: 28 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
MOPM061
Study of single bunch effect in PETRA-IV storage ring
452
The H6BA lattice is now considered as the baseline design for PETRA-IV light source. It is required that the ring can be operated with and without damping wigglers, resulting in two sets of natural equilibrium beam parameters. This paper analyzes the single-bunch effects due to impedance in the H6BA lattice of PETRA-IV. We will show the influence of the impedance on the electron beam in both scenarios, with and without DWs. With the help of a 3rd harmonic cavity and a high chromaticity of 6 units, the single bunch current threshold exceeds 2 mA, leaving a 100% safety margin. At the nominal coupling of 0.1, the Touschek lifetime is larger than 10 hours in all operational scenarios.
Paper: MOPM061
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM061
About: Received: 28 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
MOPM067
Radiation load from radiative Bhabha scattering in the FCC-ee experimental insertions
471
The lepton Future Circular Collider (FCC-ee) at CERN provides electron-positron collisions at four interaction points (IPs) along a 91 km ring, with beam energies spanning from 45.6 GeV (Z pole) to 182.5 GeV (ttbar threshold). The radiation showers produced by these collisions can reach sensitive components of the surrounding machine elements, possibly affecting their performance and lifetime. This contribution examines the case of radiative Bhabha scattering, which generates off-momentum beam particles that can be lost downstream. Some losses occur already at the superconducting final focusing quadrupoles (FFQs), where they can cause quenches and degradation of the coil materials. In this work, the Monte Carlo code FLUKA is used to study the impact of radiative Bhabha in the experimental insertion regions of FCC-ee. The radiation load in the FFQs and the radiation levels in the nearby tunnel and machine elements are simulated for the Z-pole and ttbar operational modes. For the FFQs, a tungsten shielding layer with optimized thickness is proposed to mitigate the radiation load in the magnet coils.
Paper: MOPM067
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM067
About: Received: 28 May 2025 — Revised: 30 May 2025 — Accepted: 30 May 2025 — Issue date: 06 Jun 2025
MOPM069
Power deposition studies for the FCC-ee halo collimation system
475
The Future Circular Collider (FCC-ee) at CERN requires a betatron and momentum collimation system for reducing particle backgrounds in the detectors, and for protecting the machine in case of excessive beam losses. The system is composed of primary and secondary collimators, which will be housed in one of the technical insertions of the 91 km ring. In this paper, we present a first assessment of the beam-induced power deposition in the collimators using FLUKA Monte Carlo simulations. We show that dedicated shower absorbers are needed in the collimation insertion, which intercept secondary particles from the halo collimators and reduce the energy leakage to the environment. A first optimization of the shower absorber configuration is presented, considering different absorber positions and absorber lengths. We demonstrate that the power absorption of the betatron collimation system can be increased from about 50% to over 80% by adding two shower absorbers between primary and secondary collimators.
Paper: MOPM069
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM069
About: Received: 27 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
MOPM077
Commissioning of the new FLASHlab@PITZ beamline extension
487
Over the past year a new beamline dedicated to R&D for electron FLASH cancer radiation therapy and radiation biology was set up at the Photo Injector Test facility at DESY in Zeuthen (PITZ). The beamline runs in parallel to the SASE THz beamline at PITZ and is connected to it with an achromatic dogleg. The dispersion within the dogleg is utilized to install an aperture to scrape off-energy dark current. The following straight section of the beamline contains a kicker system which will be capable of distributing electron bunches from a single bunch train freely over an area of 25mm x 25mm within one millisecond. So far, only the slow kicker for the vertical plane is installed – the fast kicker for the horizontal plane will be installed soon. Behind an exit window is an experimental area for conducting irradiation experiments with the 22 MeV electron beam, which can accommodate setups for a wide range of experiments. Here we report the completion of the construction of the new beamline with detailed information about the setup. Preparation results of the PITZ robot and further data of the new experimental area are described. Additionally some new simulation results are given.
Paper: MOPM077
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM077
About: Received: 26 May 2025 — Revised: 31 May 2025 — Accepted: 31 May 2025 — Issue date: 06 Jun 2025
MOPM080
Optimisation of drift tube cooling and drift tube geometries of an additive manufacturing IH-type cavity
499
Additive manufacturing is a now-powerful tool for the rapid prototyping and manufacturing of complex geometries. A proof-of-concept 433 MHz IH-DTL cavity was constructed for direct additive manufacturing of linear accelerator components. The CFD analysis of the initially designed cooling for the drift tube revealed a design with insufficient heat dissipation; this can lead to thermal deformations as well as problems in keeping the frequency stable during operation. In this respect, an optimization of the cooling system was done in detail with the help of advanced thermal simulation and iterative design improvements. Furthermore, the geometries of the drift tubes were refined to improve mechanical stability and thermal efficiency without compromising electromagnetic performance. The results illustrate that additive manufacturing can achieve significant design freedom, enabling new approaches toward the thermal management challenges faced by high-frequency linear accelerator components.
Paper: MOPM080
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM080
About: Received: 28 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
MOPM092
Machine learning approach to MDI optimization for 3 TeV c.o.m. Muon Collider
528
The Muon Collider is a proposed future accelerator for very high energy muon collision. Since muons are heavier than electrons, the synchrotron radiation is negligible at this high energy, allowing to build a compact machine able to deliver Multi-TeV c.o.m. energy collisions, enabling precision measurements of the Standard Model quantities and search for new physics. A challenge of a muon beam is the Beam-Induced Background (BIB), a flux of particles in the detector generated by secondary interaction of muon decay products with the accelerator components. To deliver the required physics performance, the Machine Detector Interface design needs to include a shielding for the BIB. The proposed solution consists of cone-shaped tungsten shields inside the detector area. The nozzles reduce the BIB to a manageable level at the cost of reducing the detector acceptance. A careful optimization of the geometry is necessary to further mitigate the BIB and improving the detector acceptance to maximize the physics potential. This contribution aims at discussing the optimization achieved with machine learning algorithms in combination with FLUKA simulations for a 3 TeV c.o.m. Muon Collider.
Paper: MOPM092
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM092
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
MOPM093
Positron contamination in the muon beam at the J-PARC's surface muon beamline (S-line)
531
The surface muon beamline at J-PARC provides high-intensity muon beams that are essential for advanced materials science research, particularly in techniques such as muon spin rotation/relaxation (μSR). However, positron contamination in the beam poses a significant challenge by introducing background noise that affects the measurement precision. Therefore, achieving high-purity muon beams is critical for improving experimental reliability and accuracy. In this study, the G4beamline Monte Carlo simulation toolkit was employed to model the transport of muons and positrons from the production target through the beamline. The system includes a momentum and charge-based separator followed by a collimating slit. While the current slit configuration effectively suppresses positrons, it also causes substantial muon loss of approximately 76%, which significantly reduces the usable muon flux for downstream applications. To address this issue, a detailed investigation into slit size was performed. The results indicate that modest adjustments to the slit aperture size can improve the muon-to-positron ratio while retaining a greater fraction of the muon beam. These results provide valuable guidance for optimizing beamline performance and improving the quality of muon-based experiments at J-PARC.
Paper: MOPM093
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM093
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
MOPM100
Benchmarking the LHC impedance model through loss of Landau damping measurements and simulations
538
Refining the present longitudinal impedance model is essential for an accurate prediction of beam stability thresholds. Longitudinal loss of Landau damping (LLD) for single bunches were observed in the Large Hadron Collider (LHC). For High Luminosity (HL-) LHC beams, the present stability margin is aimed to be maintained. While coupled-bunched instability has not been detected in the LHC so far, it may become an issue at HL-LHC parameters. Recent studies have shown that broad-band impedance contributions and their cut-off frequencies affect the LLD threshold. In this contribution, results from the analysis of the machine development studies of 2024 are presented and compared to macroparticle tracking simulations, as well as LLD threshold predictions using semi-analytical solvers. Their discrepancies are discussed, and potential sources are investigated.
Paper: MOPM100
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM100
About: Received: 16 May 2025 — Revised: 30 May 2025 — Accepted: 30 May 2025 — Issue date: 06 Jun 2025
MOPS011
Improvement on beam-based alignment methods by reliability weighted average technique
593
Accurate determination of magnet centres seen by beams is the key to a successful commissioning of a particle accelerator storage ring. In this paper, several techniques to improve the beam-based alignment for a circular accelerator storage ring are introduced. Firstly, a formula to propagate the uncertainties from linear fitting is given. Secondly, a reliability weighted averaging technique based on uncertainties are applied to mitigate the impact of outliers. Thirdly, studies show that the accuracy and precision of quadrupole centre locations can be refined by using multiple corrector magnets in the process. Finally, to improve the efficiency when using multiple correctors, a monte-carlo technique is utilized. The resulting distributions of all BPM-to-Quad offset residuals derived from simulations are presented.
Paper: MOPS011
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS011
About: Received: 27 May 2025 — Revised: 31 May 2025 — Accepted: 01 Jun 2025 — Issue date: 06 Jun 2025
MOPS015
Exploring the null space of the chromaticity response matrix at the Diamond Light Source
601
Many different techniques have been investigated at Diamond for optimising sextupole strengths*. One method not previously studied is to exploit the null space of the chromaticity response matrix. By performing a singular value decomposition (SVD) of the chromaticity response matrix, combinations of sextupole strengths are identified which alter the nonlinear lattice whilst keeping the chromaticity unchanged. Applying these sextupole strength changes opens an avenue to improve the beam lifetime and the injection efficiency at fixed chromaticity, thereby preserving the instability thresholds from collective effects. The results of applying this technique are presented both for beam tracking simulations for the Diamond-II lattice, including machine errors, and for machine-based measurements on the present Diamond synchrotron.
Paper: MOPS015
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS015
About: Received: 28 May 2025 — Revised: 30 May 2025 — Accepted: 01 Jun 2025 — Issue date: 06 Jun 2025
MOPS016
Multi-objective optimisation of the Diamond-II storage ring optics
605
The design performance of the 3.5 GeV Diamond-II low-emittance electron storage ring has been studied as a function of the linear and nonlinear lattice tuning parameters. A Multi-Objective Genetic Algorithm (MOGA) has been implemented to optimise both the beam lifetime and the injection efficiency for off-axis injection. The simulations have been run on 5 machine error seeds, including misalignment and field strength errors, to obtain a solution which is robust against machine imperfections. The results of the optimisation are presented alongside a comparison of the baseline performance.
Paper: MOPS016
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS016
About: Received: 28 May 2025 — Revised: 30 May 2025 — Accepted: 01 Jun 2025 — Issue date: 06 Jun 2025
MOPS017
Further progress with alternative optics for the Diamond-II storage ring upgrade
609
We report the progress made on alternative optics namely low beta and low emittance cases for the DIAMOND-II storage ring upgrade. The results of optimizations of both linear and nonlinear optics as well as impacts of insertion devices on lifetime and dynamic aperture and injection scenarios will be reported.
Paper: MOPS017
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS017
About: Received: 23 May 2025 — Revised: 30 May 2025 — Accepted: 01 Jun 2025 — Issue date: 06 Jun 2025
MOPS019
Simulated beam performance of the TWOCRYST proof of principle experiment at the LHC
617
TWOCRYST is a machine test designed to demonstrate the feasibility of an in-vacuum fixed-target experiment for the first direct measurement of the magnetic and electric dipole moments of short-lived charm baryons. This setup exploits crystal channeling using two bent crystals. The first one is similar to the existing crystals used in the LHC for beam collimation, deflecting the beam halo particles from the proton beam onto a target. The second one - a 7 cm silicon crystal - induces spin precession in the secondary particles produced in the target. 2D detectors in movable Roman pots will track the distribution of these channeled particles. A new silicon pixel detector and a fiber tracker (formerly used by the LHC ATLAS-ALFA experiment) are planned for installation in the LHC along with the two crystals in early 2025. Xsuite simulations have been performed to reproduce the multi-turn beam dynamics of the channeled beam halo and the particle distribution expected at the detectors. The LHC configurations required for the planned measurements have also been simulated, with the results used to specify the required detector performance in preparation for benchmarking against real data.
Paper: MOPS019
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS019
About: Received: 20 May 2025 — Revised: 30 May 2025 — Accepted: 30 May 2025 — Issue date: 06 Jun 2025
MOPS020
The TWOCRYST fibre tracker: A detector to characterize precession crystals at the LHC
621
A fixed-target experiment using two bent crystals is proposed to study the magnetic and electric dipole moments of short-lived charm baryons with unprecedented precision in the LHC. This will be achieved exploiting crystal channeling into a first crystal to extract the beam halo and then into a 7 cm long silicon crystal capable of inducing a measurable spin precession to the particles of interest. TWOCRYST is a proof-of-principle machine test scheduled for 2025, to test this setup and address the feasibility of the final experiment under LHC beam conditions. One main goal is the study of the channeling efficiency in this long crystal at TeV energies, requiring a 2D detector in movable Roman pots. The TWOCRYST Fibre Tracker, coming from the LHC's ATLAS-ALFA experiment, is a high-precision tracking detector with ten layers of crossing scintillating fibers coupled to multi-anode photomultipliers, and read out using compact front-end electronics. Intense refurbishment work was required on to adapt the detector to the purposes of TWOCRYST. This contribution summarizes the tracker specifications as derived from beam dynamics simulations and the results of tests prior to its installation.
Paper: MOPS020
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS020
About: Received: 20 May 2025 — Revised: 30 May 2025 — Accepted: 30 May 2025 — Issue date: 06 Jun 2025
MOPS022
Investigation on injection-related beam loss at SuperKEKB
625
The current achieved highest luminosity at SuperKEKB is only one-tenth of the design value, and beam injection is one of the most serious issues in achieving the target luminosity. Recent operations in both the HER and LER rings have shown insufficient injection efficiencies and detector backgrounds. The achieved injection efficiency falls short of the required level, sometimes leading to difficulties in injecting the beam at high current values. Following each injection, significant signals from particle losses are detected in several Belle II detector components, particularly the vertex detector, resulting in saturating the data acquisition with a dead time exceeding 10ms. The complexity of the injection, and critical factors like injected beam quality, beam lifetime, dynamic aperture, machine errors, nonlinearity, as well as the collimation system, makes the optimization challenging. Detailed injection simulations are essential to understand the issues of the injection and guide adjustments to maximize the injection efficiency and mitigate the injection background. This paper presents the findings of HER injection simulations and their experimental validation.
Paper: MOPS022
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS022
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 06 Jun 2025 — Issue date: 06 Jun 2025
MOPS024
Implementation and simulation of a rectilinear cooling channel in BDSIM
633
Muon colliders offer high-luminosity, multi-TeV collisions without significant synchrotron radiation but require further exploration of muon production, acceleration, cooling, and storage techniques. A proposed 6D cooling demonstrator aims to extend the MICE experiment's validation of transverse ionization cooling to also reduce longitudinal emittance, using bunched muon beams and incorporating RF cavities for reacceleration. The cooling lattice includes solenoids for tight focusing, dipoles for beam dispersion, and wedge absorbers for differential energy loss. This paper presents a complete implementation of cooling channels for BDSIM, a Geant4-based accelerator simulation tool, using appropriate analytic field models to account for fringe-field-dominated magnets. Components have been tested individually and validated against other tracking codes such as G4BeamLine. A tracking study leveraging this implementation is presented, simulating and optimizing a rectilinear cooling channel for the 6D cooling demonstrator. The analysis incorporates beam parameters from existing proton drivers, using outputs from targetry and capture system designs.
Paper: MOPS024
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS024
About: Received: 25 May 2025 — Revised: 02 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
MOPS025
Simulation studies and design updates for the nuSTORM facility
637
The neutrinos from Stored Muons (nuSTORM) experiment aims to create neutrino beams through muon decay in a storage ring, targeting %-level precision in flux determination. With access to two neutrino flavors, it enables precise measurement of $\nu$-A cross sections and exhibits sensitivity to Beyond Standard Model (BSM) physics. With muons in the 1-6 GeV/c momentum range, it covers neutrino energy regimes relevant to experiments like DUNE and T2HK. Additionally, nuSTORM serves as a step towards a muon collider, a proof of concept for storage rings, and a testbed for beam monitoring and magnet technologies. The lattice structure consists of a pion transport line and a racetrack storage ring based on a hybrid FFA design, with conventional FODO cells in the production straight combined with FFA cells in the return straight and arcs. This paper provides an update on the nuSTORM design and simulation efforts. It covers horn and lattice optimizations for producing and storing low-energy muons, describes tracking studies of the lattice to guide event normalization and presents the latest simulated neutrino fluxes.
Paper: MOPS025
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS025
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
MOPS030
Xcoll-BDSIM coupling for beam collimation
653
Xsuite is a comprehensive simulation toolkit for accelerator physics, with Xcoll serving as the dedicated module for collimation studies. These studies involve tracking particles through an accelerator and simulating their interactions with matter, taking into account non-linear elements and large betatron and off-momentum deviations. Particle-matter interactions can be modeled using an internal scattering model, Everest, or coupled to external codes. This paper presents the integration of Xcoll with the Geant4 libraries by utilizing the Beam Delivery Simulation (BDSIM) code. This coupling enables efficient tracking of diverse particle species through materials, along with realistic simulations of energy deposition and secondary particle production. The implementation is designed to be flexible, supporting the inclusion of detailed collimator geometries, beam-gas interactions, and crystal channeling effects.
Paper: MOPS030
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS030
About: Received: 28 May 2025 — Revised: 31 May 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
MOPS031
Preliminary results of crystal channelling optimisation in the LHC using reinforcement learning
657
The Large Hadron Collider (LHC) can operate with high intensity proton and heavy ion beams, both of which require a collimation system to ensure an efficient operation and to protect against damage to sensitive equipment along the ring. The crystal collimation scheme using bent silicon crystals as primary collimators was therefore introduced to improve the collimation efficiency for heavy ion-beams. The first operational deployment of crystal-assisted collimation was achieved in the 2023 Pb run. This demonstrated the required performance gain to safely handle high intensity ion beams, but undesired crystal rotation led to the loss of optimal performance during physics fills. The cause of this is thought to be mechanical deformation of the goniometer due to heating related to beam impedance effects. Hence, a conventional numerical optimiser was deployed to monitor and compensate for crystal angular errors based on a set of beam-loss monitors. The problem at hand, allows for the use of machine learning techniques to ensure continuous optimal channelling, minimising convergence time and eventually the optimization of crystals in multiple planes in parallel.
Paper: MOPS031
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS031
About: Received: 24 May 2025 — Revised: 03 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
MOPS036
Development of a pulsed magnet measurement bench using the stretched wire method
672
In the scope of the renewal of its injection systems, the ESRF-EBS has decided to implement a new scheme using Non-Linear Kickers (NLK) magnets. These pulsed octupole like magnets are extremely sensitive to any misalignment of the conductors carrying the currents resulting in a degraded magnetic field quality. It is then important to characterize precisely the transverse magnetic fields of these magnets to avoid any perturbation during the injection process. A new method to measure pulsed magnetic field is being developed at the ESRF-EBS readapting the classical method of the stretch wire bench for permanent magnet. This paper presents the advancement of this project and the first results.
Paper: MOPS036
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS036
About: Received: 27 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
MOPS038
Simulations of bunch length reduction techniques in the SLS booster
676
Modern injection schemes for light sources seek to explore the full 6D phase space in order to find creative ways of top-up injection with minimal perturbation to the stored beam. The longitudinal injection scheme is considered for the SLS 2.0 storage ring and, hence, the longitudinal profile of the injected beam becomes highly relevant for the injection efficiency. We simulate possible ways of reducing the bunch length in the SLS booster synchrotron. The feasibility of increasing the total RF voltage by installing additional or different RF cavities is considered. Furthermore, we simulate the impact of pulsed- or oscillating RF voltages and phases in order to compress the beam longitudinally at the expense of an increased energy spread.
Paper: MOPS038
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS038
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
MOPS039
Direct MOGA optimization of touschek lifetime and dynamic aperture using fast touschek tracking
680
A large momentum acceptance (MA) in 4th generation storage ring light sources is paramount to obtaining a long Touschek lifetime. However, the calculation of MA typically requires computationally expensive tracking simulations thereby complicating, or even disabling, the direct optimization of Touschek lifetime using numerical optimization algorithms. Our recent development of Fast Touschek Tracking allows obtaining the MA two orders of magnitude faster than standard MA tracking, thereby enabling direct optimization of Touschek lifetime. We present an example of a Multi-Objective Genetic Algorithm (MOGA) optimization of both on-energy dynamic aperture and direct Touschek lifetime using Fast Touschek Tracking for a 4th generation storage ring.
Paper: MOPS039
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS039
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
MOPS040
Start to end commissioning simulations for SOLEIL II storage ring
684
This paper presents comprehensive start-to-end commissioning simulations for the SOLEIL II storage ring upgrade, demonstrating the feasibility of achieving an ultra-low emittance of 84 pm-rad at 2.75 GeV. We detail a multi-step correction strategy addressing challenges posed by the dense magnet arrangement and limited number of BPMs and correctors. Our simulations encompass first turn trajectory correction, beam-based alignment (BBA), and Linear Optics from Closed Orbit (LOCO) techniques. Results demonstrate the robustness of the correction scheme in the presence of realistic errors, showing successful recovery of design emittance, suitable dynamic aperture, and expected beam lifetime. This work provides insights into an efficient commissioning strategy for SOLEIL II, supporting rapid commissioning and full performance restoration for user operations.
Paper: MOPS040
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS040
About: Received: 27 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
MOPS041
Status of the beam dynamics studies for the PERLE Energy Recovery Linac
688
PERLE (Powerful Energy Recovery Linac for Experiments) is a three-turn, high power Energy Recovery Linac under construction at IJCLab, France. It emerged from the design of the LHEC and FCC-eh and will serve as a hub for the validation of several technical choices and exploration of a broad range of accelerator phenomena in an unexplored operational power regime (up to 10 MW in its final version). Up to now, the final lattice design and phasing has been finalised. Current studies focus on non-linear effects and longitudinal dynamics. Also, the commissioning scheme is under developpement. We will present the status of the beam dynamics studies of the project, and highligth some of the ongoing studies
Paper: MOPS041
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS041
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
MOPS045
Considerations of a round beam operation at PETRA IV
696
Round beam operation is considered for the planned ultra-low emittance storage ring PETRA IV at DESY, Hamburg. With a natural emittance of 20 pm rad, we evaluate and discuss the advantages and challenges of sharing the emittance between transversal planes. The effect on single and coupled bunch instability thresholds, intra-beam scattering rates and Touschek lifetime of this operation mode are presented.
Paper: MOPS045
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS045
About: Received: 26 May 2025 — Revised: 01 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
MOPS046
Beam loading for counter-rotating high-intensity beams in the Muon collider
700
Muon colliders promise an efficient path to a multi-TeV energy collider facility. In the greenfield study, the final stage of the acceleration chain is planned as a series of four rapid-cycling synchrotrons (RCS). In each RCS, the RF systems are divided into several sections and shared by the two counter-rotating muon bunches. The accelerator requirements are driven by the need to preserve a maximum number of muons by taking advantage of time dilation. Therefore, maintaining a high accelerating voltage throughout the chain is essential, imposing superconducting RF cavities in the GV range. However, the high bunch intensity of up to $2.7\times 10^{12}$ particles per bunch and the 1.3 GHz TESLA cavity’s small aperture will result in induced voltages in the MV range. In the muon collider, the induced voltage of the counter-rotating beams will additionally impact the cavity voltage. This contribution presents the cavity voltage modulation and its impact on the beam loss and stability in the strong transient beam loading regime.
Paper: MOPS046
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS046
About: Received: 27 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
MOPS049
Beam loss scenarios for the SOLEIL II upgrade
712
SOLEIL II is an ambitious upgrade project that aims to reduce the horizontal emittance of the SOLEIL facility from 4 nm to 84 pm (to be further reduced to 50 pm by running with round beams). The SOLEIL II lattice will utilise a combination of permanent magnets and electro-magnetic corrector magnets. In the case of beam losses, it is of critical importance to localise the losses to certain shielded areas or dedicated collimators in order to prevent the risk of demagnetisation of the permanent magnets. The study and development of different beam loss scenarios will be presented.
Paper: MOPS049
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS049
About: Received: 27 May 2025 — Revised: 30 May 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
MOPS076
Coupling of codes for modeling high-energy-density conditions in fourth generation light sources
760
As previously described*, high-intensity beams of ultra-bright light sources present new machine protection concerns by creating high-energy-density (HED) conditions in beam-intercepting components. Simulating these HED conditions required us to develop a method for coupling three codes for particle dynamics (elegant), particle-matter interaction (MARS/FLUKA), and hydrodynamics (FLASH). This paper discusses the recent advancements made toward this effort including the use of phase and temperature dependent thermal properties such as thermal conductivity and specific heat, transition from MARS to FLUKA, and improved liquid phase dynamics. For benchmarking purposes we compare simulation results with experimental data collected during the final run of the Advanced Photon Source (APS) ring as well as observations of collimator surface damage following the first user run of the upgraded machine. This methodology is also used to make predictions of collimator damage in future APS-Upgrade (APS-U) runs and to examine locations where synchrotron radiation may lead to HED conditions.
Paper: MOPS076
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS076
About: Received: 30 May 2025 — Revised: 02 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
MOPS082
Simulation of the ion profile monitors in the Brookhaven AGS
768
Ion profile monitors (IPMs) provide a non-destructive means of measuring the transverse beam size of a passing ion beam in a particle accelerator. The Alternating Gradient Synchrotron (AGS) at Brookhaven National Lab is equipped with two types of IPMs: ion-collecting and electron-collecting. While ion-collecting IPMs are susceptible to significant distortions in the measured beam size due to the space charge of the passing beam, electron-collecting IPMs are much less affected. However, in the AGS, electron-collecting IPMs can only be operated periodically to preserve sensor lifespan, leaving ion IPMs as the sole source of consistent, real-time beam size feedback during operation. In this work, WarpX simulations of IPM operation are used to characterize the measured beam size as a function of beam parameters and IPM operating conditions. These simulations are then compared against experimental data collected from both ion and electron IPMs in the AGS. The findings aim to refine correction factors, enabling more accurate beam size estimations from ion IPM measurements, ultimately improving beam diagnostics and operational efficiency.
Paper: MOPS082
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS082
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
MOPS089
The Korea-4GSR storage ring lattice design
775
We present the lattice design features and performance evaluation of the Korea-4GSR storage ring. This greenfield ring has a 4 GeV beam energy, an 800 m circumference, and 28 cells. A natural emittance of 62 pm is achieved through the implementation of four longitudinal-gradient bends and six reverse bends within the hybrid multi-bend achromat unit cell. The ring includes two high-beta straights, designed to be nearly transparent to the normal straights. Sextupole and octupole magnet strengths have been optimized to suppress major detuning parameters, enabling the ring to achieve a large dynamic aperture and momentum aperture. Commissioning simulations were performed to investigate the optics correction strategy for each commissioning stage and to estimate the performance of the ring under error conditions.
Paper: MOPS089
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS089
About: Received: 23 May 2025 — Revised: 01 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
MOPS138
Simulation of machine-induced background to ALICE in the 2023 LHC ion run
808
During the 2023 ion run at the LHC, where crystal collimation was regularly adopted for the first time, strong background levels were observed at the Inner Tracking System (ITS) of the ALICE detector. Some of the readout chips became saturated, causing losses of angular acceptance. This background was mitigated using a dispersion knob in the beam optics, letting some residual background remain. Considering that the next upgrade of the ALICE ITS foresees a further reduction of the interaction chamber aperture, understanding the mechanisms leading to this background appears critical to envision appropriated mitigation solutions. Preliminary studies showed that this background was related to losses at the upstream tertiary collimator (TCT), impacted by 207Pb82+ ions issued from beam interaction with the crystals of the primary collimation stage. Based on FLUKA simulations, this paper investigates the propagation of the tertiary collimator showers towards the ALICE cavern.
Paper: MOPS138
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS138
About: Received: 27 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
MOPS141
Enhancing beam intensity in SIS18 by a two-plane multi-turn injection approach
819
The existing synchrotron SIS18 will serve as an injector for the FAIR (Facility for Antiproton and Ion Research) complex in booster mode operation. FAIR requires high-intensity beams, placing stringent demands on increasing beam currents in SIS18. Operational experience has shown that significantly increasing beam intensity in SIS18 necessitates both a higher current from UNILAC and improved injection efficiency into SIS18. Currently, injection into the SIS18 synchrotron is performed using conventional multi-turn injection (MTI) in the horizontal plane. To significantly enhance beam intensity in SIS18, we propose implementing a two-plane multi-turn injection scheme. This method aims to boost beam intensity to the desired levels (e.g., uranium beams exceeding 1x1E11 per cycle), even within the current capabilities of UNILAC. This paper discusses how MTI gain can be increased with high efficiency through a two-dimensional technique of painting Lissajous-like patterns in horizontal-vertical space using an inclined electrostatic septum. Simulation examples are presented, illustrating the characteristics of the beam created in SIS18 and the potential effects of space charge forces.
Paper: MOPS141
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS141
About: Received: 25 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
TUAN1
A Study on Eddy Current Distribution in the Coating Layer of a Nonlinear Kicker Chamber
849
This study presents 2D approximated expressions for eddy currents in the Ti-coated layer of a nonlinear kicker and compares them with numerical simulations. Nonlinear kicker-based injection schemes have be-come popular in recent years and are used at several facilities. Eddy currents, which depend on both the applied magnetic field and the chamber’s geometry, can create unwanted field components. The proposed approximations offer a fast and practical way to esti-mate the effects of these eddy currents.
Paper: TUAN1
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUAN1
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
TUPB002
Consideration for improving the longitudinal beam matching between RCS and MR at the J-PARC
912
The J-PARC 3 GeV Rapid-Cycling Synchrotron (RCS) delivers the high-intensity proton beam to the 30 GeV Main Ring (MR). The improvement of longitudinal beam matching between RCS and MR is desired to suppress the beam loss in the MR. A scenario to improve the longitudinal beam matching between RCS and MR is designed. For the RCS, the bunch lengthening scheme using the unstable fixed point generated by the second harmonic is considered. For the MR, the RF voltage pattern is adjusted to match the longitudinal beam emittance of the RCS. The details of the scenario for improving the longitudinal beam matching between RCS and MR and the results of beam simulation studies are reported.
Paper: TUPB002
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB002
About: Received: 26 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
TUPB004
Measurement of the transversal Muon Rate at the proposed CODEXb experiment with the Timepix3 Radiation Monitor
920
Using a Timepix3 radiation monitor, we measured the muon rate at the proposed CODEXb experiment location within the Large Hadron Collider (LHC) during luminosity production at the LHCb collision point. Filters were applied to the data to differentiate the background radiation from the muon signal by analyzing the particle track morphology—specifically cluster type, length, and angle within the detector. The resulting filtered muon rate was determined to be 8.6$\pm$1.5 counts/(cm $ \cdot$ pb$^{-1}$). These results were further compared to simulations performed with the FLUKA Monte Carlo code, showing agreement within the uncertainties.
Paper: TUPB004
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB004
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
TUPB007
Radiation levels from a Beam Gas Curtain instrument at the LHC at CERN during ion operation
932
A prototype Beam Gas Curtain (BGC) monitor was installed on beam 1 at the Large Hadron Collider (LHC) at CERN to provide 2D images of the transverse beam profile during the ongoing Run 3 (2022 - to date) and in view of the High Luminosity LHC upgrade (HL-LHC). By design, the BGC operation generates collisions between the beam particles and an injected gas jet proportionally to the beam intensity and the gas density, possibly causing radiation-induced issues to the downstream LHC equipment. This operation has been studied for the proton run, and now the scenario for lead (Pb) ion beam is scrutinized. The radiation showers from the BGC are characterized using measured data from different LHC radiation monitors during the Run 3 BGC operation, along with Monte Carlo simulations with the FLUKA code. Finally, predictions of the expected radiation showers during operation of the BGC in the HL-LHC era are discussed.
Paper: TUPB007
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB007
About: Received: 28 May 2025 — Revised: 29 May 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
TUPB011
Resonance island formation due to adiabatic tune change in RHIC
944
A stored proton beam may become unstable when the horizontal tune slowly approaches a quarter integer resonance.This paper discusses this phenomenon in the context of an Accelerator Physics Experiment that was conducted in the Relativistic Heavy Ion Collider, in which the horizontal tune was ramped through a fractional tune of 0.75 in the presence of strong octupolar fields.
Paper: TUPB011
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB011
About: Received: 28 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
TUPB012
Bunch filamentation within resonance islands
948
This paper presents turn-by-turn observations of internal and external filamentation within the Poincare contours of a fourth order resonance during an Accelerator Physics Experiment (APEX) in the Relativistic Heavy Ion Collider (RHIC). Beam position monitors measured the turn-by-turn evolution of the center-of-charge of the captured beam. The fraction of beam outside the island soon comes to contribute marginally to the center-of-charge signal. Simulation results are compared with experimental data.
Paper: TUPB012
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB012
About: Received: 28 May 2025 — Revised: 01 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
TUPB013
Towards axion searches with polarized hadron beams at GSI/FAIR
952
Axions, originally introduced to solve the strong CP problem, are leading dark matter candidates appearing in various Standard Model extensions. At low masses, axion-like particle (ALP) dark matter behaves as a classical field, potentially detectable when its frequency resonates with a beam's spin-precession frequency. The JEDI collaboration's proof-of-principle experiment at COSY set upper limits on oscillating EDMs caused by ALPs, though no signals were observed. This presentation discusses COSY results and recent efforts to explore the feasibility of conducting axion search experiments using existing accelerators at GSI/FAIR with polarized hadron beams.
Paper: TUPB013
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB013
About: Received: 27 May 2025 — Revised: 30 May 2025 — Accepted: 31 May 2025 — Issue date: 06 Jun 2025
TUPB015
Evaluating the feasibility of TPS high heat load components for high-current operation using TMSI
959
The Taiwan Photon Source (TPS) currently operates at 500 mA beam current, with future evaluations targeting 800 mA to assess the feasibility of high-intensity operation. This imposes significant thermal and mechanical challenges on high heat load (HHL) components, such as premasks, fixed masks, slits, and absorbers, in the storage ring and front end. To systematically evaluate the severity of existing designs, we developed the Thermal-Mechanical Severity Index (TMSI), which quantifies combined thermal and mechanical stresses, enabling targeted comparisons within component categories. Finite Element Analysis (FEA) simulations using ANSYS were conducted to provide detailed thermal and thermo-mechanical results, supporting the validation of the TMSI framework. TMSI streamlines component assessment, reduces the need for exhaustive case studies, and facilitates prioritization of redesigns to ensure the reliability and longevity of HHL components. This methodology represents a practical and efficient approach to advancing TPS design and operation for next-generation synchrotron performance.
Paper: TUPB015
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB015
About: Received: 07 May 2025 — Revised: 02 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
TUPB018
Towards tailored beam distributions for fixed target experiments at CERN
967
The time-of-flight (nTOF) facility at CERN uses neutrons produced by a proton beam interacting with a fixed target. To prevent target damage, an upper bound on the peak energy density has been imposed. Adhering to this constraint requires a large beam size. Similarly, at CERN’s North Area, a large beam size is required at the septa splitting the beam towards different experiments. However, both cases suffer from limitations associated to losses of the primary beam, leading to poor transmission efficiency and high radioactive activation. This paper proposes an alternative approach by manipulating the beam distribution. Given the absence of strong nonlinear elements in both transfer lines, the focus shifts to tailoring the distribution before extraction. Particle tracking simulations are presented alongside experimental results, characterizing the phase space distribution as a function of machine parameters. Advanced deep learning methods that enable efficient exploration of the parameter space are also discussed.
Paper: TUPB018
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB018
About: Received: 27 May 2025 — Revised: 30 May 2025 — Accepted: 30 May 2025 — Issue date: 06 Jun 2025
TUPB019
Investigation and mitigation of magnetic field emissions in the SMH16 septum system's high-current cable connections
971
The SMH16 system at CERN is a pulsed septum magnet driven by a single period of a flattened sine wave current with a fundamental frequency of approximately 2.5 kHz and a peak current of 28 kA. The magnet connects to its pulse generator via ten high-voltage, high-power cables, each containing go, return, and ground conductors and coarse shielding. Due to the high currents, magnetic field emissions could interfere with nearby equipment and affect electromagnetic compatibility. This work investigates these magnetic field emissions and evaluates potential shielding measures. 2D field simulations of the cable connections to model the emissions and assess the effectiveness of additional shielding configurations have been conducted. To validate the simulations, time-dependent magnetic field measurements using a magnetic near-field probe, and a custom Hall probe were performed on a section of the cable connection in a full-scale test setup of the SMH16 system, both with and without extra shielding around the cable bundle. The results showed good agreement between simulations and measurements. Additional shielding can significantly reduce magnetic field emissions.
Paper: TUPB019
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB019
About: Received: 28 May 2025 — Revised: 30 May 2025 — Accepted: 01 Jun 2025 — Issue date: 06 Jun 2025
TUPB020
Injection simulations of space charge dominated proton beams in IOTA
975
A 2.5 MeV proton injector is being constructed for the IOTA ring at Fermilab to study the interaction of nonlinear integrable optics (NIO) with high space charge beams. Space charge in the transport line from the RFQ to the injection location has a significant current dependent effect on the phase space. Simulation studies to support efficient injection of intense bunches into IOTA are presented, included schemes to inject directly into NIO lattices.
Paper: TUPB020
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB020
About: Received: 28 May 2025 — Revised: 30 May 2025 — Accepted: 30 May 2025 — Issue date: 06 Jun 2025
TUPB021
Effects of beam plane correlation on injection efficiency
979
The effectiveness and efficiency of a beam injection scheme is crucial to achieve high beam intensities while minimizing possible beam losses. The classical method for injecting from a linac to a synchrotron is the multi-turn injection. In this scheme the quality of the injected beam as well as of the injection scheme depends on factors as beam emittance, type of local bump ramp, chromaticity, dispersion and beam intensity. This approach relies on the decorrelation between the planes of the injected beams. However, investigations on the beam coming from the linac have suggested the possibility that a beam correlation may exist*. We present here an investigation of the effect of a correlated beam on the efficiency of the multi-turn injection for several degrees of correlation.
Paper: TUPB021
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB021
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
TUPB023
Simulation studies on bent silicon crystals for loss reduction in slow extraction operation at J-PARC Main Ring
986
Reducing beam loss during slow extraction remains a critical challenge for the J-PARC Main Ring, which aims to enhance beam power for its 30 GeV proton beam. Since beam loss during slow extraction mainly occurs at the electrostatic septum, it is important to reduce beam loss at this location. Researchers at CERN SPS have recently reported that beam loss can be reduced by installing bent silicon crystals in the accelerator ring and utilizing their charged particle deflection effect. In this paper, we report the results of a simulation study on the expected beam loss reduction effect when the bent silicon crystal is installed upstream of the electrostatic septum of the J-PARC Main Ring and the beam deflection effects of the bent silicon crystal, called channeling or volume reflection, are utilized. The required size and installation position of the silicon crystal, and the required accuracy for adjusting the position and angle will also be reported.
Paper: TUPB023
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB023
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
TUPB024
Simulations of magnetic field effects on 3-GeV proton beam brought by magnets for muon beam in future proton beam transport line of J-PARC
990
A high-power 3-GeV proton beam from a rapid cycling synchrotron (RCS) is transported to targets for muon and neutron production at Materials and Life Science Experimental Facility (MLF) by a 3-GeV RCS to Neutron facility Beam Transport (3NBT) line in J-PARC. Recently, the design power of 1 MW has been achieved, which has initiated a future plan of MLF second target station (TS2). For the future plan, design studies have been started for a new beam transport line to the TS2 target, which works as a source for both muon and neutron. In this study, 3-GeV proton beam transport is simulated in the vicinity of the TS2 target, where a bending magnet for muon separation and a capture solenoid are aligned. In this presentation, we report magnetic field effects on the proton beam brought by those magnets and correction of the effects.
Paper: TUPB024
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB024
About: Received: 07 Apr 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
TUPB029
Simulations of beam halo distributions for a feasibility study of in-vacuum gravitational experiments at the LHC
1009
Within the realm of general relativity, the measurement of signals coming from relativistic celestial bodies have offered great insights. However, the relatively low frequency of these signals and the lack of control over their source may make the creation of well-controlled laboratory environments desirable. One possibility is to measure the relativistic beams in the Large Hadron Collider (LHC) at CERN using a milligram-scale monolithic pendulum. This would offer the possibility to test general relativity and alternative theories of gravity in an entirely new parameter regime, where the source of gravity is the almost pure kinetic energy of the ultra-relativistic particles. The low-bandwidth of the source, combined with the controllability of the setup, may offer new opportunities and insights in gravity-related research. To design the experiment, it is necessary to analyze the factors that contribute to the deterioration of the signal-to-noise ratio. One of the contributors is the impact on the pendulum of beam halo particles. This paper presents an initial assessment of the impact of beam halo on the detection of gravitational signal.
Paper: TUPB029
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB029
About: Received: 26 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
TUPB032
Application of bayesian optimization in magnetic horn design
1020
Bayesian optimization is an effective method for designing complex systems with costly, non-analytic black box objective functions. It enables efficient exploration of the parameter space, making it well-suited for challenging problems in accelerator design which involve computationally intensive simulations such as FLUKA. This study presents a framework to apply Bayesian optimization techniques to design the magnetic horn of Neutrinos from Stored Muons (nuSTORM) experiment for increased pion capture. The optimization process spans a wide range of operational energies, from 1 to 7 GeV, to address the physics reach of nuSTORM. Batch sampling is enabled through specialized acquisition functions, allowing simulations to run in parallel across a computational cluster and significantly reducing the time needed to identify optimal target and horn configurations for the muon source. By leveraging the surrogate models generated through Bayesian optimization, horn configurations at different energies are systematically compared. This facilitates sensitivity studies to determine a minimal set of horn designs that efficiently cover the nuSTORM kinematic range.
Paper: TUPB032
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB032
About: Received: 28 May 2025 — Revised: 01 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
TUPB042
Optimising focusing parameters of very high energy electron beams for radiotherapy using Monte Carlo simulation
1040
Very high energy electron (VHEE) beams, with energies of 100 MeV and above, offer favourable properties for radiotherapy, such as deep penetration depth and reduced sensitivity to tissue heterogeneity. Numerous simulation and experimental studies have investigated these properties for clinical application. In this study, we use Monte Carlo simulation using TOPAS to obtain the depth-dose profiles of VHEE beams with varying energy and focusing parameters. An empirical model is fitted to the central axis dose, yielding parameters that characterise the depth-dose profile. A linear interpolator then maps these fitting parameters to the focusing parameters, allowing us to identify the optimal focusing parameters. The results presented here are independent of the beamline and can therefore guide the design of a final focusing systems for VHEE beams.
Paper: TUPB042
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB042
About: Received: 27 May 2025 — Revised: 30 May 2025 — Accepted: 31 May 2025 — Issue date: 06 Jun 2025
TUPB050
Design study of HTS air-cored cyclotron coil system for medical RI production
1059
The high current density of HTS material allows electromagnet to induce sufficiently strong magnetic field without relying on any iron core. This permits the design of air-cored cyclotron, where the absence of iron core brings the properties of light-weight and high field reproducibility, making it an ideal medical cyclotron to be installed inside hospitals. However, the cyclotron coil system need to induce highly accurate field while satisfying the engineering restriction from the HTS coil. Compact size, small fringe field and minimum fabrication cost are also desirable at the same time. A HTS coil system of air-cored cyclotron is designed with the above restrictions taken into consideration. Multiple beam type accelerations that are required for medical RI production are simulated, in order to verify the usefulness of this design. In this work, the coil system design, the magnetic field and the HTS coil properties are presented. The feasibility of actual fabrication and in-hospital installation is discussed.
Paper: TUPB050
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB050
About: Received: 27 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
TUPB055
Exploring the potential of accelerator-based neutron generators in modern research
1065
The Institute for Plasma Research in India set up an accelerator-based 14 MeV neutron generator utilizing Electron Cyclotron Resonance Ion Source technology. This advanced generator can produce 1012 neutrons per second in continuous and pulse modes. By directing deuterons at a TiT target, it generates fast neutrons that are essential for various applications such as fusion experiments, electronics testing, feasibility studies of medical isotope production, neutron radiography, etc. Various independent neutron diagnostics such as diamond detectors, proportional counters, and foil activation have been installed in the Neutron Generator. These techniques provide precise measurements of neutron flux, which are cross-checked with the associated alpha diagnostic technique to ensure accuracy. Additionally, lab-scale experiments at IPR have explored neutron irradiation for medical radioisotope production and radiation-induced damage in electronic components. This paper highlights the significance of precise measurement techniques and demonstrates the critical role of neutron generators in advancing research and practical applications, from medical isotopes to fusion neutronics studies.
Paper: TUPB055
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB055
About: Received: 26 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
TUPB056
Development of a friendly high-energy irradiation environment for future space developments
1068
Effect assessments of high-energy radiations on materials and equipment are expected to become increasingly important in near future space developments. We initiated a project to construct an irradiation environment with high-energy radiations using the electron linear accelerator at Nihon University. The advantages of using this accelerator include the accelerations up to 100 MeV for high-energy and high-dose irradiations, its easy accessible location from Tokyo area. These advantages help many users including venture companies to use the irradiations with much less difficulties, that we consider as an important key to enhance future space developments. The electron linear accelerator sends electron beams with a wide energy range to the FEL line by bending them 90 degrees with two 45-degree bending magnets. Irradiation tests are planned to be conducted using the radiation produced in this process. In this study, we present a simulation result on the acceleration process of the electron beam and the amount of radiation generated by the 45-degree bending magnets. We also show dosimeter measurements by the high-energy irradiations to be compared with the simulation results.
Paper: TUPB056
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB056
About: Received: 29 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
TUPB057
Ultra-high spatial resolution in micron scale achieved by a practical cascade high energy electron radiography in HERPL
1072
As a new scheme, High Energy Electron Radiography (HEER) was considered as one of the novel mesoscale diagnostic methods for high energy density matter (HEDM) because of powerful penetration, high space-time resolution and large density dynamic diagnosis range. In this work, we R&D a practicle cascade HEER composed of a electromagnetic beamline and a permanent magnet HEER in High Energy Electron Radiography Research Platform in Lanzhou (HERPL). The field of view of the cascade HEER is about Φ3mm, and its total length is half that of the electromagnetic HEER with the same magnification. 50 MeV electron beams with picosecond pulse width bunch were used to image a TEM grid to study the spatial resolution. The excellent result was obtained with spatial resolution about 0.6 μm. In addition, electron bunch train and ultra-fast imaging acquisition system prepared for dynamic HEER were studied in this paper.
Paper: TUPB057
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB057
About: Received: 27 May 2025 — Revised: 01 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
TUPB066
Design and calculation of the RF system of the U400R cyclotron
1090
Flerov Laboratory of Nuclear Reaction of Joint Institute for Nuclear Research carries out the works under creating of FLNR JINR Irradiation Facility based on the cyclotron U400R. The main systems of U400R are based on the U400 cyclotron. The objectives of this project are: - to increase the intensity of accelerated 48Ca ion beams from 1.2 puA to 2 puA; - to expand the energy range of accelerated ions from 2–20 MeV per unit mass to 0.8–25 MeV per unit mass; - to extract ion using stripping foil and deflector; - to reduce the energy spread in the beam to 3×10⁻³. The results of calculating the parameters of the new RF-system are given in this work.
Paper: TUPB066
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB066
About: Received: 27 May 2025 — Revised: 02 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
TUPB068
Density measurements and simulations on confined electron column in GL2000 Gabor-lens device
1097
GL2000 Gabor-lens (GL) is a 2m long device built mainly for focusing and space charge compensation of hadron beams in energy ranges up to GeV. The electron cloud is initially produced by cold-cathode method with gradually ionisation of residual gas and is confined in a cylindrical trap much longer compared to previous constructed lenses. Density measurements were carried out at the test-stand in Goethe University in 2024. Outgoing stream of residual gas ions was detected within cylindrical spectrometer mounted on axis outside of the lens. Due to the dependency of the kinetic energy on starting potential, the on-axis potential and therefore confined average charge density can be derived. Measured densities were evaluated in a range of $10^{14}$-$10^{15} m^{-3}$. A large scale multi-particles Monte-Carlo-PIC (particle-in-cell) simulations with electrons and ions were carried out to understand collective phenomena in non-neutral plasma and to use the latter for linear and non-linear beam manipulation. Measurements and simulation results will be presented.
Paper: TUPB068
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB068
About: Received: 28 May 2025 — Revised: 31 May 2025 — Accepted: 31 May 2025 — Issue date: 06 Jun 2025
TUPB075
Bunch lengthening of the extraction beam using second harmonic in J-PARC RCS
1109
The 3GeV Rapid-Cycling Synchrotron (RCS) at J-PARC supplies the beam to the Main Ring (MR). Under the current operating conditions, there is the longitudinal beam mismatch between RCS and MR. To improve the RCS-MR longitudinal matching, a method for the bunch lengthening of RCS at the extraction is proposed. The method is based on introducing a second harmonic RF voltage at beam extraction and placing the beam at the unstable fixed point. The considerations of the bunch lengthening in the RCS are described in this presentation. The focus is on optimizing the second harmonic RF voltage pattern. Demonstrations of introducing a second harmonic RF voltage are also discussed.
Paper: TUPB075
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB075
About: Received: 07 Apr 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
TUPB090
Impedance analysis for the ALS-U kickers
1116
We present recent impedance modeling studies of the kicker systems developed for the Advanced Light Source Upgrade (ALS-U), including ferrite-loaded kickers, stripline-type fast kickers, and septa. The modeling supports the injection/extraction systems to ensure beam stability in the accumulator and storage rings. In addition, it provides guidance for component fabrication and offline testing by incorporating realistic factors such as mechanical tolerances and assembly specifications.
Paper: TUPB090
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB090
About: Received: 28 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
TUPB099
Recent developments in delivering mixed helium and carbon ion beams at MedAustron
1124
Simultaneous irradiation with mixed helium and carbon ions is being proposed for online range verification in carbon radiotherapy. In 2024, a mixed $^4$He$^{2+}$ and $^{12}$C$^{6+}$ beam, generated by sequential injection of helium and carbon ions into the synchrotron, was extracted successfully for the first time at the MedAustron ion beam therapy and research center. This double injection scheme comes with challenges concerning the capture, acceleration, and slow extraction, as injection energy offsets and differences in horizontal phase distributions have to be considered in addition to the small offset in charge-to-mass ratio between $^4$He$^{2+}$ and $^{12}$C$^{6+}$. This proceeding reports on recent developments in the delivery of this mixed ion beam at MedAustron using a double injection scheme, which includes an additional deceleration ramp for helium ions between the injections of helium and carbon, as well as progress towards a measurement setup for the time-resolved quantification of the ion mixing ratio at delivery.
Paper: TUPB099
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB099
About: Received: 27 May 2025 — Revised: 31 May 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
TUPM004
Simulations and experimental commissioning results of the AWAKE Run 2 photoinjector
1148
AWAKE (Advanced Wakefield Experiment) is the world’s first proton-driven plasma wake field acceleration experiment and has demonstrated the acceleration of electrons to several GeV’s in its first Run. The goal of Run2 is acceleration of a witness bunch whilst preserving beam quality and experiment scalability. AWAKE drives high gradient plasma wake fields using a proton beam, then a secondary electron beam is accelerated which is externally injected from a dedicated injector which consists of an S-band Rf-gun and an X-band bunching and acceleration system. This S band RF-Photoinjector for the AWAKE Run 2 experiment at CERN is currently being commissioned. The obtained experimental results are presented and compared to simulations in this paper. Overall, the commissioning demonstrates successful matching of beam parameters with the design values, supported by ASTRA simulations. This lays the groundwork for low emittance electron beam injection into the AWAKE plasma and opens possibilities for future high-gradient acceleration experiments.
Paper: TUPM004
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM004
About: Received: 19 May 2025 — Revised: 30 May 2025 — Accepted: 30 May 2025 — Issue date: 06 Jun 2025
TUPM005
Recommissioning of the University of Hawai‘i LINAC and Free Electron Laser
1152
The electron beam linear accelerator (linac) at the free-electron-laser (FEL) laboratory of the University of Hawai‘i at Mānoa, originally developed by Prof. John Madey, has undergone recommissioning. The S-band linac delivers 45 MeV electron beams with 170 mA pulse current and 4–8 $\mu$s pulse duration to drive an infrared FEL oscillator. Recent efforts include restoration of the microwave thermionic gun with a new LaB$_6$ cathode, upgraded vacuum and RF systems, and development of a Python-based beam dynamics model to recover operational magnet settings and optimize beam transport. These upgrades address key technical challenges to restart the accelerator and pave the way for future FEL experiments, including coherent pulse shaping and inverse Compton scattering x-ray generation.
Paper: TUPM005
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM005
About: Received: 27 May 2025 — Revised: 02 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
TUPM008
Six-dimensional phase space reconstruction with multimodal CNN
1159
The information on phase space in all six dimensions is required for various accelerator experiments. We developed an algorithm based on Convolutional Neural Network (CNN) that can be used instead of the traditional back projection techniques because it is less computationally intensive and has a simple architecture. Our method has shown consistency with the simulation, and we plan to validate it on data taken at the KEK–Superconducting Test Facility (STF).
Paper: TUPM008
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM008
About: Received: 29 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
TUPM015
Design study for a transverse deflecting cavity based de-chirper
1173
A collaboration is underway to experimentally demonstrate a novel approach using deflecting cavities to control a particle beam’s longitudinal chirp. While a series of deflecting cavities produces negative chirp, the de-chirping process requires additional modification on the beamline. It has been known that inserting negative drift sections between TDCs enables de-chirping. While the original idea of negative drift requires a series of five quadrupole magnets, the experimental conditions cannot provide enough quadrupoles and space for them. Additionally, it is confirmed that a negative drift using three quadrupoles introduces a significant increase in beam size and emittance in one of the transverse planes. Thus, we propose a new method to enable de-chirping by inserting a series of three quadrupoles. Here, we form a negative identity transport instead of the negative drift. Simulations have been performed to explore this new opportunity. We present the result of this design study.
Paper: TUPM015
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM015
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
TUPM031
Courant-Snyder formalism for modeling, optimizing and simulating broadband THz radiation transport
1208
In order to exploit the scientific potential of user-oriented accelerator facilities, it is necessary to provide adequate pump sources to enable pump-probe science. The EuXFEL R&D project, STERN, aims to equip X-ray users with an accelerator-based THz source matching the high repetition rate of the XFEL. The proposed THz radiation generation methods involve Cherenkov wakefield structures and diffraction radiation, aiming to produce a spectrum from 300 GHz to 30 THz. To enable experimental characterization, both broadband and narrowband pulses must be transported through a single beamline to a radiation-shielded laboratory. A major challenge has been the simulation, optimization and design of the STERN beamline. The OCELOT accelerator lattice optimizer is adapted for optical transport with mirrors substituting traditional focusing magnets. The performance is corroborated using a THz transport code that considers beam clipping and diffraction. The optimized beamline achieves efficient transport over 10 meters, maintaining over 75% source-to-end efficiency across the frequency range. This development marks a significant step forward in THz beamline design for advanced applications.
Paper: TUPM031
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM031
About: Received: 28 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
TUPM045
Latest dark current studies of RF photocathode gun of Delhi Light Source
1229
The Delhi Light source is a pre-bunched Free Electron Laser facility to generate coherent THz radiation. The electron beam is generated from a normal conducting 2.6 cell RF photocathode (PC) gun operated at 2860 MHz. The RF gun is powered by a high power RF source for a duration of 4 µs at 10 Hz repetition rate. The dark current during the operation of the RF gun has been found to be substantially high with increasing forward powers (above 3 MW) even after prolonged RF conditioning. Dark current measurements has been done with an in-house developed faraday cup with an objective to understand the possible primary dark current source from locations at the PC that witnesses high accelerating fields. The measurements include the study of solenoid field variation to understand the dark current energies and effect of its steering to understand the possible dark current locations. Simulations to make inference from the measurements has been done assuming different radial position of dark current emitters at the PC surface. The details of the measurements, simulation results and the inference drawn are discussed in the paper.
Paper: TUPM045
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM045
About: Received: 27 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
TUPM049
Studying photoemissive properties of stable Cs-Sb compound thin-film photocathodes using a combination of Monte Carlo simulations and Density Functional Theory
1240
Cs-Sb compound thin-film photocathodes are an excellent candidate to produce bright electron beams for use in various accelerator applications. Despite the virtues of these photocathodes being known, the mechanics that govern their photoemission are not well-understood. Crystalline and other material properties affect the mean transverse energy (MTE) and quantum efficiency (QE) and, thus, the overall brightness. Electrons photoemitted from these thin-film crystals experience an unexpected energy loss similar to that found in bulk crystals despite their being a significantly shorter transport phase. Deeply understanding the relationship between the crystalline properties and the emitted electron beam’s brightness, as well as this drop in energy, is vital to generating ultra-bright electron beams for advanced accelerator applications. The purpose of this work is to use the Monte Carlo method to simulate photoemission from semiconducting films with electronic band structure parameters supplied by Density Functional Theory (DFT) calculations. This method is used to study all steps of photoemission and to identify the key parameters necessary for optimizing photocathode performance.
Paper: TUPM049
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM049
About: Received: 29 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
TUPM054
Progress towards kick and cancel injection for Diamond-II
1247
With the aim of maintaining transparent and efficient injection during top-up, a kick-and-cancel injection scheme has been developed for Diamond-II. In this, stripline kickers are used with 3 ns pulses to deflect individual bunches, with the stored bunch receiving two kicks separated by 180 degrees phase advance to leave it on-axis and the injected bunch timed to arrive at the second kick. In this paper we present progress with the hardware design and recent prototyping results, alongside updates to the simulations.
Paper: TUPM054
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM054
About: Received: 19 May 2025 — Revised: 02 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
TUPM058
Simulation and optimization of nonlinear kicker injection for PAL-EUV storage ring
1259
The PAL-EUV storage ring has been designed to provide extreme ultra violet (EUV) beams, and is currently under commissioning. With a circumference of 36 m and an electron beam energy of 400 MeV, injection from the booster to the ring is achieved using a nonlinear kicker. Successful injection requires precise tuning of the kicker’s timing delay and maximum strength to match the injected beam’s conditions. This paper investigates the optimization method for these parameters and presents the results obtained through simulation.
Paper: TUPM058
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM058
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
TUPM059
SPS-II beam injection using a non-linear kicker
1262
SPS-II is the fourth generation electron storage ring in Thailand. The medium-sized ring constructed with a Double- Triple Bend Achromat (DTBA) cell provides low emittance and high capacity for the beamlines. To complement the compact storage ring with DTBA cell, a Non-Linear Kicker (NLK) was chosen for beam injection. This approach not only simplifies the injection system by reducing the number of required kickers but also enhances the overall reliability and efficiency of the injection process. This paper discusses the injection dynamics and optimization strategies associated with implementing the NLK in the SPS-II storage ring. Through comprehensive simulations and analyses, we demonstrate the NLK’s efficacy in achieving high injection efficiency.
Paper: TUPM059
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM059
About: Received: 26 May 2025 — Revised: 29 May 2025 — Accepted: 29 May 2025 — Issue date: 06 Jun 2025
TUPM061
Spectrum-based alignment of SIRIUS undulators
1269
Recently, two SIRIUS beamlines, EMA and PAINEIRA, received their definitive insertion devices (IDs). Both IDs are in-vacuum devices (IVUs), the first of this kind at SIRIUS. Due to the proximity of the IVU cassettes to the electron beam, the spectrum emitted by these devices is highly sensitive to misalignments of the ID magnetic center. Such misalignments can result in photon flux losses, spectral shifts toward lower energies, and broadening of the resonance. This work presents the application of O. Chubar’s* spectrum-based alignment method to one of the new SIRIUS IVUs, aiming to optimize its performance at the beamline.
Paper: TUPM061
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM061
About: Received: 22 Apr 2025 — Revised: 30 May 2025 — Accepted: 31 May 2025 — Issue date: 06 Jun 2025
TUPM071
Finalizing the multiphysics design of a high heat-load superconducting undulator
1299
RadiaBeam is developing and manufacturing a 15mm period, high temperature superconductor undulator using Magnesium Diboride (MgB2) wire at 10K-15K temperature range. This temperature range can be achieved by cryocooler, a simpler and less expensive cryogenic solution compared to a liquid helium approach. After optimizing the thermal-mechanical design, the operating temperature is finalized at 7K. We examine the current density, critical field, tensile stress, tensile strain, and temperature of MgB2 wire in multiphysics approach and determine the operating field to be 1.13T with safety margin. A quench-protected power system is developed for training the SCU to the operating point in controlled ramp rate. The SCU will be characterized by in-vacuum pulse wire measurement system.
Paper: TUPM071
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM071
About: Received: 28 May 2025 — Revised: 31 May 2025 — Accepted: 31 May 2025 — Issue date: 06 Jun 2025
TUPM076
Refined FLUKA simulation model of neutrino-induced effective dose from a multi-TeV muon collider
1303
Most muons injected into a muon collider decay into an electron (or positron) and a neutrino-antineutrino pair, producing a narrow disk of high-energy neutrinos emitted tangentially to the beam in the collider plane. These neutrinos reach the Earth’s surface at distances far away from the collider. Vertical diffusion of the neutrino cone, reducing integrated neutrino flux at any surface exit point, has been proposed as mitigation technique. This study presents effective dose calculations performed with the FLUKA Monte Carlo code for various geometrical models, each representing conservative radiation exposure scenarios from neutrino flux emerging from the ground at specific distances from muon decay points. These scenarios correspond to different parts of the muon collider ring: bending sections and long straight sections housing experiments. Results are provided as effective doses for annual exposure scenarios with a 100% occupancy. Two muon beam energies are considered: 1.5 TeV and 5 TeV, with a more detailed approach applied to the higher energy.
Paper: TUPM076
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM076
About: Received: 27 May 2025 — Revised: 01 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
TUPM086
Simulation study of beam-driven plasma wakefield experiments on CLARA
1327
The Compact Linear Accelerator for Research and Applications (CLARA) is an electron test facility capable of delivering tunable 250 MeV electron beams with up to 250 pC charge to the Full Energy Beam Exploitation (FEBE) experimental area . In this study, we investigate the feasibility of conducting beam-driven plasma wakefield acceleration (PWFA) experiments using the CLARA beam and experimental area. We present simulations of various potential experiments, considering the baseline and R&D beam parameters expected to be delivered to the FEBE experimental chambers*. Our findings highlight the potential for CLARA to support advanced PWFA research, with detailed analysis of beam dynamics and experimental configurations.
Paper: TUPM086
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM086
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
TUPM087
A high-efficiency dielectric wakefield energy booster for CLARA
1331
Structure-based wakefield acceleration, using dielectric-lined or corrugated waveguides, is a novel acceleration method currently being explored by several research groups globally. This technology facilitates the transfer of energy from a high-charge drive beam to a lower-charge main bunch with high accelerating gradients. In this study, we propose an energy booster for the Compact Linear Accelerator for Research and Applications (CLARA) at Daresbury Laboratory, utilising dielectric wakefield acceleration (DWA). Our simulation study optimises the drive beam and structure to achieve maximal energy efficiency across varying main beam energies, enabling the delivery of a main beam with adjustable charge and final energy. Additionally, we have considered the stability of both the accelerated and drive beams, selecting the geometry and layout of accelerating structures to maximise accelerated beam quality and mitigate the development of beam breakup instability in the drive beam
Paper: TUPM087
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM087
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
TUPM092
Design studies on a kHz–MHz repetition rate pulsed muon source based on electron accelerator
1346
Certain types of muon experiments, such as muon spin rotation techniques and muon lifetime measurements, require beams with repetition rates around 50 kHz for optimal statistical performance. However, existing facilities are limited to pulsed beams operating at 25-50 Hz or continuous beams, both constrained by the time structure of proton drivers. Despite ongoing efforts to optimize these proton time structures, significant limitations in flexibility persist. This work introduces an alternative approach to muon production using high-repetition-rate (kHz-MHz) electron beams generated by superconducting linacs at XFEL facilities. This method provides unique temporal characteristics, promising substantial improvements in beam precision, flexibility, and experimental efficiency. We present comprehensive particle tracking simulations for the design of a surface muon beamline and detailed Monte Carlo studies to optimize target materials and geometries. The results underscore the potential of electron-driven muon sources to complement muon-based fundamental and applied physics research while extending the capabilities of current and future XFEL facilities.
Paper: TUPM092
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM092
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
TUPS005
Developing expectations for AWAKE with simulations
1393
The AWAKE experiment at CERN makes use of a self-modulated proton bunch to excite wakefields and accelerate a witness electron bunch. Run 2c of the experiment will demonstrate stabilization of the wakefield amplitude and control of the witness bunch emittance during injection and acceleration. In this work, we present an overview of the ongoing simulation efforts to support the project as it moves towards controlled acceleration and first particle-physics applications.
Paper: TUPS005
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS005
About: Received: 28 May 2025 — Revised: 30 May 2025 — Accepted: 30 May 2025 — Issue date: 06 Jun 2025
TUPS010
Electron beam scattering in rubidium vapour at AWAKE
1404
The Advanced Wakefield Experiment (AWAKE) at CERN uses bunches from the CERN SPS to develop proton-driven plasma wakefield acceleration. AWAKE Run 2c (starting in 2029) plans for external on-axis injection of a 150 MeV electron witness bunch. The goal is to demonstrate emittance control of multi-GeV accelerated electron beams. Prior to injection, the electron witness bunch may have to traverse rubidium vapour. Since the beam must have the correct beam size and emittance at injection, it is important to quantify the effect of scattering. For this, first-principle estimates and the results from Geant4 simulations are compared with measurements of a ~20 MeV electron beam scattering in 5.5 m of rubidium vapour, showing good agreement. Building on this agreement, Geant4 simulations using the estimated AWAKE Run 2c parameters are performed. These predict that scattering will not increase the electron beam size or emittance
Paper: TUPS010
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS010
About: Received: 31 Mar 2025 — Revised: 30 May 2025 — Accepted: 30 May 2025 — Issue date: 06 Jun 2025
TUPS011
Transverse tolerances in the plasma-wakefield acceleration blow-out regime
1408
We report on recent progress in transverse instabilities and transverse tolerances for plasma-wakefield accelerators in the blow-out regime. In this regime, the transverse fields provide both strong focusing and strong deflection via transverse wakefields. The deflection effect of the wakefields on the main beam leads to limitations on the acceleration efficiency, if not mitigated. Based on comprehensive particle-in-cell simulations we summarize recent findings of the instability--efficiency relation for the blow-out regime. Ion motion and energy spread may mitigate the instability; with linac start-to-end simulations, using the recently developed ABEL framework, we demonstrate that the instability and emittance growth may be sufficiently mitigated for the colliding beams in the HALHF concept. Independent of wakefield effects, the strong focusing fields lead to very tight tolerances for the drive-beam jitter. We quantify these tolerances, using examples from HALHF start-to-end simulations. We show that the tolerances are greatly loosened by applying external magnetic fields to guide the drive-beam propagation in the plasma.
Paper: TUPS011
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS011
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
TUPS012
ABEL: The adaptable beginning-to-end linac simulation framework
1412
We introduce ABEL, the Adaptable Beginning-to-End Linac simulation framework developed for agile design studies of plasma-based accelerators and colliders. ABEL’s modular architecture allows users to simulate particle acceleration across various beamline components*. The framework supports specialised codes such as HiPACE++, Wake-T, ELEGANT, GUINEA-PIG and CLICopti, which facilitate precise modelling of complex machine components. Key features include simplified models for addressing transverse instabilities, radiation reactions, and ion motion, alongside comprehensive diagnostics and optimisation capabilities. Our simulation studies focus on the HALHF plasma linac, examining tolerances for drive beam jitter, including effects of self-correction mechanisms. Simulation results demonstrate ABEL's ability to model emittance growth under transverse instability and ion motion, highlighting the framework’s adaptability in balancing simulation fidelity with computational efficiency. The findings point towards ABEL’s potential for advancing compact accelerator designs and contribute to the broader goals of enhancing control and precision in plasma-based acceleration.
Paper: TUPS012
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS012
About: Received: 27 May 2025 — Revised: 03 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
TUPS013
Ion-motion simulations of a plasma-wakefield experiment at FLASHForward
1416
In plasma-based acceleration, an ultra-relativistic particle bunch—or an intense laser beam—is used to expel electrons from its propagation path, forming a wake that is devoid of electrons. The ions, being significantly more massive, are often assumed to be stationary. However, both theory and simulations suggest that any sufficiently dense electron bunch can trigger ion motion, and its effect must be taken into account. We simulate beam-driven plasma wakefields to identify key features—such as longitudinally dependent emittance growth—that could be observed in an experiment using plasma and beam parameters from the FLASHForward facility at DESY.
Paper: TUPS013
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS013
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
TUPS017
Study on Ion Bunch Generation Using a Laser Plasma RF Ion Source
1420
The development of high-intensity, high-quality ion sources is essential for advanced applications such as particle beam therapy and nuclear physics experiments. The aim of this study is to integrate the Laser Plasma RF Ion Source (LaPRIS), currently under development, into the cyclotron at the Research Centre for Nuclear Physics (RCNP) in order to accelerate ion bunches with high precision and intensity for advanced applications. LaPRIS can generate laser-plasma in an RF field at the laser focus spot and produce bunches at arbitrary timings. Previous research* has achieved a proton beam with a peak current of 1.2 mA and a bunch width of 5 ns. This allows the charge per bunch to be increased by a factor of 100 compared to conventional systems. This makes it possible to track the beam behavior for each bunch, which has potential applications in high-intensity cyclotron research. The injection into the cyclotron must be matched to the acceptance, so the emittance of the beam bunches is measured under different laser characteristics and target conditions to investigate the beam properties.
Paper: TUPS017
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS017
About: Received: 02 Jun 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
TUPS020
Hands on training with ASTRA at ISBA'24
1432
As part of the program of the seventh International School on Beam Dynamics and Accelerators (ISBA'24), we carried out hands-on training with the accelerator simulation code ASTRA. A selection of students used the intensive two-hour daily course to go from learning the basics of ASTRA to designing and optimizing their own accelerators. Here we report the details of training, the student projects and their presentations to their instructors and peers, and plans for future hands-on training programs.
Paper: TUPS020
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS020
About: Received: 27 May 2025 — Revised: 30 May 2025 — Accepted: 30 May 2025 — Issue date: 06 Jun 2025
TUPS035
TURBO – Enabling fast energy switching for hadron therapy with constant magnetic fields
1469
The energy layer switching time is a limiting factor for hadron therapy, precluding fast beam delivery and reducing treatment efficacy. For rapid energy switching the beam delivery system must be achromatic with zero dispersion over a large energy range. At the University of Melbourne, the TURBO project will utilise Fixed Field Accelerator techniques to demonstrate transport of a ±42% momentum spread beam around a 30° bend, with constant magnetic fields to eliminate the energy switching bottleneck. This will be demonstrated with an electrostatic Pelletron accelerator. A fast-switching energy degrader with thin diamond films has been designed to quickly change proton beam energies in the range 0.5-3.0MeV, covering the full clinical range when scaled up. A new design technique using nonlinear magnetic fields for energy-dependent focusing has been developed to minimise delivered beam variations. A novel method has been found to produce nonlinear permanent magnet arrays without custom magnets, enabling fast prototyping and reuse of magnets. With these innovations, the TURBO project will demonstrate rapid energy switching for hadron therapy to enable improvements in patient outcomes.
Paper: TUPS035
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS035
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
TUPS036
Design and EM simulations of 750 MHz IH-DTL tank for carbon ion in medical applications
1473
This paper presents the design of 750 MHz IH-DTL (Interdigital H-mode Drift Tube Linac) tank, specifically developed to be part of a carbon ion injector for medical treatment applications. These sections provide a highly efficient solution for ion acceleration in the 5 to 10 MeV per nucleon energy range, offering a high shunt impedance. The study includes simulations of electromagnetic fields using CST Software, and beam dynamics simulations through a KONUS-type configuration
Paper: TUPS036
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS036
About: Received: 27 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
TUPS037
Simulation of RF components for the ICONE pilot: RFQ, rebuncher, DTL cavities and amplifiers
1477
CEA is committed to delivering a study for a warm linac in the frame of the ICONE project. It aims at accelerating an 80-mA beam of protons up to 25 MeV, with a 6% duty cycle. The LINAC consists of: a proton source with low-energy beam transport line, an RFQ, a medium-energy beam transport line, and a warm DTL. All these components must be tuned at 352.2 MHz, to reach the required output energy. This document presents the RF studies made by CEA and INFN on the main RF components, including the RFQ, the rebunchers, IH- and Alvarez DTL cavities and the RF amplifiers.
Paper: TUPS037
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS037
About: Received: 20 May 2025 — Revised: 01 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
TUPS038
Low energy beam transport line design for the Sarajevo ion accelerator
1481
The University of Sarajevo Physics Department, in collaboration with CERN’s Accelerator Beam Physics group, proposes a compact linear accelerator design for applied physics research spanning from beam dynamics studies to material surface analysis. The Sarajevo Ion Accelerator (SARAI) consists of an electron cyclotron resonance ion source, a low energy beam transport line (LEBT) and a radiofrequency quadrupole (RFQ). The ion source can produce an array of ions extracted with 30 kV. This study presents an iterative parameter optimization method that suggests two LEBT optics: one for beam diagnostics and another for compact beam matching to the RFQ acceptance. The RFQ discussed here is a 750 MHz, 2.5 MeV/u RFQ, used for medical applications. SARAI RFQ aims at 0.5 - 2 MeV/u. A novel RFQ technology allows a significant reduction in footprint. This paper further discusses plans for source commissioning and potential research applications.
Paper: TUPS038
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS038
About: Received: 27 May 2025 — Revised: 02 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
TUPS041
PEEK-Polymer as a vacuum-window in high power rf-couplers
1492
PEEK is an advanced polymer known for its exceptional mechanical strength, thermal stability, and radiation resistance, making it a promising candidate for applications in extreme environments. This study explores the viability of PEEK as a vacuum window material in high-power radio frequency (RF) couplers. Traditionally, materials such as ceramics are employed for this purpose; however, they are costly to manufacture and impose limitations during the design process. PEEK offers additional advantages, including the possibility of additive manufacturing, which enables the integration of cooling channels for efficient thermal management. The research evaluates PEEK's electrical, thermal, and mechanical properties under conditions typical of high-power RF couplers, such as vacuum stability, RF-induced heating, and electromagnetic transparency. At the Institute for Applied Physics (IAP), PEEK is tested as a vacuum window material in high-power experiments up to 35 kW. Following these tests, the material is analyzed to assess its performance and suitability for RF applications.
Paper: TUPS041
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS041
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
TUPS049
Low-power test of bridge coupler in disk-and-washer structure for muon acceleration
1509
A muon linear accelerator is under development at J-PARC for precise measurement of the muon anomalous magnetic moment (g-2) and electric dipole moment (EDM). A disk-and-washer (DAW) structure is employed to accelerate muons from 30% of the speed of light (kinetic energy = 4 MeV) to 70% (40 MeV) at 1296 MHz. The muon DAW consists of tanks accelerating the muons and bridge couplers that couple the tanks and focus the beam using an internal quadrupole doublet. A bridge-coupler prototype is currently being fabricated and will be tested. This paper presents the design and performance evaluation of the bridge coupler prototype.
Paper: TUPS049
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS049
About: Received: 07 Apr 2025 — Revised: 30 May 2025 — Accepted: 31 May 2025 — Issue date: 06 Jun 2025
TUPS051
Avoiding overcooled ion beams by exciting energy spread through electron cooling
1517
Ion accelerators use electron cooling to improve luminosity and beam lifetime. However, extremely low momentum spread in a cold beam weakens Landau damping, enabling the development of instabilities and potentially decreasing lifetime. To combat this, the NICA Booster electron cooling system allows to generate electron beams with oscillating energy to increase the momentum spread in ion beams. Here we describe the implementation of the energy oscillation technique and provide numerical calculations predicting the achievable momentum spread.
Paper: TUPS051
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS051
About: Received: 27 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
TUPS054
Optimization of a multichannel solid state plasma for laser wakefield acceleration with realistic laser parameters using a Bayesian algorithm
1523
Nanostructures based on carbon nanotube arrays are emerging as promising media for achieving ultra-high acceleration gradients in laser wakefield acceleration (LWFA). In this study, we design and optimize plasmas with hexagonal lattice structures, where the lattice parameters directly define the nanostructure's properties. Using WarpX, a state-of-the-art particle-in-cell (PIC) simulation framework, we conduct fully three-dimensional simulations to model the interaction between these advanced plasmas and laser pulses. To refine the lattice parameters, we apply Bayesian optimization through the Python library BoTorch, identifying optimal configurations for generating effective wakefields. These results are intended to guide preliminary simulations for future experiments at leading laser facilities, such as ELI and VEGA3, advancing the exploration of LWFA with nanostructured plasmas.
Paper: TUPS054
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS054
About: Received: 16 May 2025 — Revised: 31 May 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
TUPS055
Simulations study of transverse wakefields in a dielectric wakefield acceleration scheme
1527
Novel acceleration schemes aim to address the need for higher acceleration gradients which enable to minimise the size and costs of particle accelerators. One of these novel accelerator schemes is the dielectric wakefield acceleration (DWA), where an electron bunch is accelerated by the longitudinal wakefields generated within a dielectric lined waveguide by a leading drive bunch with higher charge. The advantages of this novel acceleration method include high accelerating field strength, the simplicity of its structure and the stability of the wakefield generated which is synchronous with the electron bunch. However, the drive bunch propagation length, and hence the achievable energy gain, is limited by the effect of the transverse wakefields. These fields deflect the bunch towards the dielectric, leading to charge losses, a phenomenon commonly referred to as beam break-up (BBU) instability. This study uses simulations to investigate the transverse wakefields and their impact on the beam dynamics in a DWA scheme with drive and witness (main) bunches. The findings will be further explored experimentally at the CLARA facility in Daresbury Laboratory.
Paper: TUPS055
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS055
About: Received: 23 May 2025 — Revised: 02 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
TUPS071
Theoretical models for CsTe thin film semiconductor photocathodes at high electromagnetic fields
1553
Understanding performance and limitation of CsTe photocathodes under high field gradients in a radio-frequency gun requires adequate theoretical models for material properties, photoemission and surface morphology. We are developing a suite of models based on Density Functional Theory (DFT), moment and Monte-Carlo (MC) photoemission models, and meso-scale material surface model informed by DFT and Molecular Dynamic (MD) simulations. Our DFT calculations provide detailed structural, elastic, electronic, optical, and transport properties of CsTe for photoemission applications. Temperature, density of states, and thin film optical effects have recently been incorporated in a moment-based photoemission model, while the high field effects for electron transport and emission are being modeled in the MC model. Our meso-scale surface model addresses surface morphology under high field stress and surface heating. Machine-learning technique has also been used to enhance the DFT and MD calculations for CsTe. This poster will present an overview of these theoretical models and their results with applications to the LANL CARIE project and other relevant experiments.
Paper: TUPS071
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS071
About: Received: 28 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
TUPS089
Helical undulators assembled from magnetized ring sectors
1559
Undulators assembled from quasi-helices consisting of readily available magnetized ring rare-earth sectors are proposed. "Radially" magnetized sectors create a stronger field on the axis than longitudinally magnetized ones. The field value weakly depends on the number of sectors per undulator period. An experimentally studied prototype Halbach-type helical undulator of "radially" and longitudinally magnetized quasi-helices consisting of ring NdFeB sectors with a period of 2 cm and a comparatively large inner diameter of 8 mm provides a field of about 0.6 T on the axis. By reducing the inner diameter to 5 mm, it is possible to obtain a field twice as large. When assembling such an undulator, it is convenient, while maintaining the positions of all ring sectors, to use a division of the undulator not into quasi-helices, but into cylindrical sectors shifted along the axis and rotated relative to each other. Permanent undulators from ring sectors can provide a higher velocity of transverse electron oscillations than planar ones, and therefore seem promising for increasing the efficiency of FELs in various frequency ranges.
Paper: TUPS089
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS089
About: Received: 14 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
TUPS092
Wakefield studies of the taper section of the elliptical in-vacuum undulator - IVUE32
1562
The elliptical in-vacuum undulator (IVU) IVUE32 is being developed at Helmholtz-Zentrum Berlin (HZB). The APPLE-II design allows for not only gap changes but also longitudinal shift movements, putting additional design challenges on the tapers at the entrance and exit of the undulator. The chosen design philosophy separates the gap and shift movement compensation into two assemblies respectively. This approach allows for a solid foil taper as gap movement compensation, which is proven in previously commissioned planar IVUs e.g. CPMU17 at HZB. The shift movement compensation, which requires a slit foil, can be kept parallel. The proximity of this complex structure to the electron beam makes the device susceptible to wakefield effects which can influence beam stability. Investigating and understanding these effects is vital for accelerator operation. The taper design will be presented alongside wakefield simulations and model measurements.
Paper: TUPS092
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS092
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
TUPS094
Diagnosing an In-Vacuum Undulator in the ALS storage ring
1569
The Advanced Light Source (ALS) has an in-vacuum undulator named “LEDA”. It was installed in 2019 and provides high-brightness, high-energy photons for the ALS macromolecular crystallography beamline, Gemini. The undulator is a hybrid design with a minimum gap of 4.3 mm, a magnetic period of 15 mm, and a photon energy range of 5–19 keV. When the device was commissioned in the ALS storage ring, it had a negligible impact on ring operations. Recently, there has been a measured degradation in storage ring performance correlated with the Leda gap. Prior to conducting an invasive magnetic measurement, we performed a suite of beam-based measurements to characterize Leda. Herein, we detail these measurements and share them with the accelerator community, who may find them useful when encountering similar challenges.
Paper: TUPS094
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS094
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
TUPS110
Implementation of novel acceleration functionality in BDSIM
1572
Beam Delivery Simulation (BDSIM) is a Geant4 based accelerator tracking code which includes interactions of particles with material. BDSIM has become an important code in the accelerator community to simulate beam lines. Since laser and beam driven plasma wakefield acceleration (LWFA/PWFA) is a promising acceleration method we found it important to include related capability in BDSIM. This requires the addition of new beamline elements that are commonly used in plasma acceleration experiments. A gas volume where the LWFA/PWFA takes place and a beam mask to create a separate drive beam and a witness beam. In the former, the beam interacts with gas so ideal gas calculations are required to input the gas properties. Biasing can specifically be applied to the gas material in those elements. Simulating the interactions between the beam and a plasma is not done in BDSIM. An external software is used to compute the fields and the particles data. BDSIM can now read the output HDF5 files to reconstruct the fields inside the gas capillary or use the particle data as a bunch definition for the beginning of a beamline. Some results explaining how to make a LWFA/PWFA simulation are presented.
Paper: TUPS110
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS110
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
TUPS128
Simulations of ion bombardment in thermionic cathode RF guns
1590
Thermionic cathodes are well known as a robust source of electrons for a wide range of accelerator applications. In the case of Barium Oxide cathodes the low work function that allows emission at modest temperatures is achieved through a surface coating. This coating can be damaged from both ion bombardment and, in the case of RF sources, electron bombardment. Lifetime models that predict the dynamics of these coatings are based on DC electron guns. Understanding the dynamics of ion bombardment in thermionic RF electron guns and under operational conditions is paramount to understanding cathode lifetime and optimizing performance. In this paper we simulate the generation of ions through impact ionization in the APS electron gun. We then compute the energy distribution of ions deposited on the cathode and effective ionization cross section as we vary operational conditions. These simulations are compared with analytical calculations based on first principles.
Paper: TUPS128
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS128
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
TUPS140
Design of Pelletron accelerator using novel accelerating tube without gap insulators
1608
A novel modular electrostatic accelerating tube*, free from gap insulators, is designed that addresses the limitations of traditional metal-insulator bonded accelerating tubes**, which are costly and prone to damage from high-voltage discharges and beam impacts. This design uses ultra-high vacuum (UHV) as the insulator, with electrodes placed in series under vacuum. High voltage is coupled longitudinally to the first cylindrical electrode via a ceramic-bonded stainless steel flange, with homogeneous electric field flatness of 0.001. Electrostatic analysis using COMSOL Multiphysics and TRAVEL code confirms the field homogeneity and smooth beam acceleration, respectively. Designed for 75 kV operation, extendable to q×100keV energy gains, it leverages vacuum-compatible resistors for inter-electrode HV coupling. Field flatness is extendable to few meters of length and thus enabling megavolts. Beam optics and electrical specifications for Pelletron accelerators using these tubes supports practical feasibility. The grounded cylindrical structure ensures safety and offers an economical, scalable design for small low-energy implanters, Pelletron accelerators, and mass spectrometers.
Paper: TUPS140
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS140
About: Received: 29 May 2025 — Revised: 01 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
WEBD3
Integrating permanent magnets and electromagnets: a hybrid dipole magnet design
1664
In this study, we designed a hybrid dipole magnet that integrates both permanent magnet and electromagnet technologies. The primary magnetic field is generated by the permanent magnets, while the coils enable fine-tuning of the field. The design carefully considers the placement of the permanent magnets and coils to optimize performance. Additionally, an outer plate mechanism is incorporated for coarse magnetic field adjustments, and a NiFe compensator is employed to mitigate the effects of temperature variations on the magnetic field. Given the challenges and risks associated with assembling strong magnets, we also developed a detailed assembly procedure and a set of specialized fixtures to ensure safe and efficient assembly. The integration of permanent and electromagnetic technologies in this hybrid design provides a robust and adaptable solution, paving the way for innovative applications in advanced accelerator technologies.
Paper: WEBD3
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEBD3
About: Received: 27 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
WEBN1
Empowering a broad and diverse community in beam dynamics simulations with Xsuite
1667
Xsuite is a Python toolkit for modelling and simulation of particle accelerators, which has been developed at CERN together with collaborators from other institutes over the past four years. The code has reached a mature development stage and has become the workhorse for several studies and applications, allowing the gradual replacement of legacy tools like Sixtrack, COMBI, PyHEADTAIL. This contribution provides an overview of the code capabilities and illustrates examples in different areas of accelerator science, including low-energy hadron rings for medical applications, high-intensity hadron accelerators, synchrotron light sources, high-energy hadron and lepton colliders.
Paper: WEBN1
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEBN1
About: Received: 26 May 2025 — Revised: 30 May 2025 — Accepted: 01 Jun 2025 — Issue date: 06 Jun 2025
WEBN2
A module for fast auto differentiable simulations
1671
The auto differentiable simulation is a type of simulation that outputs of the simulation contain not only the simulation result itself, but also its derivatives with respect to many input parameters. It provides an efficient method to study the sensitivity of the simulation result with respect to the input parameters and can be used in some gradient based optimization methods for fast parameter design optimization. In this paper, we report on the development of a fast auto differentiation module that can be used in many simulation codes.
Paper: WEBN2
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEBN2
About: Received: 20 May 2025 — Revised: 30 May 2025 — Accepted: 01 Jun 2025 — Issue date: 06 Jun 2025
WEPB009
Superconducting β=0.19 half-wave cavity for CiADS
1703
A 162.5 MHz, optimal beta = 0.19 pure niobium half-wave resonator (HWR) called HWR019 for the superconducting driver linac of the China initiative Accelerator-Driven subcritical System (CiADS) has been designed and analyzed at the Institute of Modern Physics, Chinese Academy of Sciences (IMP, CAS). The linac requires 24 HWR019s to accelerate protons from 6.8 MeV to 45 MeV. This paper mainly presents a design scheme of HWR019. Meanwhile, electromagnetic field optimization, and mechanical structure design are carried out, to predict the behavior of the cavity under practical operating process. At present, this superconducting cavity has been fabricated a prototype and awaits further testing.
Paper: WEPB009
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB009
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
WEPB010
RF design for a quadrupole resonator with a fundamental frequency of 325 MHz at IMP
1706
The Quadrupole Resonator (QPR), originally developed at CERN, is a dedicated radio-frequency characterization equipment for evaluating superconducting material. It employs the calorimetric compensation technique and has a surface resistance resolution of less than 1 nOhm, operaing over a wide range of parameters, such as tem-peratures, resonant frequencies and magnetic fields. As a part of R&D work of superconducting material for SRF application in particle accelerators. A QPR with operating frequency of 325 MHz has been developing at Institute of Modern Physics (IMP), CAS. In this paper, we present the detailed electromagnetic design of the QPR, the design focuses on reducing the risk of multipacting, field emis-sion (B<sub>pk</sub>/E<sub>pk</sub>) and mode overlapping (delta f = f<sub>QPR</sub>-f<sub>dipole</sub>), enhancing the attainable peak magnetic field (B<sub>sample</sub>/B<sub>pk</sub>). The electromagnetic simulation results indicate that the optimized structure has good electromagnetic performance. Additionally, the coupler design compatible with four QPR modes will be introduced. The cavity will be fabricated soon.
Paper: WEPB010
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB010
About: Received: 09 Apr 2025 — Revised: 31 May 2025 — Accepted: 31 May 2025 — Issue date: 06 Jun 2025
WEPB015
Multicell parameterisation for sensitivity analysis and uncertainty quantification of elliptical accelerator cavities
1718
Elliptical cavity geometries are typically parameterised using a canonical set of variables that define the shape of the cavity half-cells. In multicell cavity optimisation, the mid-cells are modelled with identical dimensions, while the end-cells are optimised to ensure good field flatness. However, manufacturing tolerances can introduce slight variations between individual half-cells, as cavities are produced with separate dumb-bells, which are thereafter welded together. To address these variations, a multicell parameterisation is proposed, where each half-cell is defined by its own set of variables. This parameterisation method offers a more accurate representation of real-world cavity geometries and facilitates a detailed analysis of the impact of geometric uncertainties on cavity performance. A sensitivity analysis is presented to quantify the influence of each independent geometric variable on key performance metrics, providing valuable insights for optimising both cavity design and manufacturing processes.
Paper: WEPB015
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB015
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
WEPB023
Transitional solution of solid-state power amplifier at NSRRC
1734
The Taiwan Photon Source (TPS) of the National Synchrotron Radiation Research Center (NSRRC) in Taiwan has integrated Solid-State Power Amplifiers (SSPAs) into routine operations since 2023, supporting a stored beam current of 500 mA. In response to the phasing out of Ampleon's BLF578 and the growing demand for improved energy efficiency, a new SSPA was developed based on the existing module configuration, utilizing the BLF978P as an interim solution. This approach serves as a bridge while the development of the next-generation SSPA, employing GaN transistors, is still underway. Both SSPA configurations, with and without circulators, were explored during development. This paper presents the performance of the prototypes and the implementation details.
Paper: WEPB023
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB023
About: Received: 28 May 2025 — Revised: 31 May 2025 — Accepted: 31 May 2025 — Issue date: 06 Jun 2025
WEPB030
Efficient nonlinear simulations of the fast corrector magnets for PETRA IV
1760
Fast orbit feedback systems are an important component in fourth-generation synchrotron radiation sources such as PETRA IV at DESY in Hamburg, Germany. These control systems are designed to stabilize the particle orbit, i.e., to correct deviations from the design orbit due to various disturbances. To that end, such a system employs fast orbit corrector magnets, which must be powered at frequencies up to the kilohertz range. This leads to significant eddy current effects that must be predicted via finite element simulations. Therefore, extensive simulation studies have already been conducted. These simulations did not, however, consider the magnetization curve’s nonlinearity since doing so requires prohibitive computational effort when using commercial software. Hence, we have constructed a dedicated method, based on a combination of the harmonic balance finite element method and homogenization schemes, to enable nonlinear simulations. This contribution outlines the general idea and application of our method to the corrector magnets of PETRA IV and presents the most important findings regarding the impact of the nonlinear magnetization curve on the magnet’s performance.
Paper: WEPB030
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB030
About: Received: 05 May 2025 — Revised: 30 May 2025 — Accepted: 30 May 2025 — Issue date: 06 Jun 2025
WEPB034
Beam impact experiment to qualify the damage limits of Nb3Sn sample coils pre-irradiated to 30 MGy
1764
A series of experiments has been carried out at CERN to derive the damage limits of superconductor strands and sample coils. The latest experiment was designed to characterize the limits of Nb3Sn racetrack sample coils impacted by a 440 GeV/c proton beam at cryogenic temperature. The effect of a beam impact on superconducting coils aged by long-term radiation exposure, however, is currently unknown. This paper outlines the preparation of an experiment to be performed at the HiRadMat facility to investigate the damage on coils which have been aged with X-rays to simulate the anticipated integral dose levels reached by the HL-LHC final focusing magnets during their operational lifetime, of 25 to 30 MGy. The damage limits for these coils will be derived and compared with the results previously obtained for non-aged coils. The design and fabrication of these sample coils, the details of the X-ray irradiation and the results from their qualification tests before beam impact is discussed. The results of energy deposition simulations that define the optimal parameters for the proton beam to be used are presented. The experimental setup and procedure are discussed.
Paper: WEPB034
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB034
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
WEPB038
Magnetic circuit design and consideration for HTSW using 12mm HTS tape
1779
The National Synchrotron Radiation Research Center (NSRRC) is focused on the application of 2G high-temperature superconducting tape (2G-HTS) for the insertion device in the Taiwan Photon Source (TPS) synchrotron ring. A preliminary design for a 2G-HTS wiggler (HTSW) is being developed, with considerations for sharing the SRF straight-section to make efficient use of space. The target field strength of the HTSW is 3.5 T, chosen to avoid increasing electron beam emittance. The HTSW is also designed to operate using a cryogen-free cryostat with a cryocooler to reduce liquid helium consumption. Safety margins for the current density applied to the HTS tape have been considered to prevent quenching during operation. Various parameters of the HTSW have been optimized and discussed to meet operational requirements, and a set of suitable parameters for HTSW in TPS is presented in this letter.
Paper: WEPB038
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB038
About: Received: 16 May 2025 — Revised: 29 May 2025 — Accepted: 31 May 2025 — Issue date: 06 Jun 2025
WEPB052
The impact of insertion devices on Solaris storage ring optics
1812
This study investigates the influence of insertion devices (IDs) on the optical properties of the Solaris electron storage ring through a combination of experimental measurements and simulations. The effects of various ID settings were analyzed using tune measurements and the Linear Optics from Closed Orbits (LOCO) method. These results were compared with simulations performed using the Python Accelerator Toolbox (pyAT). Furthermore, a Long Short-Term Memory (LSTM) neural network was developed and tested for forecasting corrector magnet currents associated with the IDs. Diagnostics included monitoring the electron beam in the storage ring and photons delivered to beamlines. Additionally, the performance of both slow and fast orbit correction systems in response to ID-induced perturbations was assessed. This work provides insights into ID impact on beam dynamics and highlights the potential of machine learning for predictive control in accelerator systems.
Paper: WEPB052
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB052
About: Received: 26 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
WEPB054
Advanced power density mapping for FEA simulations of synchrotron accelerator high heat load components
1815
Accurately simulating the thermal and mechanical effects of undulator power density distribution in high heat load components requires precise power implementation in finite element analysis (FEA) models. This study presents a novel methodology utilizing intermediate programming to efficiently map complex undulator power density distributions onto FEA models. The approach enables the placement of power density values (e.g., W/mm²) on each element surface while simultaneously calculating the grazing angles based on the insertion device's power source geometry. By automating these processes, the methodology significantly reduces the time and effort required for engineers to implement detailed power distributions in FEA simulations. This advancement not only ensures higher accuracy in modeling but also streamlines the workflow, allowing for faster evaluation and optimization of high heat load components in synchrotron radiation facilities. The proposed framework offers a practical solution for integrating advanced undulator power profiles into engineering analyses, enhancing both efficiency and reliability.
Paper: WEPB054
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB054
About: Received: 07 May 2025 — Revised: 30 May 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
WEPB060
Stripline kicker design for FCC-ee booster injection and damping ring
1833
The FCC-ee booster injection kicker, will be injecting 4 particles bunches per single kick. The bunch separation in the booster ring is 25 ns and therefore requiring a faster kicker rise and fall time to not perturb injected or already circulating bunches. The wakefield impedance of the stripline is also important to not perturb the stored beam as well as it is necessary to ensure a good integrated fields and field homogeneity for kicking the bunches. The major challenge is to provide a precise impedance matching along the entire path of the electric pulse from the generator to the stripline termination. Transmission line cables, connectors and feedthroughs may already distort the pulse. 3D model of the stripline magnet including the high voltage connectors and simulation model of cables and generator was designed. It is shown that the results of the stripline magnet simulations meets the requirements, but the design of the entire system will need to be supplemented by research into active compensation for cable pulse distortion. The results are discussed in terms of validity due to assumed component parameters and ideas for benchmarking on a laboratory prototype are outlined.
Paper: WEPB060
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB060
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
WEPB061
High repetition tests of a pulsed power supply using SiC-MOSFETs for a fast kicker system in KEK-PF
1837
A pulsed power supply (PPS) using SiC-MOSFETs is an essential component in the camshaft-bunch system at KEK-PF *. The system requires the PPS to generate half-sine pulses with a peak current of 500 A, a pulse width of 200 ns, and a repetition rate (rep-rate) of 800 kHz. We have developed a prototype PPS consisting of a resonant circuit (RC) to generate half-sine pulses with a SiC-MOSFET switching module (SWM). The SWM, manufactured by NexFi Technology, has a rated voltage of 24 kV and a maximum rep-rate of 400 kHz. The main challenges in RC development were to reduce the charging time of the RC and power consumption during high-frequency operation. Additionally, film capacitors used in a previous prototype * required replacement because their permittivity had degraded during high-frequency operation. To overcome these challenges, we designed a RC with an energy recovery circuit, which reduced the charging time to 1 µs and power consumption by 90%. To ensure reliability, the film capacitors were replaced with vacuum capacitors. This report presents the prototype design, performance tests at a rep-rate of 400 kHz, and evaluation of long-term reliability at a rep-rate of 100 kHz.
Paper: WEPB061
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB061
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
WEPB083
The cavity combiner development for TPS SSPA tower at NSRRC
1869
NSRRC builds four home-made solid state power amplifier towers to provide 300 kW for one superconducting RF cavity at TPS. The power combining tree of one tower is two-stages structure with a complex wire connection. In order to simplify the wire connection and increase the power combining efficiency, we devote resources to develop the cavity combiner. In this study, a 21-ports cavity combiner is designed and manufactured. The RF properties, S11 and S21, of output port were simulated and measured to evaluate the combining efficiency.
Paper: WEPB083
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB083
About: Received: 29 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
WEPB113
Design of an online adjustable waveguide coupler for the TM020-mode cavity of proposed STCF
1901
The Super Tau-Charm Facility (STCF) project plans to use 12-15 TM020-mode cavities for each collider ring to compensate for the beam energy loss. Each cavity is designed to provide a voltage of 0.5 MV and a power of 250 kW for the beam. Therefore, an online adjustable waveguide coupler with a power capacity of CW 300 kW has to be developed for each cavity. This input coupler has a waveguide size the same as the half-height WR1500. The coupling between the cavity and the half-height WR1500 is realized by a rectangle hole with blending. This paper presents the electromagnetic design, the multipacting simulation, and the thermal and stress analysis of the input coupler in detail.
Paper: WEPB113
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB113
About: Received: 27 May 2025 — Revised: 30 May 2025 — Accepted: 01 Jun 2025 — Issue date: 06 Jun 2025
WEPM006
Optics optimization and commissioning simulations for Elettra 2.0
1917
Optimization of dynamic aperture is a challenging aspect of low emittance storage ring lattice design. A large dynamic aperture is favourable for efficient injection and long beam lifetime. Several methods like simple scanning of sextupoles and octupoles strength and genetic optimization with different configurations have been successfully combined to enlarge the dynamic aperture of Elettra 2.0 and ensure high efficiency injection. Using the optimized machine we then study its commissioning via simulations including and discussing the various stages from injection to the first turn, to accumulation.
Paper: WEPM006
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM006
About: Received: 27 May 2025 — Revised: 03 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
WEPM010
Beam-based beam-beam benchmarking and correction
1925
Optics studies in the LHC are generally performed on low-intensity, non-colliding beams. Understanding the optics perturbation from beam-beam effects however, is of significant interest. This was particularly true for the LHC in 2024, where the 3Qy resonance driven by the long-range beam-beam (LRBB) contributed to breaking of the collimator hierarchy, limiting beta* reach and luminosity. By performing optics measurements on a low-intensity bunch in collision with a nominal train, it has been possible for the first time to directly measure the optics perturbation from LRBB in the LHC. Benchmarking of the beta-beat and resonance driving terms against simulation shows good agreement. Based on these models, it was possible to find corrections for the LRBB driven 3Qy resonance using the skew-sextupole correctors present in the LHC.
Paper: WEPM010
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM010
About: Received: 27 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
WEPM012
Status of the CERN optics measurement and correction analysis tools
1929
With a change in the LHC machine optics foreseen for 2025 and the possible reduction of beta-star, optics commissioning will become even more of a challenge for the CERN Optics Measurement and Correction (OMC) team. In particular, the increased sensitivity of the optics to non-linear imperfections, requiring a plethora of accurate measurements, is expected to be a time consuming task. In preparation, continuous effort has been undertaken to develop new correction strategies and convert them into ready-to-use algorithms, allowing the automation of repetitive tasks while keeping the python-base software tools up-to-date. In this paper the status of these tools is summarized with highlights and improvements underlined. These tools are now widely used beyond the LHC in the entire CERN accelerator complex, as well as in Super-KEKB and for Future Circular Collider studies, and could be of great interest to correct and improve the optics in other machines.
Paper: WEPM012
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM012
About: Received: 26 May 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
WEPM014
Impact of linear imperfections in the high luminosity LHC separation dipole magnets
1937
Magnetic field measurements have been performed after fabrication of new separation dipoles for the low beta-star insertion regions of the High Luminosity LHC project*. In this paper, the effect of the linear imperfections of these magnets on coupling, beam size and beta-beating are evaluated using MAD-X simulations. The results indicate that the impact of normal-oriented quadrupole errors are small and easily correctable, while for skew-oriented quadrupole imperfections corrections require a significant fraction of the arc skew quadrupoles strength. Subsequent simulation studies were therefore performed to devise potential mitigation strategies, the results of which are also reported here.
Paper: WEPM014
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM014
About: Received: 26 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
WEPM016
Benchmarking of LHC beam intensity dependent transverse tune corrections at injection energy
1945
Observations of betatron tune evolution during LHC beam injection have revealed a significant tune error, strongly correlated with beam intensity. This finding highlights limitations in the existing feedforward corrections based on Laslett coefficients. A dedicated machine development study was conducted to refine intensity-dependent tune corrections. Utilizing high-precision, per-bunch tune measurements facilitated by the LHC transverse feedback system, the study characterized tune shifts under varying intensities and beam conditions. The results uncovered pronounced discrepancies between horizontal and vertical planes, which deviate from predictions made by the current correction model. These insights provide a critical foundation for improving the accuracy of intensity-dependent tune adjustments, impacting operational stability and efficiency, in particular when considering future operation of the high-luminosity LHC.
Paper: WEPM016
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM016
About: Received: 23 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
WEPM018
Optimizing beam-beam beta-beating for luminosity enhancement at the LHC
1949
The optimization of LHC operation is focused on achieving the highest possible integrated luminosity to maximize experimental data collection. Given the limitations of current detector systems, maintaining a constant level of integrated luminosity has become more critical than achieving a high peak luminosity. Techniques such as beta-leveling and separation levelling have already been implemented to adjust luminosity and enhance operational efficiency. This study describes how the beam-beam beta-beating effects propagating between the multiple experimental interaction points can serve as an additional mechanism to further increase the total integrated luminosity. The operational solutions and impact on performance will be shown for both the current LHC and its future High Luminosity upgrade.
Paper: WEPM018
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM018
About: Received: 23 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
WEPM019
Data driven methods to recognize patterns in EIC weak-strong simulation
1953
Beam-Beam simulations are currently being studied in preparation for future EIC experiments to study beam-beam effects and, in turn, maximize luminosity. Weak-strong methods are studied for single-particle dynamics during collision. 1 million macro-particles for 1 million turns are typically tracked, corresponding to only 10 seconds in the EIC. The goal of this study is to predict beam properties over the scale of hours. A potential solution focuses on using data-driven methods such as machine learning methods to analyze and extend the insights of the beam properties such as long-term nonlinear effects. This would aid in long-term predictions where results would be more efficiently acquired than a typical tracking simulation. Some limitations such as inaccurate predictions and spatial complexity are also discussed. These methods can then be applied to strong-strong simulations in the future studies.
Paper: WEPM019
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM019
About: Received: 28 May 2025 — Revised: 01 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
WEPM026
Study of an anomalous beam profile in the Compact ERL’s injector at KEK
1969
The cERL injector objective is to produce and deliver a high-quality electron beam to the recirculation loop. However, a recent observation of an anomalous "triangle beam" profile just after the first solenoid presents significant challenges. This distorted beam profile can lead to inaccurate parameter measurements, reduced focusing and collimation efficiency, and increased sensitivity to injector errors. This study investigates potential causes, including hexapole field components, misalignment, nonlinearity of air-core steering, and beam kick at cathode. Machine learning techniques are employed to analyze experimental data and simulation results to identify the primary factors. Based on these findings, potential solutions to mitigate the "triangle beam" issue and optimize injector performance are proposed.
Paper: WEPM026
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM026
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
WEPM030
Beam optics simulations of achromatic section of Delhi Light Source
1981
The Delhi Light Source is an upcoming user facility for coherent THz radiation and electron beam. Electron beam of energy upto 8 MeV generated from a RF photo-cathode gun will be used for coherent THz generation from a planer undulator. The beam after passing through the undulator field will be separated from the THz and THz line by a $60^{o}$ achromatic section and delivered to electron experimental area. Simulation studies has been performed to achieve achromatic condition and acceptable beam size at the electron experimental area for the case of electron transmission through non-trivial undulator field. However for the case of open gap undulator (no THz generation), the study shows that the same design gives a limited control on the overall beam size at the electron experimental area. To overcome this the extended quadrupole correction (EQC) coils of the undulator can be used as a suitable focussing element to achieve required beam size control in addition to the achromatic condition. The paper presents the simulation studies of the achromatic section for both with and without(open gap) undulator field.
Paper: WEPM030
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM030
About: Received: 20 May 2025 — Revised: 30 May 2025 — Accepted: 01 Jun 2025 — Issue date: 06 Jun 2025
WEPM031
Simulation-based optimization of the injection of ultrashort non-Gaussian electron beams into a storage ring
1985
The compact STorage ring for Accelerator Research and Technology (cSTART) project at the Karlsruhe Institute of Technology (KIT, Germany) aims to explore non-equilibrium electron beam dynamics and injection of laser-plasma accelerator (LPA) bunches. The Very Large Acceptance compact Storage Ring (VLA-cSR) is also filled by a second injector that delivers ultra-short bunches from the Ferninfrarot Linac- Und Test-Experiment (FLUTE). Injection from FLUTE into the VLA-cSR is achieved via a complex 3D injection line featuring tilted deflections, negative dispersion, and extreme compression to femtosecond bunch lengths. From this transport, the bunch develops pronounced non-Gaussian tails; nevertheless, near the injection point, it is crucial to ensure matching to both the dynamic aperture and the periodic solutions of the storage ring dynamics. The 25 quadrupole magnets of the injection line make conventional optimization methods impractical. This contribution discusses the development of the magnet optics to meet these extreme requirements. The optimization task was divided into two parts: longitudinal compression was addressed using a surrogate model, while transverse matching is currently being pursued with Bayesian optimization.
Paper: WEPM031
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM031
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
WEPM033
Energy ramping simulation for TPS booster ring
1993
The Taiwan Photon Source (TPS) booster ring accelerates electron beams from the linear accelerator (lin-ac) output energy of 150 MeV to 3 GeV for storage ring injection. In the event of partial RF station failure in the linac, the available beam energy may be reduced to 100 MeV. Preliminary machine tests have demonstrated multi-turn beam circulation in DC mode and successful acceleration from 127.5 MeV to 3GeV. Beam dynamics simulations using elegant evaluate the effects of dipole field errors, magnet multipole and alignment errors, chamber aperture constraints. Additionally, space charge effects at 100 MeV, due to the low relativistic factor, could lead to incoherent tune shifts, and potential beam loss. This study investigates the feasibility of operating the TPS booster at 100 MeV injection and ramping to 3 GeV with a focus on beam dynamics considerations
Paper: WEPM033
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM033
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
WEPM034
Beam optics model and characterization for CERN's low-energy ISOLDE transfer lines
1997
The PUMA (antiProton Unstable Matter Annihilation) experiment at CERN aims to explore the interaction of antimatter with exotic isotopes, utilizing the unique capabilities of CERN’s ISOLDE facility and Antiproton Decelerator. This contribution presents recent advancements in the beam transfer lines optics studies relevant to the success of the experiment, and to ISOLDE’s operation in general. A detailed beamline model has been developed using MAD-X and XSUITE, including the consideration of apertures and alignment errors. Quadrupole scans and kick response measurements have been employed to build and benchmark the model. In addition, tomographic reconstruction was tested, aiming to obtain a detailed characterisation of the beam's transverse phase space. A distinctive feature of ISOLDE’s beamlines is the use of electrostatic, rather than magnetic, quadrupoles. To address this, an electrostatic quadrupole model was developed and benchmarked using CST. These promising results validate the optics model, demonstrating its potential to improve beam delivery across the Low-Energy ISOLDE facility and contributing towards the PUMA experiment's operational readiness.
Paper: WEPM034
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM034
About: Received: 26 May 2025 — Revised: 31 May 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
WEPM038
Alignment tolerance studies for the cSTART storage ring
2008
The KIT cSTART project (compact STorage ring for Accelerator Research and Technology) aims to demonstrate the injection and storage of a high intensity ultra-short electron bunch in a large acceptance storage ring using the FLUTE linac and a laser plasma accelerator (LPA) as injectors. Amongst the unique features of the cSTART project is the wide dynamic range of machine and beam parameters to be employed, i.e. bunch charge, bunch length, beam energy, etc. The comparably low energy beam (40-90 MeV) will be injected on-axis and will be stored for about 100 ms without reaching equilibrium due to the absence of significant radiation damping. In order to ensure stable operation of the storage ring, we need to specify tolerable magnetic lattice misalignments and understand the impact on the beam dynamics to be able to implement adequate correction schemes. In this paper, we report on first studies and simulation results on the effects of magnet misalignment, roll angles, and field errors on the dynamic aperture and momentum acceptance of the cSTART storage ring and propose a suitable correction strategy.
Paper: WEPM038
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM038
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
WEPM039
Effects of tracking errors on the SOLEIL II booster
2012
For the upgrade of SOLEIL II a new booster with reduced transverse and longitudinal beam sizes is required. The new booster follows a 16 BA Higher-Order Achromat lattice with a reduced emittance to about 5 nm rad at 2.75 GeV. At the end of the ramp an emittance exchange is foreseen to allow for more flexibility in the injection parameters into the storage ring. In order for a good efficiency of the emittance exchange, the coupling of the lattice has to be well controlled. This is achieved with a LOCO routine for coupling using 10 skew quadrupoles, but the so-called random tracking errors from the ramping magnet power supplies introduce noise in the response matrix measurement.Furthermore, an online measurement setup for the beam sizes using visible light and a slit mirror needs a careful beam position evaluation, which may be affected by tracking errors. For both these items, this contribution outlines the efforts and results achieved.
Paper: WEPM039
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM039
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
WEPM040
Improving the beam extraction efficiency from SPS to the North Area at CERN using octupole phase space folding technique
2015
The High Intensity ECN3 (HI-ECN3) project aims to increase the number of protons per pulse delivered to a new experimental facility in CERN’s North Area up to $\sim 4 \cdot 10^{19}$ per year. Such an upgrade requires the reduction of the beam loss at SPS electrostatic septum (ZS) by at least a factor of four, since the activation of this device is the main factor constraining transition to the higher beam intensity. In this work we demonstrate one of the possible solutions to this problem that relies on octupole assisted folding of the beam in phase space. Implementation of this technique allowed to significantly reduce the losses at the ZS whilst transferring the beam through the LSS2 line, which connects the SPS and the transfer lines in the North Area, without deteriorating the transmission.
Paper: WEPM040
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM040
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
WEPM043
Impact of non-linearities on collimation losses at the CERN Large Hadron Collider
2022
Since the start of the third operational run of the CERN Large Hadron Collider (LHC) in 2022, multiple observations have highlighted the significant influence of non-linearities within the accelerator on the collimation loss patterns of circulating beams. Understanding this phenomenon is particularly relevant for qualifying and validating collimation performance for machine operation at high intensity. In this study, we explore the capability of advanced numerical simulations to reproduce the observed loss patterns, incorporating a detailed representation of various nonlinearities. These include strong octupole fields and high chromaticity. An in-depth analysis comparing the simulation results to experimental measurements was conducted. These findings provide valuable insights into the interplay between machine non-linearities and beam losses.
Paper: WEPM043
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM043
About: Received: 28 May 2025 — Revised: 30 May 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
WEPM046
Optimising multi-turn extraction at CERN using transverse feedback
2034
Initial experimental investigations of transverse beam splitting, carried out at the CERN Proton Synchrotron, have demonstrated that transverse feedback is highly effective in controlling the characteristics of the transversally split beam. The feedback notably improves the intensity distribution among the beamlets and the emittance of the core, which is the portion of the beam remaining near its centre after the resonance-crossing process. The transverse feedback is set in resonance with the horizontal betatron tune while the tune crosses the fourth-order resonance, creating a double-resonance condition. A simple Hamiltonian model has been employed to explore the underlying double-resonance mechanism. This paper thoroughly examines detailed numerical simulations based on a realistic lattice model alongside beam measurements, to identify optimisation strategies for the use of transverse feedback in controlling the properties of split beams.
Paper: WEPM046
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM046
About: Received: 02 Jun 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
WEPM052
Observation of transverse resonance island buckets at the ESRF EBS
2046
The presence of third order horizontal resonance island buckets at the ESRF EBS has been observed in simulations and in the machine. The islands appear at a few mm distance from the core with a specific horizontal tune and octupole setting. When the electrons are kicked with an injection kicker, a fraction of the beam can be captured in the island. The procedures to send the beam into the island and to measure the capture rate and the lifetime of the beam in the island are described. The dependency of the presence of stable islands with different horizontal and vertical tunes and different octupole settings are shown.
Paper: WEPM052
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM052
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
WEPM054
Beam loss simulations for space charge mitigation in J-PARC MR
2054
The main ring synchrotron (MR) of the Japan Proton Accelerator Research Complex (J-PARC) provides high power proton beams to neutrino and hadron experiments. Since we are planning to increase the beam intensity from current $2.3 \times 10^{14}~$protons per pulse (ppp) to $3.3 \times 10^{14}~$ppp, we need to reduce the beam loss. In the J-PARC MR, the space charge is one of the main causes of beam loss. As a first step, we developed a new beam optics suppressing the space-charge-induced resonance which is the primary cause of the beam loss. In this paper, we report details of the beam loss mechanism in J-PARC MR by comparing the tune scan results of the present and new beam optics.
Paper: WEPM054
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM054
About: Received: 31 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
WEPM061
Dynamic aperture models for a time-varying high luminosity LHC lattice
2062
The evaluation of dynamic aperture (DA) under time-dependent variations of lattice parameters is essential for understanding the long-term stability of particle motion in the Large Hadron Collider (LHC) and enhancing the future performance of the High-Luminosity LHC (HL-LHC). In this work, we develop DA models that address the complexities introduced by time-varying effects, with a focus on the operational challenges posed by luminosity levelling. Building on established DA scaling laws, we aim at capturing the impact of evolving machine conditions during levelling. An initial simulation study is presented that compares the effects on DA of different levelling schemes that are expected to be routinely used during the HL-LHC operation, providing key insight into extending current DA models to accommodate time-dependent perturbations.
Paper: WEPM061
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM061
About: Received: 28 May 2025 — Revised: 30 May 2025 — Accepted: 01 Jun 2025 — Issue date: 06 Jun 2025
WEPM062
Advances in machine learning inference of dynamic aperture evaluation for the LHC
2066
Dynamic aperture (DA) is a crucial metric for understanding nonlinear beam dynamics and particle stability in circular accelerators like the Large Hadron Collider (LHC) and its future High-Luminosity LHC (HL-LHC) upgrade. Traditional methods for DA evaluation are computationally intensive, requiring extensive tracking of large particle ensembles over many turns. Recent advances in machine learning (ML) have shown that models, particularly architectures like Bidirectional Encoder Representations from Transformers (BERT), can significantly accelerate DA predictions while achieving accuracies comparable to traditional simulations. Enhanced uncertainty quantification techniques further improve model reliability, providing a foundation for robust active learning frameworks. This work presents the latest progress in DA inference, focusing on architectural advances, data preparation, and optimised training techniques. Applied to LHC tracking data, these improvements highlight the importance of high-quality data generation and customised training strategies for enhancing model performance and uncertainty management, paving the way for future HL-LHC studies.
Paper: WEPM062
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM062
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
WEPM067
Introducing an open-source 3D time-domain electromagnetic wakefield solver for beam-coupling impedance simulations
2074
The determination of electromagnetic wakefields and their impact on accelerator performance is a longstanding challenge in accelerator physics. These wakefields, induced by the interaction between a charged particle beam and the surrounding vacuum chamber structures, significantly affect beam stability and power dissipation. Accurate characterization of these effects via beam-coupling impedance is crucial for predicting and mitigating performance limitations. While analytical methods are sufficient for simple geometries, realistic accelerator components require full-wave, three-dimensional numerical solutions of Maxwell's equations. In alignment with CERN's Open Science initiative, this contribution introduces an open-source 3D electromagnetic time-domain solver specifically designed for computing wake potentials and impedances in arbitrary geometries. The solver’s numerical implementation, optimized for CUDA-enabled GPUs, is presented and validated through benchmarks against established commercial codes. By fostering a collaborative framework, this solver aspires to address emerging challenges in accelerator design.
Paper: WEPM067
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM067
About: Received: 27 May 2025 — Revised: 30 May 2025 — Accepted: 01 Jun 2025 — Issue date: 06 Jun 2025
WEPM068
Broadband characterization of the CERN-SPS driving and detuning impedance
2078
The CERN-SPS transverse impedance model plays an important role in predicting beam stability and guiding machine operation. This work advances the benchmarking of the SPS vertical impedance model through experimental investigations of mode-zero instability growth rates and intensity-dependent tune shifts as a function of chromaticity. Building on insights from previous measurement campaigns, this study aims to address persistent discrepancies in the high-frequency domain associated with the real driving component of the effective impedance. The 2024 campaign incorporates growth rate measurements at varied transverse tunes to eliminate potential resonance crossing effects that could artificially enhance the high-frequency mismatch. The imaginary component of the transverse impedance is likewise explored by correlating intensity-dependent tune shifts with chromaticity variations. By combining all measurements and beam dynamics simulation results, the driving and detuning impedance model of key elements will be refined, offering improved predictive capabilities for the current SPS transverse impedance model.
Paper: WEPM068
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM068
About: Received: 27 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
WEPM072
Computational analysis of shielding on the coherent synchrotron radiation generated by a 3D bunch
2086
The analysis and mitigation of collective beam effects, such as coherent synchrotron radiation (CSR), is a significant challenge in the generation of high-brightness beams. To this end, considerable effort has been invested in the development of simulation tools to accurately characterize the CSR generated by a bunch following a curved trajectory. In particular, with codes like LW3D and CoSyR, it is possible to model the CSR wake due to an evolving 3D bunch distribution in free space with minimal approximation. Recently, we have developed a simulation tool that self-consistently characterizes CSR through direct computation of the Liénard–Wiechert fields while accounting for the presence of shielding walls. In this work, we use this method to study the CSR shielding effect on a complex bunch moving through both a single dipole and a bunch compressor, with particular emphasis on the boundaries of validity of 1D theory in predicting the phase space evolution. This work is part of a broad effort to investigate the impact of shielding both theoretically and through a series of planned experiments at the Argonne Wakefield Accelerator (AWA).
Paper: WEPM072
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM072
About: Received: 29 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
WEPM075
Beam impedance investigation of the elliptical interconnecting vacuum modules of the LHC and prospect for HL-LHC
2098
In view of ensuring the successful completion of the third operational run of the Large Hadron Collider (LHC) and preparing for the High-Luminosity LHC era, a systematic assessment of the risk of failure of all the vacuum interconnection modules installed in the accelerator is being carried out. This was prompted by a significant pressure rise in 2023, localized near an interconnection module (212 mm inner diameter) caused by a localized impedance-induced heating on the tension spring. This led to degradation and loss of electrical contact of the Radiofrequency (RF) sliding fingers. The studies include the evaluation of the various modules currently present in the LHC, alongside the description of a mitigation strategy. In this paper, we focus on the study of elliptical vacuum modules both from the point of view of electromagnetic simulations and of experimental validation. We report also on the general strategy where the most critical vacuum modules with sliding contact RF fingers, featuring tension springs, will be replaced with upgraded designs to avoid issues and therefore ensure improved reliability under future operational conditions with higher bunch intensities.
Paper: WEPM075
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM075
About: Received: 27 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
WEPM076
Beam coupling impedance wireless measurements and application to HL-LHC accelerator components
2102
A novel wireless method for beam coupling impedance measurements is currently under development, with preliminary measurements on beam pipes serving as proof of concept for its validity. This innovative approach overcomes the limitations of existing methods by not only evaluating impedance with high accuracy but also enabling the characterization of an unknown Device Under Test (DUT) as it will be installed in the accelerator. This capability is crucial for constructing accurate impedance models of accelerators and may help resolve or reduce discrepancies between modelled and measured impedance contributions. While analytical computations or simulations can provide accurate predictions of the beam coupling impedance for simple beam pipes with well-defined material properties, they often fail to account for real-world imperfections, such as surface roughness. Potential applications of this method are the characterization of High-Luminosity LHC collimators and other beam vacuum components planned for future installation. By providing detailed insights into their impedance contribution, this method could play a pivotal role in achieving a highly accurate HL-LHC impedance model.
Paper: WEPM076
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM076
About: Received: 27 May 2025 — Revised: 01 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
WEPM078
Impedance benchmarking of resistive wall and tapered transitions for the PF-HLS
2110
The PF Hybrid Light Source (PF-HLS) has been proposed in the High Energy Accelerator Research Organization (KEK), capable of utilizing both high-quality beams from a superconducting linac and beams from a low-emittance storage ring. The coupling impedance will cause beam instability, which must be carefully handled. It is essential to benchmark impedance models using analytical methods and different simulation codes. This paper focuses on the impedance benchmarking of resistive wall and tapered transitions in PF-HLS. The regular round chamber (radius of 12 mm), insertion device (ID) chamber (half-height of 4 mm), and the corresponding tapered transitions are studied. Simulation codes, including ImpedanceWake2D (IW2D), CST, and Azimuthal Beam Cavity Interaction (ABCI), are used. For resistive wall calculations, some analytical formulae describing the round chamber impedance and the Yokoya form factors of the ID chamber are applied. For tapered transitions, some formulae calculating the impedance at low-frequency regions (inductive regime) are chosen to compare with results from CST. In high-frequency regions, the impedance result comparison between CST and ABCI is carried out.
Paper: WEPM078
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM078
About: Received: 21 May 2025 — Revised: 29 May 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
WEPM080
Impact of the cSTART impedance on beam dynamics
2117
The combination of a compact storage ring and a laser-plasma accelerator (LPA) can serve as the basis for future compact light sources. One challenge is the large momentum spread (about 2%) of the electron beams delivered by the LPA. To overcome this challenge, a very large acceptance compact storage ring (VLA-cSR) was designed as part of the compact STorage ring for Accelerator Research and Technology (cSTART) project, which will be realized at the Karlsruhe Institute of Technology (KIT, Germany). Initially, the Ferninfrarot Linac- Und Test-Experiment (FLUTE), a versatile source of ultra-short bunches, will serve as an injector for the VLA-cSR to benchmark and emulate LPA-like beams. In a second stage, a laser-plasma accelerator will be used as an injector. The large-momentum spread bunches in non-equilibrium and with charges from 1 pC to 1 nC and lengths from few fs to few ps pose challenges for the beam dynamics simulations. An understanding of the ultra-short bunch dynamics also requires an impedance model up to high frequencies. Here, we present first results on the impact of the machine impedance to the beam dynamics.
Paper: WEPM080
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM080
About: Received: 26 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
WEPM081
Numerical modeling of the CERN PS booster cavity feedback loops
2121
The Radio-Frequency (RF) system of the CERN Proton Synchrotron Booster (PSB) features Finemet-loaded cavities that cover a wide range of frequencies. This system generates a significant broad-band longitudinal impedance, which must be mitigated to maintain beam stability, particularly at higher beam intensities. To counteract the induced voltage, a direct RF feedback is employed over the entire operational frequency range. It is complemented by a multi-harmonic feedback that applies narrow-band signal processing to reduce the cavity impedance at integer multiples of the revolution frequency. Recent measurements have revealed that these long-delay cavity loops implemented in the Low-Level RF (LLRF) system have a substantial effect on beam dynamics. To validate the impedance model in the closed-loop regime, a detailed model of their behaviour is necessary. This contribution outlines the development process of the numerical model for the PSB cavity feedback loops for particle tracking simulations, which is based on dedicated measurements used to characterise the feedback performance. Comparisons between simulations and measurements are carried-out to assess the validity of the modeling.
Paper: WEPM081
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM081
About: Received: 27 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
WEPM091
Estimation of the microwave instability at ALBA
2144
In a collaborative work between ALBA and KEK the computation of the microwave instability threshold of the current ALBA ring was initiated. This analysis involves solving the dispersion relation equation* and conducting simulations using a Vlasov-Fokker-Planck (VFP) solver**. The longitudinal wake fields of geometric origin of all vacuum elements were computed with GdfidL*** using a bunch whose length is at least 5x smaller than the bunch length given by usual 3MV RF-voltage applied at ALBA. The resistive wall contribution was computed at first as longitudinal impedance by IW2D**** to be converted in a second step into wake fields via Fourier transform. The CSR contribution will also be considered. The impact of the 3 types of wakes on the microwave instability will be studied. The microwave instability single bunch threshold will be computed combining the 3 contributions. This work also serves as a preparation of the future evaluation of the microwave instability of the ALBA upgrade, which is expected for 2030.
Paper: WEPM091
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM091
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
WEPM092
Investigating ion beam loss mechanisms at the SPS flat bottom
2148
The long injection segment (flat bottom) of the cycle in the Super Proton Synchrotron (SPS) used for filling the Large Hadron Collider (LHC) with Pb ion beams, exhibits strong beam losses and transverse emittance growth. During the 2024 run, large improvements of the beam transmission could be made such that record intensities could be delivered to the LHC. In particular, these improvements were enabled by operational measures such as working point optimization and a numerical compensation scheme for the 50 Hz ripple from the main quadrupole power converters. This paper provides a summary of these improvements, and presents recent advancements in particle tracking simulations of the SPS flat bottom, including effects such as intra-beam scattering and space charge in the presence of tune modulation induced by power converter noise. These simulations are compared with transverse and longitudinal beam measurements. The relative importance of each effect and their estimated impact on the future ion programmes at CERN are discussed.
Paper: WEPM092
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM092
About: Received: 27 May 2025 — Revised: 03 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
WEPM093
A particle-in-cell implementation of intra-beam scattering for Xsuite
2152
Intra-Beam Scattering (IBS) remains one of the primary mechanisms of emittance blow-up and performance degradation in the Large Hadron Collider (LHC) accelerator chain. The phenomenon is particularly relevant following the recent injector upgrades to achieve the high-brightness beams required for the High Luminosity LHC (HL-LHC) era. Traditional IBS models, as those already implemented in Xsuite, rely on the assumption of Gaussian beam distributions. However, observations in the CERN complex indicate the presence of q-Gaussian beam profiles, for which these models do not accurately reproduce IBS effects. To address this limitation, a Particle-In-Cell (PIC) approach was developed that operates independently of distribution assumptions. This methodology behind the PIC approach, and benchmarks against existing models as well as experimental data from the LHC are presented in this contribution. Current limitations are also discussed.
Paper: WEPM093
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM093
About: Received: 22 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
WEPM095
Transverse coherent direct space charge: comparison between several approaches
2160
The proton driver of a future Muon Collider complex is designed to deliver a multi-GeV, short and high-intensity proton bunch to a target in order to maximize the muon yield. In the International Muon Collider Collaboration (IMCC), two high power H- Linac configurations are studied: a 2 MW with a beam energy of 5 GeV, and a 4 MW with a beam energy of 10 GeV. The Linac is followed by an accumulator ring and a compressor ring. With a single bunch intensity of 5.0e14 protons within a transverse emittance of ~15 mm mrad, strong space-charge effects can be expected in these rings. In this framework, different simulation codes used to estimate the transverse coherent space-charge mode frequency shifts in synchrotrons have been compared: BimBim, based on the Circulant Matrix Model (CMM); the Effective impedance method for space-charge; GALACTIC based on the Vlasov equation; the boxcar model for space-charge only; and the ABS model which assumes an Air-Bag bunch distribution in a Square well.
Paper: WEPM095
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM095
About: Received: 29 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
WEPM099
Investigation of the microwave instability at MAX IV laboratory in combination with intra-beam scattering
2168
With the increasingly challenging parameters in 4th generation synchrotron light sources, collective effects causing instabilities are putting even stronger limitations on the area of stable operation. The microwave instability (MWI) is a longitudinal single-bunch instability driven by the geometric and the resistive-wall impedances. While the instability typically does not result in a beam loss, the resulting turbulent dynamics are accompanied by an increased energy spread and therefore deteriorate the light source performance. The threshold current depends on different beam parameters and can, without mitigation, for recently upgraded or currently under design light sources, be as low as or lower than the intended design current per bunch. At the same time, the instability threshold is also influenced by other collective effects such as the intra-beam scattering (IBS). The influence of the IBS on the microwave instability has been studied for the 3 GeV storage ring at the MAX IV laboratory. The presented experimental results show the expected influence on the MWI threshold by the coupling strength due to the resulting changes in the IBS.
Paper: WEPM099
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM099
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
WEPM103
Studies on the large residual horizontal orbit in the SIRIUS booster
2176
SIRIUS, the Brazilian 4th-generation synchrotron light source, operates in top-up mode at a current of 200 mA. Despite previous optimizations, the storage ring injection system still requires improvements in efficiency, to attend the tight demands in terms of repeatability and charge per pulse. In this context, this work investigates the large residual horizontal orbit distortion in the booster, that cannot be corrected with the current orbit correction system. A method to mitigate the problem, based on displacing focusing quadrupoles horizontally will be analyzed. Additionally, a hypothesis to explain the origin of the distortion, based on dipole error correlations introduced by the magnet sorting algorithm, will be investigated.
Paper: WEPM103
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM103
About: Received: 28 May 2025 — Revised: 01 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
WEPM112
Characterization of beam optics considering fringe fields of quadrupole magnets in a LIPAc 5 MeV beamline
2194
The 5 MeV beamline of Phase B+ which is an intermediate commissioning stage of the Linear IFMIF Prototype Accelerator (LIPAc) consists of an MEBT, an MEBT Extension Line (MEL) where the SRF will be installed, a HEBT, and a beam dump. It has 17 quadrupole magnets, and some quads have small aperture-to-length ratios and are also densely installed in the MEBT and HEBT sections. In the early stages of Phase B+, we optimized the beam optics with the conventional hard-edge model for all the quads. However, we observed unwanted particle losses and discrepancies in the rms beam sizes between measurements and simulations due to significant fringe fields and magnetic interference. After considering the field maps and the magnetic interference of the quads in the beam optics, we could obtain the matching beam and reduce the particle losses. In this paper, we characterize the beam optics by comparing the transfer matrices with and without the fringe fields and the interferences using a conventional hard-edge model and a more accurate hard-edge model equivalent to the field maps.
Paper: WEPM112
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM112
About: Received: 16 May 2025 — Revised: 01 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
WEPS008
Longitudinal microwave instability in the J-PARC Main Ring
2213
Longitudinal microwave instability has been observed in the J-PARC Main Ring. The longitudinal microwave instability was observed during the debunching process for the slow extraction. This led to electron cloud formation, which can cause transverse beam instability and beam losses. Longitudinal microwave instability was also observed during the latter part of the acceleration for the fast extraction operation, even though no loss or transverse instability related to the longitudinal microwave instability was observed. To investigate the source of the longitudinal microwave instability, spectral analysis was used on the waveform recorded by a high-speed oscilloscope. The spectral analysis suggests the RF cavity and its structure as a possible source of the longitudinal microwave instability. A beam longitudinal dynamics simulation with measured longitudinal impedance of the RF cavity was performed, and its result is compared with the measurement for various beam intensities. In this paper, we present the result of the simulation and measurement of the longitudinal microwave instabilities for various beam intensities.
Paper: WEPS008
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS008
About: Received: 28 May 2025 — Revised: 31 May 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
WEPS011
Machine learning-based symplectic model for space-charge effect simulation
2225
Symplectic simulation of space-charge effects is important for high-intensity particle accelerators. In this work, we propose to use a generative model to efficiently simulate space-charge effects in JuTrack, a Julia-based particle tracking code. The one-step symplectic transverse transfer map of the particles is obtained by differentiating the predicted space-charge Hamiltonian. This model effectively preserves the phase-space structure and reduces non-physical effects in long-term simulations by ensuring symplecticity in the calculation.
Paper: WEPS011
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS011
About: Received: 16 May 2025 — Revised: 01 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
WEPS012
Beam loss simulations with space charge and octupoles for the SIS100 magnet quality assessment
2228
The components of the SIS100 synchrotron (FAIR facility) are presently under installation in the accelerator tunnel. The superconducting dipole magnets have been produced and the magnet field errors up to 7th order have been measured for all magnets. The superconducting quadrupole magnets are under production, the field error data for a part of the magnets is available. As a part of the magnet quality assessment, the particle tracking simulations are used to study the beam losses during the 1 sec beam accumulation at the injection energy. The tune settings for the slow extraction operation are considered. Direct space-charge effects and the Landau damping octupole magnets, which dominate the incoherent tune distribution, are included. In order to reduce the computational load and to increase the parameter resolution, a machine learning based optimizer is used in the accelerator and beam parameter studies.
Paper: WEPS012
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS012
About: Received: 23 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
WEPS015
Simulation of electron beam transport through the coherent electron cooling amplification section using real number of electrons
2232
Coherent electron cooling plays an important role in the Electron Ion Collider (EIC) by providing a fast cooling rate at collision energy to counter the emittance growth driven by intrabeam scattering effects. In this paper, we report on the high-fidelity simulation of the electron beam transport through the amplification section of the cooling channel. We will show the amplification of the initial modulation in the electron beam from the protons and present the study of collective effects such as the space-charge and CSR effects on the process of modulation amplification.
Paper: WEPS015
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS015
About: Received: 20 May 2025 — Revised: 31 May 2025 — Accepted: 31 May 2025 — Issue date: 06 Jun 2025
WEPS018
Bunch length regulation in the LHC during controlled emittance blow-up
2240
Controlled longitudinal emittance blow-up is indispensable for the operation of the Large Hadron Collider (LHC) to counteract single-bunch loss of Landau damping during the acceleration ramp. The blow-up is performed by injecting RF phase noise in a narrow frequency band into the beam phase loop, with bunch-length feedback regulating the noise amplitude. In 2024, the variation of the bunch length due to imperfect regulation caused unacceptable beam-induced heating of certain accelerator components. In this contribution, we present the results of extensive simulation scans that have been used to optimize the feedback parameters. We show how this optimization, along with a reduction of the feedback delay on the controls side, has been implemented in the LHC and significantly improved the bunch length evolution during acceleration. Finally, we discuss the results of a measurement scan performed during an operational period of five weeks to fine-tune the blow-up feedback settings.
Paper: WEPS018
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS018
About: Received: 26 May 2025 — Revised: 30 May 2025 — Accepted: 01 Jun 2025 — Issue date: 06 Jun 2025
WEPS020
Preliminary study of higher-order mode based scheme for bunch length compression in SRF Electron guns
2244
Higher-Order Modes (HOMs) in superconducting radiofrequency (SRF) cavities are traditionally considered detrimental to efficient operation. They are often associated with beam instabilities and are actively damped. However, these “harmful” HOMs, if used strategically, can be transformed into a tool for providing extra control over the beam, which can introduce new opportunities that are not easily achievable by conventional SRF cavity-based systems. Particularly, we have investigated the feasibility of boosting ballistic bunch compression using HOMs in SRF gun. The proposed idea will be presented with preliminary simulation results. The 185 MHz SRF gun cavity used for the simulation study was modelled using the ACE3P software suite and further modelling of the compression scheme was performed using the GPT code.
Paper: WEPS020
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS020
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
WEPS021
Simulation study on attosecond bunch generation using reversed chicane at Argonne Wakefield Accelerator (AWA)
2247
Capability for generating an attosecond bunch can provide interesting opportunities to wakefield accelerator research. We have been studying requirements and challenges in beam dynamics to produce an attosecond bunch using an existing beamline at Argonne Wakefield Accelerator (AWA) facility. One unavoidable limitation of this study is that conventional C-typed chicane is not available. Thus, a modified version of a chicane-like compressor, called a reversed chicane, is designed and running at the AWA facility. AWA’s injector and beamline were simulated using ASTRA and ELEGANT respectively. The study provided guidance toward the attosecond bunch generation. We present the simulation results and propose the modified design and operation conditions to generate the attosecond bunch at AWA facility.
Paper: WEPS021
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS021
About: Received: 28 May 2025 — Revised: 31 May 2025 — Accepted: 31 May 2025 — Issue date: 06 Jun 2025
WEPS025
Design, manufacturing and validation of fast-ramping alpha magnet for interleaving operation at ANL APS
2259
RadiaBeam has designed and manufactured a fast-ramping alpha magnet (FRAM) that is developed for interleaved operation at the Advanced Photon Source (APS) at Argonne National Laboratory. This interleaving operation requires the alpha magnet to stably complete a 5 s long cycle with a 100 ms ramp-up, 1s nominal field output and a 100 ms ramp-down. A laminated yoke is used to minimize eddy currents, ensure fast field response times and reduce core-loss during operation. The magnet has been measured by a Hall probe at Radiabeam and at Argonne, demonstrating 2.75 T/m maximum field gradi-ent within a 10 cm x 14 cm good field region in both DC and pulse modes.
Paper: WEPS025
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS025
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
WEPS028
Quadrupole pumping for bunch shortening in the Proton Synchrotron and Super Proton Synchrotron at CERN
2263
Quadrupole pumping is a longitudinal manipulation technique for bunch shortening, which works by modulating the RF voltage at twice the synchrotron frequency to excite bunch length oscillations. These controlled oscillations rotate the bunch in longitudinal phase space, with extraction set for when the bunch is shortest. Higher RF harmonics can also be used to linearise the synchrotron frequency distribution, reducing the formation of tails. Recently, quadrupole pumping has been proposed as a method for achieving ultra short bunches for proton-driven plasma wakefield accelerators such as the AWAKE experiment. In this contribution, we assess the performance of quadrupole pumping for the first time in the Proton Synchrotron (PS) and Super Proton Synchrotron (SPS) at CERN. Using simulations and beam measurements, we compare the effectiveness of this technique (without linearisation) against other bunch-shortening methods, including the unstable phase jump and the non-adiabatic voltage jump.
Paper: WEPS028
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS028
About: Received: 27 May 2025 — Revised: 03 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
WEPS029
Predicting losses in the SPS using longitudinal tomography during bunch shortening in the PS
2267
The efficient transfer of protons from the Proton Synchrotron (PS) to the Super Proton Synchrotron (SPS) is crucial for beams in the Large Hadron Collider (LHC). A particular challenge at the intensities required for the High-Luminosity LHC is the handover from a 40 MHz to a 200 MHz RF system. This requires a non-adiabatic bunch shortening in the PS triggered by a fast RF voltage jump. However, nonlinearity of the synchrotron frequency distribution causes tails to emerge during rotation, resulting in uncaptured beam in the SPS. The uncaptured particles lost at the start of acceleration in the SPS, and the additional flat bottom losses, can currently only be evaluated with the beam intensity and loss monitors. In this work, detailed studies of the bunch rotation in the PS were carried out both in simulations and in measurements. A tomography-based tool was developed to predict uncaptured losses in the SPS from bunch profile measurements in the PS during bunch shortening. This tool enables detailed monitoring of the PS-to-SPS transfer of LHC-type beams by identifying potential losses due to uncaptured beam, before injection into the SPS.
Paper: WEPS029
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS029
About: Received: 27 May 2025 — Revised: 01 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
WEPS035
Characterizing proton beam properties for cell irradiation study using GEANT4 simulation
2275
The purpose of this research is to characterize proton beam properties - beam energy, energy spread, beam size, and transverse emittance - to establish the initial setup for simulation in planning cancer cell culture experiments at the Cyclotron Medical Accelerator at King Chulalongkorn Memorial Hospital in Bangkok, Thailand. The characterization was performed using GEANT4 Monte Carlo (MC) simulations. Proton energies of 70 MeV, 100 MeV, 150 MeV, and 220 MeV were selected, and the 80%-20% distal fall-off of the depth profile was utilized to determine the energy spread. The simulated results were then verified against experimental data and compared with the Treatment Planning System (TPS). The details of the validating procedure, as well as results on the optimized energy spread, beam size, and emittance, and the irradiated setup for cell irradiation, will be discussed in this contribution.
Paper: WEPS035
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS035
About: Received: 26 May 2025 — Revised: 30 May 2025 — Accepted: 30 May 2025 — Issue date: 06 Jun 2025
WEPS036
First proton crabbing at the LHC via head-on beam-beam interaction
2278
The first experimental observation of a 10 $\mu$m crabbing orbit at 1~$\sigma_z$ induced by head-on collisions with a non-zero crossing angle ($\theta_c$) in a high-energy proton beam at the LHC is presented. This challenging measurement required both the design of a dedicated experiment and a careful calibration and optimization of the beam instrumentation to produce and detect such a subtle effect. By varying the crossing angle from positive to negative values the reversibility of the effect and its dependence on the crossing angle were also demonstrated. Lattice simulations were performed to corroborate the experimental results, showing excellent agreement with the measured crabbing amplitudes. This experiment highlights the potential of the existing wideband beam-position monitors to diagnose crabbing effects, which will be crucial in the HL-LHC upgrade.
Paper: WEPS036
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS036
About: Received: 19 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
WEPS038
Python FLUKA beam line, a python library to create FLUKA simulations of accelerators
2282
FLUKA simulations of beamlines are important for un- derstanding numerous different aspects of accelerators, in- cluding beam losses, particle backgrounds, activation and shielding. Creating a beam-line simulation using FLUKA is a time consuming and potentially error prone process. This paper describes a set of python tools called pyflubl (Python FLUKA beam-line) which can create a FLUKA simulation using input from MAD-X, MAD8, Transport or BDSIM. pyflubl is based on multiple stable and advanced python packages created to make BDSIM (Geant4) beamline simu- lations as simple as possible, these are pymadx (an interface to MAD-X output), pymad8 (an interface to MAD8 out- put), pybdsim (interface to BDSIM) and most importantly pyg4ometry (a geometry engine for Monte Carlo geometry creation). The magnetic fields required for FLUKA are im- plemented in C++ via BDSIM, thus keeping fields consistent between Geant4 and FLUKA beamline simulations. This paper describes pyflubl design and implementation and ex- ample results for an idealised electron beam-line. Particular attention is given to geometry, fields and scoring.
Paper: WEPS038
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS038
About: Received: 28 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
WEPS039
Progress & developments of beam delivery simulation (BDSIM)
2286
BDSIM (Beam Delivery Simulation) is a Monte Carlo particle tracking tool for accelerator beamline modelling. It integrates particle transport with detailed geometry and physics using Geant4 for precise modelling of particle-matter interactions in 3D models of particle accelerators. Primarily for energy deposition studies and beam loss simulations, BDSIM allows a high degree of control and customisation, and is ideal for understanding and enhancing the performance of beamline designs. BDSIM has numerous modelling applications, including high-energy physics facilities, particle detection experiments, synchrotron light sources, medical accelerators, and novel acceleration experiments. Here, we present recent developments of BDSIM. This includes improved custom inverse-Compton scattering processes for laserwire and polarimeter simulations and extending the process to model polarization & electron spin; improved acceleration including transverse focussing in RF elements with implementation of 3D transverse magnetic and electric modes; custom elements for modelling muon cooling channels; and updates to interfacing with Xsuite via improved code couplings and BDSIM distribution methods.
Paper: WEPS039
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS039
About: Received: 28 May 2025 — Revised: 01 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
WEPS042
Benchmarking Intrabeam Scattering with RF-Track
2294
Intra-beam scattering (IBS) has recently gained significant interest in the community of free electron lasers (FELs), as it is believed to produce an increment in the sliced energy spread (SES), which is detrimental to FEL performance. To control and contain this phenomenon, it is important to include IBS in the design phase of an FEL through appropriate numerical simulation. Most existing codes that simulate IBS were developed for long-term tracking in circular lattices, assuming Gaussian bunches. Unfortunately, this assumption doesn’t capture the rapid bunch evolution of electron bunches in photoinjectors. To address this limitation, the tracking code RF-Track has recently been updated to include IBS, using a novel hybrid-kinetic Monte Carlo method. This paper presents benchmarks performed to verify the implementation. The predicted SES increment in the beam due to IBS using RF-Track has been compared against a kinetic approach used in a different tracking code and, secondly, against a semi-analytical model. The results showed a good agreement, setting RF-Track as a tool to understand and control the SES growth in photoinjectors and, in particular, in FEL.
Paper: WEPS042
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS042
About: Received: 04 Apr 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
WEPS043
Achieving diverse beam modes with modelling and optimisation for the versatile SRF photoelectron gun at SEALab
2298
The SEALab facility in Berlin is home to an R\&D superconducting radio-frequency (SRF)photoinjector setup and beamline. Designed to support multiple varied applications - ranging from Energy Recovery Linac (ERL) to Ultrafast Electron Diffraction (UED) and Electron-Beam Water Treatment (EBWT) - SEALab requires flexible, high-precision tuning to support these diverse beam modes. These applications span over three orders of magnitude in bunch charge, emittance, and current, alongside sub-picosecond pulse lengths. This makes injector setup and tuning a significant challenge. With the world's first beam achieved at SEALab from a Na-K-Sb cathode in our SRF gun, a suite of beam dynamics models has been developed to support understanding of the beam behaviours in the gun, where no observations are possible, and operation of the commissioning process. This is comprised of a first-order analytical model, particle-in-cell (PIC) ASTRA simulations, and a machine-learning surrogate model trained for current commissioning operation ranges. These models are coupled with a Multi-Objective Bayesian Optimisation (MOBO) algorithm to enable rapid tuning across multiple beam modes. This combination of surrogate modelling and optimisation algorithm reduces optimisation timescales from hundreds of hours to minutes, allowing near-real-time tuning for the accelerator. This work presents the modelling framework, its validation, and its application to SEALab's many-mode optimisation challenges.
Paper: WEPS043
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS043
About: Received: 28 May 2025 — Revised: 01 Jun 2025 — Accepted: 01 Jun 2025 — Issue date: 06 Jun 2025
WEPS045
Investigating the Impact of alternative LHC optics on accelerator backgrounds at FASER using BDSIM
2302
Alternative configurations around the ATLAS experiment are investigated aiming to reduce muon rates at forward physics experiments such as FASER and SND@LHC. The Geant4 toolkit BDSIM is used to propagate muons through a model of a section of the LHC and the TI12 tunnel, where the FASER experiment is located. We compare the muon rates in BDSIM with FASER data collected during dedicated tests in the LHC. Results show a significant worsening of the background with the non-nominal polarity configuration of the triplet quadrupoles, used in 2024. The horizontal crossing angle further increased the background, however a partial mitigation of approximately 10% was found using a set of orbit corrector magnets. Additionally, nominal triplet polarity was favorable for both vertical and horizontal crossing angles. This work served as benchmark of simulations that will be used to validate future configurations.
Paper: WEPS045
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS045
About: Received: 28 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
WEPS047
Report on Opera-3D hands-on session in the 7th International School on Beam Dynamics and Accelerator Technology (ISBA24)
2306
The 7th International School on Beam Dynamics and Accelerator Technology (ISBA24) held in Chiangmai University during November 1-9, 2024, encompasses seven days opportunities where the foundation of accelerator physics is applied during hands-on sessions with simulation software including ASTRA, ELEGANT, Opera-3D and CST Studio Suite. Opera-3D, a finite element-based Maxwell’s equations solver, is known for its powerful low frequency simulation capabilities and is appropriate for magnet design. Instructed by two lecturers from Synchrotron Light Research Institute, 15 students from China, Japan, India and Thailand were trained on the Opera-3D software fundamentals in the application of magnet design for particle accelerator. The students showcase their knowledge in the group assignments including the design of H-shape dipole, C-shape dipole and combined horizontal and vertical corrector with success. Thanks to the generous support of the ISBA24 sponsors and Sigma Solutions Co., Ltd., who provided the software licenses during the school. This article reports on the completion of the ISBA24 Opera-3D hands-on session provided to graduate students and young researchers from the Asian region.
Paper: WEPS047
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS047
About: Received: 18 May 2025 — Revised: 30 May 2025 — Accepted: 31 May 2025 — Issue date: 06 Jun 2025
WEPS059
Simulation study on power loss in the coupling cavity damper of the accelerating π/2 mode for the SuperKEKB ARES cavity
2327
In the SuperKEKB electron-positron collider, the coupled-bunch instability caused by the accelerating mode of RF cavities becomes severe in high beam current. To suppress it, the ARES cavities have been used. The accelerating cavity is coupled with an energy storage cavity via a coupling cavity between them. While the beam is accelerated by the π/2 mode, the parasitic 0 and π modes are damped by a coaxial damper at the coupling cavity without damping the π/2 mode. However, as the beam current becomes higher, some of the accelerating field of the π/2 mode is absorbed by the damper. This is because the π/2-mode field is deformed when two frequency tuners in the accelerating and storage cavities are moved for the optimum tuning condition. This effect increases power load of the damper, which can be an issue at higher beam current. Our high-power test showed that the power loss was higher than a prediction of the equivalent circuit model. Thus, using the CST MW Studio, we simulated the power loss and studied the relation between the power loss and the detuning frequency. We compare the simulation and high-power test results and discuss the possibility of new frequency tuning schemes.
Paper: WEPS059
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS059
About: Received: 26 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
WEPS063
Estimation of coupled-bunch instability induced by high-order modes of bell-shaped cavity in high current operation at SPring-8-II
2334
At the large synchrotron radiation facility SPring-8, the upgrade project “SPring-8-II” is underway to increase the radiation brightness by 100 times. In SPring-8-II, the beam energy will be reduced from 8 GeV to 6 GeV and the beam current will increase from 100 mA to 200 mA. The bell-shaped 509 MHz cavities will remain in place at SPring-8-II, with the number of cavities reduced from 32 to 16. Currently, the longitudinal coupled-bunch instability (CBI) is not observed. However, the CBI may occur due to high-order modes (HOMs) in some cavities because of the parameter changing at SPring-8-II. We estimated the threshold shunt impedance and Q-value for the CBI by using Ansys HFSS. Especially, TM011 mode at 900 MHz has a large impedance and the threshold impedance is 0.8 MΩ, which corresponds to QL~12,000 when R/Q=65Ω. On the other hand, we measured the actual QL-value of the cavities using single-bunch beam. The spectra and its Q-values of the HOM induced by the beam were measured. The results show that most cavities are below the threshold, but some cavities are over threshold. If the HOM causes instability, we plan to adjust two tuner plungers to shift them off the peak.
Paper: WEPS063
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS063
About: Received: 30 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
WEPS065
Development of C-band compact accelerating structure made of longitudinally-split two halves
2338
Our 6 MeV medical C-band accelerating structure is assembled using the disk-stacked method, where multiple oxygen-free copper components are stacked along the beam axis. The design incorporates the side-coupled (SC) structure and the re-entrant structure with an accelerating gap at the center of the cavity. Due to the complex shape and the large nunber of components, there are challenges in manufacturing efficiency. On the other hand, the longitudinally-split method divides the structure along a plane passing through the beam axis, independent of the number of cells, which significantly reduces the number of components. Based on the longitudinally-split X-band accelerating structure developed in the CLIC project, we have been working on the development of a compact, high-gradient, high-shunt impedance, longitudinally-split SC-type C-band accelerating structure. In this presentation, we will report the progress of our work, including manufacturing, RF testing, frequency tuning, and beam testing in the actual operating conditions.
Paper: WEPS065
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS065
About: Received: 27 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
WEPS071
Microwave instability driven by terahertz-scale resistive-wall impedance in Diamond-II
2352
Vacuum vessels of the Diamond-II storage ring feature non-evaporable getter (NEG) coating which cause a resonator-like peak in the longitudinal impedance. This work demonstrates how different parameters of NEG can increase momentum-spread growth. It is shown that the spread of the coating-layer thickness amongst vacuum vessels results in significantly reduced momentum-spread growth. Insertion devices featuring rectangular geometry and NEG coating can cause a multi-peak structure of the longitudinal impedance which can drive additional momentum-spread growth.
Paper: WEPS071
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS071
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
WEPS076
Thresholds of longitudinal multi-bunch instabilities in double harmonic RF systems
2359
Multi-bunch instabilities, often driven by narrowband impedance sources such as higher-order modes, present significant intensity limitations in synchrotrons. One approach to mitigate these instabilities is applying a double harmonic radio frequency (RF) system, which can increase the intensity threshold by enlarging the synchrotron frequency spread. In this study, intensity thresholds are calculated for different RF parameters using stability diagrams derived from the Lebedev equation. We analysed configurations and beam characteristics relevant to the synchrotrons at CERN, particularly focusing on the Super Proton Synchrotron (SPS). The semi-analytical results were then compared to macroparticle simulations and measurements. The findings reveal an unexpected beam stabilisation even if a non-monotonic amplitude dependency of the synchrotron frequency is present. Further, techniques for deducing the driving impedance parameters are discussed.
Paper: WEPS076
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS076
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
WEPS090
Touschek effect in Super Charm Tau factory
2366
Super Charm Tau factory is a proposed electron-positron double ring collider with crab waist collision scheme operating in wide beam energy range from 1.5 GeV to 3.5 GeV with peak luminosity of 10^35 cm^(-2) s^(-1). The polarized electron source and three Siberian Snakes provide 80% longitudinally polarized electron beam at 2 GeV. Superconducting wigglers decrease damping times, effects of intra-beam scattering and increase Touschek beam lifetime, particularly at low energy. This work presents studies of the Touschek effect in SCTF, as well as the results of a simulation of Touschek scattering, MOGA optimization of local momentum acceptance, and an investigation into the dependence of the dynamic aperture and the Touschek lifetime on the average orbit error.
Paper: WEPS090
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS090
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
WEPS100
Impedance reduction of the beam wire scanners for the CERN LHC
2376
The beam wire scanners are instruments for precise transverse beam profile measurements by detecting the secondary particles generated from the interaction of the beam with a moving carbon wire. Following a completely new design of this device for the Large Hadron Collider (LHC), a detailed impedance calculation has been performed already in the design phase. This contribution presents the beam coupling impedance optimization and reduction strategy of the beam wire scanners for the High-Luminosity (HL) upgrade of the LHC. Prior to the construction of the prototype, extensive three-dimensional electromagnetic simulations of the proposed mechanical designs were performed to detect potential resonances and their sources. The mechanical model was improved to minimize the beam coupling impedance by geometrical modifications and coatings. We also present the beam-induced RF power loss calculation of the instrument.
Paper: WEPS100
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS100
About: Received: 28 May 2025 — Revised: 30 May 2025 — Accepted: 31 May 2025 — Issue date: 06 Jun 2025
WEPS135
RF window ghost mode analysis
2404
The RF window acts as a barrier between the vacuum and air, gas, or water while allowing RF power to pass through with minimal loss. Resonant modes (called "ghost modes") can occur within the ceramic disk of a window. The frequencies of these modes depend on the material and size of the ceramic. Ceramic disk dimensions must be carefully optimized to minimize reflections and avoid ghost mode resonances within the operating bandwidth. In this paper we present the design of an input window used in an X-band klystron. The dimensions of the window and ceramic disk are optimized to minimize insertion and reflection losses while preventing ghost mode resonances in the operating bandwidth. In addition to this, we ensure that the maximum electric field at the window surface is kept low to reduce the probability of RF breakdowns. Analytical analysis, numerical simulations and experimental measurements of the ghost modes of ceramic disks were carried out. The measured ghost mode frequency was used to evaluate the ceramic dielectric constant. In this article we present simulated and measured results.
Paper: WEPS135
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS135
About: Received: 29 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
WEPS143
Ongoing vertical testing and high-pressure rinsing simulations of single-spoke resonator cavities
2407
Vertical tests of single-spoke resonator type 1 (SSR1) superconducting cavities were conducted in conjunction with high-pressure rinsing (HPR) simulations to assess and improve cavity performance. The quality factor (Q) was evaluated as a function of the accelerating field (Eacc), Lorentz force detuning (LFD), and pressure sensitivity. In the HPR simulations, water droplet dynamics emitted from a 0.5 mm diameter nozzle operating at 100 bar were analyzed as a function of travel distance. The simulations provided detailed estimates of the velocity and impact force of the water jet, which are critical for optimizing cavity surface cleaning.
Paper: WEPS143
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS143
About: Received: 26 May 2025 — Revised: 30 May 2025 — Accepted: 30 May 2025 — Issue date: 06 Jun 2025
WEPS145
Plasma processing of ESS elliptical cavities
2415
Plasma treatment has proven effective in recovering and reducing field emission in the affected superconducting radiofrequency (SRF) cavities. A joint effort is underway between CEA, ESS and INFN to apply this technique to the treatment of elliptical cavities in the ESS linac. This paper presents the work done so far, which aims at both the development of the plasma process for cavities in the cryomodule and the treatment of cavities in the vertical test configuration. The peculiarity of ESS cavities compared with typical cavities at 1.3 GHz is the absence of couplers for higher orders.
Paper: WEPS145
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS145
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
THAN2
Coherent stability and dynamic aperture with strong space charge for the FAIR SIS100 synchrotron
2434
Employing octupole magnets for Landau damping of transverse single-bunch instabilities in synchrotrons often restricts the dynamic aperture due to the excitation of betatron resonances. The situation complicates in the presence of strong direct space charge fields. A notable case is the 1-second accumulation plateau of the heavy-ion synchrotron SIS100 at the Facility of Antiproton and Ion Research (FAIR), which is designed to operate at beam intensities near the space charge limit. This study presents numerical simulations that establish the proposed stabilisation scheme, incorporating self-consistent space charge effects, beam coupling impedance and full lattice tracking. The analysis combines requirements for Landau damping of the resistive-wall instability and tolerable octupole current in relation to dynamic aperture. The results demonstrate effective control of collective effects for the most demanding beam production scheme with ${}^{238}$U${}^{28+}$ beams.
Paper: THAN2
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THAN2
About: Received: 28 May 2025 — Revised: 30 May 2025 — Accepted: 01 Jun 2025 — Issue date: 06 Jun 2025
THYD1
Reinforcement learning in particle accelerators
2438
Reinforcement learning (RL) is a unique learning paradigm inspired by the behaviour of animals and humans to learn to solve tasks autonomously. Learning occurs through interactions with an environment, exploring, and evaluating strategies under various conditions. RL excels in complex environments, can handle delayed consequences, and is able to learn solely from experience without access to an explicit model of the system. This makes RL particularly promising for particle accelerators, where the dynamic conditions of particle beams and accelerator systems require continuous adaptation, and modelling is challenging. Although RL applications are emerging in accelerator physics and showing promising results, their widespread introduction faces critical challenges. Among the main obstacles are the effective formulation of control problems, training, and the deployment of solutions in real systems. This paper provides an overview of the potential of RL in accelerator applications, highlighting current challenges and future research directions.
Paper: THYD1
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THYD1
About: Received: 27 May 2025 — Revised: 30 May 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
THPB001
Conceptual design of the vacuum system of cSTART
2456
The Karlsruhe Institute of Technology (KIT) operates research accelerator facilities for the development of new technologies for future compact light sources at the Institute for Beam Physics and Technology (IPBT). Within the cSTART project (**c**ompact **ST**orage ring for **A**ccelerator **R**esearch and **T**echnology), a Very Large Acceptance compact Storage Ring will be realized to combine a compact storage ring and a laser-plasma accelerator. The new design, based on 45° bending magnets, is suitable to store a wide momentum spread beam. Good vacuum conditions are essential for the successful operation of such an accelerator system. In our case, a final pressure of <1E-8 mbar is required. For cSTART, special care was taken to find a compact (43 m circumference), space- and cost-saving, yet efficient vacuum system design that fulfils this requirement. This article presents the vacuum concept that will be used at cSTART. This includes the selection of vacuum components, the design of the vacuum chamber and vacuum simulations.
Paper: THPB001
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPB001
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
THPB002
Vacuum system of MAX4U – an upgrade of MAX IV 3 GeV storage ring
2460
MAX 4U is an upgrade project of the MAX IV 3 GeV storage ring, to be realized by the early 2030’s in Lund, Sweden. The goal of the upgrade is to reduce the horizontal electron beam emittance to below 100 pm.rad. A new magnet lattice will be used, thus the vacuum system will have to be adapted to follow the new beam orbit of MAX 4U. Several lattices imposing the most severe changes to the beam orbit were studied. One proposal for the MAX 4U vacuum system is to re-use and adapt under vacuum the shape of the MAX IV 3 GeV ring vacuum chambers (coated with non-evaporable getter (NEG) thin film) by bending-to fit to the new magnet lattice. In such scenario, the vacuum system will not be vented, thus the NEG coating will not have to be re-activated. Such approach is very cost-effective and reduces the installation and commissioning time to the minimum. This scenario is presented here, together with the performed simulations, validation studies and tests.
Paper: THPB002
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPB002
About: Received: 16 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
THPB008
Sputtering characteristics of a compact NEG-coating device and performance evaluation of the TiZrV thin films
2474
Non-evaporable Getter (NEG) coating is a breakthrough technology wherein the inner walls of a vacuum chamber are coated with a material that functions as a vacuum pump. This technology is expected to gain widespread adoption across various fields in the future. However, the current coating method, originally developed for long beam ducts, is not adaptable to a wide range of vacuum chamber designs. Therefore, we have developed a compact NEG coating device that can be adapted to chambers of various geometries. The primary advantage of this device is its ability to coat complex-shaped chambers, which was difficult with conventional methods. Additionally, by reducing the uncoated surfaces as much as possible, it significantly improves pumping performance in terms of pumping speed and reducing Photon Stimulated Desorption (PSD) yields. We explore the optimal sputtering conditions for depositing high-performance NEG thin films with the device, and have performance evaluations of the NEG films, with observing the morphologies, measuring the pumping speed and PSD yields.
Paper: THPB008
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPB008
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
THPB011
Design, fabrication, and characterization of 3D-printed photonic crystals for THz filtering applications in particle accelerator
2477
The advancement of broadband terahertz (THz) sources has become increasingly important for various scientific and technological applications, including those in particle accelerators. To enable tunable and flexible THz source development, components capable of selective THz spectrum filtering are essential. In this work, we investigate the use of 3D-printed photonic crystal structures, specifically woodpile designs, for THz filtering applications. Using high-precision digital light processing (DLP) 3D printing, we successfully fabricate woodpile photonic crystals with high accuracy. The fabricated structures demonstrate effective spectral filtering capabilities within the THz range, offering promising potential for applications in advanced accelerator technology and related fields.
Paper: THPB011
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPB011
About: Received: 28 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
THPB015
An evaluation of collimation settings for the High Luminosity LHC baseline
2489
In the context of the High Luminosity Large Hadron Collider (HL-LHC) project, two configurations of collimator settings are being considered. A set of relaxed settings were conceived to address potential limitations due to the impedance contribution of the collimation system with the initially foreseen settings, and to increase the primary betatron cut in case of over-populated beam tails. A significant simulation campaign has been conducted, utilising Xsuite-FLUKA coupling for the first time, to estimate the cleaning performance for each of these settings with the latest optics and layout scenarios. In addition, experiments in the current LHC have been carried out to experimentally study the cleaning performance with HL-LHC settings and to validate the simulated predictions. This paper presents and examines the results of these studies, aiming to determine which collimation settings are more suitable for implementation.
Paper: THPB015
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPB015
About: Received: 28 May 2025 — Revised: 30 May 2025 — Accepted: 30 May 2025 — Issue date: 06 Jun 2025
THPB017
Magnetohydrodynamic effects in liquid lead target concept for Muon Colliders
2493
The use of liquid lead as a target material in particle accelerators is of significant interest due to its high density, high thermal power absorption capacity, and resistance to radiation damage. This makes it particularly well-suited for the high-intensity proton beams being studied for CERN’s Muon Collider proposal, with powers ranging up to 4 MW. To minimize shock propagation and manage the intense thermal and mechanical stresses induced by the high-power proton beam, a free-falling liquid lead curtain is explored as a promising concept. However, the target region requires strong magnetic fields, around 20 T, to re-focus the secondary particles generated at the target, introducing complex magnetohydrodynamic (MHD) effects in the liquid metal flow. These effects, particularly caused by Lorentz forces and MHD losses, present challenges to achieving stable and efficient high-power target systems. This work presents multiphase MHD simulations that reveal flow instabilities and highlight potential concerns within the free-falling curtain concept. The findings provide critical insights into the feasibility of liquid lead targets for high-intensity beams.
Paper: THPB017
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPB017
About: Received: 26 May 2025 — Revised: 31 May 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
THPB018
Conceptual design and optimization of a liquid lead circuit as beamstrahlung absorber for the CERN’s FCC
2497
Beamstrahlung radiation represents a new challenge at CERN's lepton Future Circular Collider (FCC-ee), specifically for electron-positron collisions. At each interaction point, its unprecedented beam intensities give rise to two photon beams with a power of several hundred kW each. Liquid lead, known for its high density and Z and relatively low melting point, is proposed as a beam dump material to safely dispose of this power. Achieving the necessary effective interaction thickness of 10 to 20 cm presents challenges in optimizing both mass flow rates and the geometric configuration of the lead. This study employs the Monte Carlo code FLUKA to simulate energy deposition and thermal simulations to investigate multiphase flow dynamics within an open-channel configuration. Various slope designs for a free-flowing liquid lead stream within an argon-filled vessel are explored to prevent oxidation. By optimizing the slope and shape of the lead flow, this work seeks to enhance energy absorption and thermal management, improving the effectiveness of liquid lead in high-power beam dump applications.
Paper: THPB018
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPB018
About: Received: 26 May 2025 — Revised: 31 May 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
THPB023
Numerical simulation of a modified air conditioning system of the experimental hall at TPS
2509
Taiwan Photon Source (TPS) has been committed to serve users for eight years. In the first and second phases of TPS beamline project, there were 16 beamlines had been in operation. The third phase project had been launched in 2021. Facing the more persons and equip-ment in the experimental hall as well as power saving issue, we applied the computational fluid dynamic (CFD) scheme to simulate the air conditioning system to obtain better cooling efficiency. We modelled one twelfth of the TPS experimental hall and two beamlines.
Paper: THPB023
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPB023
About: Received: 28 May 2025 — Revised: 30 May 2025 — Accepted: 31 May 2025 — Issue date: 06 Jun 2025
THPB030
CFD thermal studies of the air inside the storage ring tunnel of the ALBA synchrotron light source for the 3rd and 4th generation designs
2526
The ALBA Synchrotron is currently designing its new version to become a 4th generation particle accelerator. In this new scenario, ALBA would produce a brighter and more coherent photon beam. As a result, ALBA would provide capabilities hitherto inaccessible in terms of resolution, detection levels and understanding of chemical and electromagnetic properties. In this context, the thermal and geometric conditions inside the tunnel will be modified, specifically the Storage Ring. The Booster Ring, Transfer Lines, Air Conditioning System and the tunnel itself will not be modified. The prediction of the thermal behaviour of the air inside the tunnel for the 4th generation is essential, considering the influence of the stability of the air temperature on the stability of the electron beam orbit. The present work assesses Computational Fluid Dynamics (CFD) studies of the air inside both the current and the 4th generation ALBA tunnel. Comparative studies of the temperature distribution in the air are performed and proposals for the optimization of the air conditioning system are presented. The studies are based on the FLUENT software of ANSYS WORKBENCH.
Paper: THPB030
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPB030
About: Received: 22 May 2025 — Revised: 03 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
THPB034
A radiation-resistant distributed temperature sensor for CERN’s accelerators
2533
Optical Fibre Sensors (OFS) possess unique features, such as high sensitivity, versatility, and the ability to operate in harsh radiation environments. Distributed OFS are notable for enabling real-time monitoring over large-scale facilities, making them ideal for applications in particle accelerators. Their distributed measurement capabilities provide comprehensive monitoring while offering a cost-effective alternative to conventional pointwise technologies. As part of the Innovation work package of CERN’s Personnel Safety System Consolidation program, an experimental study was conducted to characterize the performance of a radiation-hard Distributed Temperature Sensor (DTS) to complement CERN’s safety systems, addressing cryogenic leaks and fire risks. Several fire tests were performed to assess the sensor's accuracy and temporal response under emergency-like conditions. A phenomenological model was derived from these tests to predict the system's behaviour in real-world scenarios. The obtained results are key to the first deployment and operation of a dedicated DTS demonstrator in a part of the LHC in 2025.
Paper: THPB034
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPB034
About: Received: 26 May 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
THPB042
Design and first prototype results of PETRA-IV permanent magnet dipole-quadrupoles
2544
Permanent magnet-based dipoles will be an essential part of the future PETRA-IV light source at DESY. The bending magnets are combined-function DQ-magnets, which provide moderate focusing with a B/G ratio of about 0.03m. Each DQ consists of several C-shaped modules, one of the three types additionally having a stepwise longitudinal gradient. Several prototype modules have recently been manufactured. The paper describes the magnet design, compares manufacturing peculiarities, and discusses first magnetic measurement results.
Paper: THPB042
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPB042
About: Received: 26 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
THPB051
Performance evaluation of additively manufactured pure copper radio frequency quadrupole by low-power RF and high-field gradient tests
2562
This paper presents studies on advanced accelerator technologies conducted under the I.FAST (Innovation Fostering in Accelerator Science and Technology) EU project, focusing on additive manufacturing (AM) advancements. AM, particularly powder bed fusion, is giving unique production capabilities for accelerator components. As a proof-of-principle, a full-size pure copper Radio Frequency Quadrupole (RFQ) was successfully manufactured earlier. Low-power RF tests and bead-pull measurements performed on this prototype confirmed the precise electromagnetic field distribution, validating design accuracy and repeatability. Furthermore, high-field gradient tests conducted in the CERN's DC pulsed measurement system showed that AM copper electrodes spaced of 94 µm can achieve gradients up to 42 MV/m. These promising results highlight the transformative potential of additive manufacturing in producing high-frequency accelerator components, advancing both precision and reliability.
Paper: THPB051
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPB051
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
THPB052
Laser powder bed fusion for x-band RF cavities: A preliminary study
2566
With increasing operational frequency ($f_R$), the size, weight, and power consumption of linear accelerators (Linacs) decrease, which is why e.g. X-band LinVarious studies show that additive manufacturing (AM) has the potential to significantly reduce the cost of radio frequency cavities (cavities) while increasing performance. With increasing resonance frequency, the size, weight, and power consumption of linear accelerators (Linacs) decrease, which is why, e.g. X-Band Linacs are attractive for industry, medicine, and science. This work investigates, for the first time, whether laser powder bed fusion (PBF-LB/M) offers the geometric accuracy necessary for X-Band cavity manufacturing. Eight 9.29 GHz side-coupled test cavities, each comprising three single cells, were fabricated from CuCr1Zr. One of the cavities was post-processed using plasma electrolytic polishing to increase the quality factor. The manufactured cavities were evaluated using a Vector Network Analyze and an optical 3D profiler.
Paper: THPB052
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPB052
About: Received: 28 May 2025 — Revised: 30 May 2025 — Accepted: 31 May 2025 — Issue date: 06 Jun 2025
THPB085
Design and structural analysis of a bending chamber for EPU applications in the SPS-II storage ring
2597
Designing a vacuum chamber for the Elliptically Polarized Undulator (EPU) in the SPS-II storage ring presents challenges due to a constrained bore aperture, minimal clearance between magnet poles, and requirements for synchrotron radiation delivery. This study focuses on a vacuum chamber design that accommodates the large opening angle necessary for EPU operation. A complex transition cross-section was developed to achieve the required beam aperture while maintaining compatibility with the magnet structure. The limited clearance of 0.5 mm between the chamber and magnets necessitates precision machining and fabrication. Structural reinforcements were added to the thin sections of the chamber to ensure mechanical stability, and a specialized welding approach was implemented to minimize deformation. The chamber is fixed to supports designed to control thermal deformation during operation. Finite element analysis (FEA) evaluates the chamber’s structural performance, including stress, safety factors, and deformation, confirming the design meets the operational requirements for EPU applications in the SPS-II storage ring.
Paper: THPB085
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPB085
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
THPB086
New analysis tools for LHC aperture measurements
2600
Aperture measurements at the Large Hadron Collider (LHC) are routine procedures conducted during the early stages of beam commissioning, prior to the injection of high-intensity beams. This is to ensure that the aperture, defining the clearance for the circulating beams, is protected by the LHC collimation system. Local aperture measurements are performed to probe the available aperture at specific locations. Such measurements are carried out by applying a local orbit bump in the area of interest. The bump amplitude is increased until the beam touches the aperture, visible through signals in the local Beam Loss Monitors. This contribution introduces a refined approach to analyse local aperture measurements by incorporating measured beam position monitor (BPM) signals to enhance the precision of the analysis. Using the Xsuite package, the orbit bump is simulated and rematched to the measured BPM signal to enhance the analysis and quantify the uncertainties with respect to the theoretical beam orbit. Using past measurement data, we compare the results obtained using the established and revised methodologies and conclude on derived measurement uncertainties.
Paper: THPB086
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPB086
About: Received: 14 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
THPB087
Overview of IFMIF-DONES lithium target system design
2604
At the core of IFMIF-DONES is placed the Target System. It generates a high-speed liquid lithium jet (15 m/s, 300°C) acting as the target for a 40 MeV, 125 mA deuterium-based linear accelerator, with the primary aim of qualifying fusion-related materials. The design of the Target System has evolved during the last few years addressing key challenges. Managing the 5 MW of power deposited continuously in the target requires a reliable lithium loop supplying liquid lithium in well-defined conditions. The extreme operational conditions, exposed to high irradiation levels (~25 dpa/year), demand also careful selection of materials and regular replacement strategies for critical components, supported by dedicated Remote Handling systems. Current efforts focus on optimizing the design to meet the requirements for its upcoming construction phase. This includes advanced features to facilitate assembly, installation, and long-term operability. Additionally, attention is being paid to the integration of diagnostics. This contribution highlights the recent R&D and engineering solutions aimed at advancing the Target System toward successful construction, commissioning and subsequent operation.
Paper: THPB087
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPB087
About: Received: 27 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
THPB093
Current status of permanent magnet radiation resiliency studies at CEBAF
2614
One possible future for Jefferson Lab’s Continuous Electron Beam Accelerator Facility (CEBAF) lies in upgrading its maximum nominal energy using Fixed-Field Alternating-gradient (FFA) technology for its recirculating arcs. The current proposal aims to use permanent magnets to supply the fixed fields. One concern among reviewers is the degradation of these permanent magnets during operation due to the radiation environment in which they will be present. This work, funded by a Laboratory Directed R&D grant, aims to measure the magnet degradation in the CEBAF tunnel enclosure, and extrapolate to the energies expected from the upgrade. We present the latest results of this study, as well as plans moving forward.
Paper: THPB093
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPB093
About: Received: 27 May 2025 — Revised: 30 May 2025 — Accepted: 31 May 2025 — Issue date: 06 Jun 2025
THPB097
Material properies of 3D-printed copper for rf-cavities
2623
This study investigates the material properties of 3D-printed copper for use in radio frequency (RF) cavities, with a focus on its suitability for high-performance accelerator applications. Key aspects include an analysis of the corrosion and erosion resistance of the printed copper, as well as its electrical and thermal conductivity. Results demonstrate the potential of additive manufacturing for producing RF components while addressing challenges related to material performance under operational conditions. The findings contribute to the development of advanced manufacturing techniques for efficient and durable RF cavity fabrication.
Paper: THPB097
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPB097
About: Received: 29 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
THPB098
Design of the ANTHEM RFQ mechanical supports
2627
The ANTHEM (Advanced Technologies for Human-centered Medicine) research project will establish a Research and Clinical Center in Caserta, Italy, for the study and application of Boron Neutron Capture Therapy (BNCT). The INFN (LNL, Pavia, Napoli, Torino) has in charge the design and construction of the epithermal neutron source, that will assure a flux of $10^9\ n/(s\ cm^2)$ with characteristics suited for deep tumors treatment. The Radio-Frequency Quadrupole (RFQ), designed by INFN, produces $30\ mA$ of protons at $5\ MeV$ and is composed of 3 super modules, each of which at $600\ kg$ in weight and $2.5\ m$ in length. The supports perform the iso-statical alignment during the modules assembly, coupling and alignment, and are also used to align the RFQ respect to the Nominal Beam Line, using a Laser Tracker to monitor the position with a tolerance of $0.1\ mm$. This paper details the chosen kinematic configuration, the supports design, the calculation and simulations for design validation, the procedures for regulation and alignment and the achieved results.
Paper: THPB098
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPB098
About: Received: 22 May 2025 — Revised: 01 Jun 2025 — Accepted: 01 Jun 2025 — Issue date: 06 Jun 2025
THPB101
Study of a girder system for the Korea-4th Generation Synchrotron Radiation (4GSR) accelerator
2633
The Korea 4th-Generation Synchrotron Radiation (4GSR) accelerator requires exceptionally high mechanical stability to ensure reliable beam operation with an extremely small beam size. To achieve this, a robust grid-er system is essential for supporting accelerator components such as magnets, vacuum chambers, and beam position monitors (BPMs). The girder system must suppress vibrations originating from the ground to prevent disturbances in the electron beam trajectory, while also maintaining sufficient mechanical rigidity to support heavy components like electromagnets. In the Korea 4GSR project, the girder system is required to maintain a misalignment tolerance within ±100 μm and limit vibration amplitudes to less than 10% of the beam size to ensure beam stability. However, with a storage ring circumference of approximately 800 meters, meeting these specifications poses significant challenges. This study presents the development of a girder system using finite element analysis (FEA) methods to achieve both mechanical stiffness and adjustability, thereby ensuring the required beam stability.
Paper: THPB101
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPB101
About: Received: 23 May 2025 — Revised: 02 Jun 2025 — Accepted: 06 Jun 2025 — Issue date: 06 Jun 2025
THPM017
Uncertainty-Quantified Machine Model Construction Using Physics-Informed Gaussian Processes and Bayesian Optimization
2668
To construct a closed orbit model for an accelerator ring with intrinsic uncertainty quantification from orbit measurements, a physics-informed Gaussian Process model is proposed based on a stochastic ensemble of MAD-X lattices. Key advantages compared to LOCO (Linear Optics from Closed Orbits) include (1.) uncertainty-enabled orbit prediction in between BPMs (beam position monitors), (2.) fitting of a parameter distribution (dipole-like field errors) which inherently models uncertainty, (3.) incorporation of measurement uncertainty from BPM noise, and (4.) an active learning approach which can be more sample efficient than measuring an orbit response matrix. A case study is presented for the GSI heavy ion synchrotron SIS18 with various simulated applications, in particular constructing an effective machine model with minimal orbit uncertainty around the ring, and orbit correction to achieve minimal deviation at a specific location such as, e.g., the septum to control beam loss during slow extraction. This physics-inspired Gaussian Process regression approach shows potential to be applied to optics correction and further applications beyond closed orbit correction.
Paper: THPM017
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPM017
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
THPM018
Efficient accelerator operation with artificial intelligence based optimization methods
2672
Tuning injectors is a challenging task for the operation of accelerator facilities and synchrotron light sources, particularly during the commissioning phase. Efficient tuning of the transfer line is essential for ensuring optimal beam transport and injection efficiency. This process is further complicated by challenges such as beam misalignment in quadrupole magnets, which can degrade beam quality and disrupt operations. Traditional tuning methods are often time-consuming and insufficient for addressing the complexities of high-dimensional parameter spaces. In this work, we explore the use of advanced AI methods, including Bayesian optimization, to automate and improve the tuning process. Initial results, demonstrated on the transfer line of KARA (Karlsruhe Research Accelerator) at KIT (Karlsruhe Institute of Technology), show promising improvements in beam alignment and transport efficiency, representing first steps toward more efficient and reliable accelerator operation. This study is part of the RF2.0 project, funded by the Horizon Europe program of the European Commission, which focuses on advancing energy-efficient solutions for particle accelerators.
Paper: THPM018
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPM018
About: Received: 28 May 2025 — Revised: 29 May 2025 — Accepted: 30 May 2025 — Issue date: 06 Jun 2025
THPM024
Machine learning-driven longitudinal phase space reconstruction for enhanced beam tuning at LANSCE
2683
The Los Alamos Neutron Science Center (LANSCE) relies on accurate tuning of its Drift Tube Linacs (DTLs) to maintain beam quality and operational efficiency. This work introduces a novel machine-learning-based approach to reconstruct the longitudinal phase space (LPS) at the entrance of DTL Tank 1 using two-dimensional phase scans from Tanks 1 and 2. A Deep Neural Network trained on synthetic datasets generated by GPU-accelerated simulations integrates real-time diagnostic data to infer high-resolution LPS distributions. By solving this inverse problem efficiently, the method improves beam delivery precision while reducing operator intervention. Early results indicate that this approach can enhance LANSCE’s operational capabilities, providing a robust framework for accelerator tuning and diagnostics.
Paper: THPM024
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPM024
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
THPM030
Characterization of four-dimensional phase space for space charge-dominated beams using novel beam diagnostic techniques and generative phase space reconstruction at the KOMAC beam test stand
2693
Transverse phase space (x, x’, y, y’) measurement is crucial in beam physics to optimize the beam parameters. Typically, the phase space information of space charge-dominated beams can be characterized using well-established methods such as pepper-pot and movable slit-based scans. In addition, recent studies show that calibration of transfer matrix with considering space charge forces provides quantitative agreement in a solenoid scan-based emittance measurement. In this study, we characterize the space charge-dominated, 1 MeV/n proton beam at the Beam Test Stand (BTS) of Korea Multipurpose Accelerator Complex (KOMAC) using various beam diagnostic instruments such as pepper-pot, virtual pepper-pot, and multi slits. Furthermore, we investigate the usage of generative phase space reconstruction, based on neural networks and differentiable simulations, in the context of space-charge calibrated matrix computations and self-consistent beam propagation. We also discuss the comparison of the phase spaces obtained by conventional diagnostics, confirming the effectiveness of the reconstruction algorithm and advanced diagnostic methods for analyzing space charge-dominated beams.
Paper: THPM030
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPM030
About: Received: 28 May 2025 — Revised: 31 May 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
THPM044
Selecting 1D projections for 2D tomography reconstruction
2731
Previous works on reconstructing the 4D phase space using tomography require optimal selection of projection views to achieve accurate reconstruction. In 2D reconstruction, the process is straightforward, as an object can be evenly sampled by dividing the angles evenly. However, extending this concept from 2D to 4D is not intuitive. This work demonstrates that quaternions can be used to more effectively describe views in 4D and introduces the Fibonacci Flower algorithm and repulsive force algorithm to evenly space views in 4D space in order to achieve higher reconstruction accuracy.
Paper: THPM044
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPM044
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
THPM057
A full digital beam position and phase measurement signal processing algorithm based on FPGA designed for linear accelerator
2754
A new digital beam position and phase measurement (BPM) system was designed for the ion-Linac (iLinac) accelerator in the High Intensity heavy ion Accelerator Facility (HIAF). The fundamental and the second harmonic signals are retrieved from the BPM electrodes to simultaneously calculate their respective beam positions and phases. All data acquisition and digital signal processing algorithm routines are performed in a field programmable gate array (FPGA). The position and phase information are obtained by using the in-phase and quadrature (IQ) demodulation method. A practical and straightforward method is used to generate the second harmonic reference signal for processing the second harmonics beam signal. The reconfigurable filters are integrated into the FPGA to allow the measurement of short beam pulse length. The laboratory test results show the achieved phase resolution is better than 0.2$^{\circ}$ and 0.03$^{\circ}$ when the input signal is -60 dBm and -45 dBm respectively. A position resolution better than 30 $\mu$m was achieved for an input power level of approximately -60 dBm, and it can reach 7 $\mu$m with the input power higher than -45 dBm. The entire execution time of the algorithm is accomplished within 3.4 $\mu$s, which provides a sufficient reaction time for the fast beam interlock signal to the machine protection system (MPS). The performance of this newly designed prototype BPM electronics was evaluated with the online proton beam.
Paper: THPM057
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPM057
About: Received: 29 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
THPM063
Extended phase space tomography for EOSD simulation considering crystal geometry effects
2768
This theoretical study presents an advanced method for longitudinal phase space tomography in electron storage rings, focusing on reconstructing phase space densities from electro-optical spectral decoding (EOSD) measurements that incorporate crystal geometry effects. The EOSD crystal geometry significantly impacts the measurement signal due to signal integration along its length and interference from wake fields and Cherenkov diffraction radiation (ChDR). These effects add challenges to reconstructing the original phase space density from experimental data. To address these challenges, we integrate two theoretical frameworks. First, we employ the Vlasov-Fokker-Planck equation to model the turn-by-turn evolution of the charge density distribution. Second, CST simulations of the bunch profile characterize the electric field inside the crystal, enabling a tailored simulation for the EOSD system at the Karlsruhe Research Accelerator (KARA). By combining these approaches, we propose a refined tomography method that more accurately reconstructs the longitudinal phase space from sensor data, effectively capturing the interplay between bunch dynamics and the EOSD system configuration.
Paper: THPM063
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPM063
About: Received: 23 May 2025 — Revised: 01 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
THPM077
Measurement of vertical and horizontal emittance via undulator high harmonics at the APS-U
2802
The transition from 3rd to 4th generation synchrotron light sources can primarily be characterized by a significant reduction in horizontal emittance. This enables a nearly uniform transverse X-ray beam profile and a brilliance that approaches the diffraction limit. A consequence of the upgrade to Diffraction Limited Storage Rings (DLSRs) is that the traditional emittance measurement techniques lack the resolution required to accurately measure emittances in the picometer-radian range. At the Advanced Photon Source Upgrade (APS-U), we explore the use of high harmonics of undulator radiation for precise emittance characterization. Previously at the Advanced Photon Source (APS), vertical emittance measurements, validated through SPECTRA simulations, were performed. This drove the desire to measure the horizontal emittance at the APS-U. Simulations performed in SPECTRA and Synchrotron Radiation Workshop (SRW) guide our experimental strategy for characterization. We present measurements of both the horizontal and vertical emittance at the APS-U, including variations across different bunch timing modes. We conclude by discussing the advantages of this approach over traditional methods.
Paper: THPM077
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPM077
About: Received: 28 May 2025 — Revised: 31 May 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
THPM085
Design and development of a beam scraper system for Siam Photon Source II
2806
This paper presents the development of a beam scraper system for the 3 GeV storage ring of Siam Photon Source II (SPS-II). Beam scrapers are essential for removing halo particles, protecting accelerator components, and managing aperture limitations. The scraper blade material is carefully chosen for its superior thermal conductivity and mechanical strength. The design prioritizes considering wakefield impedance to minimize beam disturbances, incorporates detailed thermal simulations to ensure operational stability, and optimizes the mechanical structure for easy installation and long-term durability. This design approach significantly enhances the performance and reliability of the SPS-II beam scraper system.
Paper: THPM085
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPM085
About: Received: 28 May 2025 — Revised: 30 May 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
THPM087
Possibilities for performance enhancement of a compact TDS at FLUTE
2812
A compact transverse-deflecting system (TDS) is being commissioned at the test facility FLUTE (Ferninfrarot Linac- und Test-Experiment) located at the Karlsruhe Institute of Technology (KIT). It has been proposed for diagnostics of short electron bunches. The idea of the technique is to use terahertz (THz) radiation, produced by the tilted-pulse front method using a part of the facility’s photoinjector laser, amplified by a sub-mm scale resonator for streaking of the electron bunch. Two types of resonators and their arrays have been studied: inverse split-ring and tilted slit resonator. Since the temporal resolution of this technique depends strongly on the electric field strength in the resonator gap, it would be desirable to increase this field strength. A horn-antenna-like device placed near the resonator has been proposed and simulated for this purpose. Simulations and geometrical parameter optimization have been performed using CST MICROWAVE STUDIO and will be presented in this contribution.
Paper: THPM087
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPM087
About: Received: 28 May 2025 — Revised: 01 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
THPM095
Benchmarking of new approach for analyzing transverse beam emittance measurement
2832
A recent analysis of emittance measurements highlighted the limited reliability of tools for precise method evaluation and error calculations. In this paper, a new analysis method is presented with its associated errors calculations. It is evaluated using realistic beam simulations and compared to the linear regression method commonly referenced in the literature. This new analysis method is shown to be easier to implement and provides results with a good confidence interval.
Paper: THPM095
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPM095
About: Received: 22 May 2025 — Revised: 02 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
THPM096
Top-up safety simulations for Elettra 2.0
2836
A comprehensive program of tracking studies has been carried out to ensure that no train of injected electron bunches can traverse an open beamline during top-up operations at Elettra 2.0. The analysis explored various error scenarios, considering realistic magnetic field variations, trajectory shifts, aperture constraints, and energy deviations. This paper presents the tracking techniques employed, the scenarios investigated, and the proposed interlock systems designed to ensure safety during top-up operations.
Paper: THPM096
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPM096
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
THPM101
Unified differentiable digital twin for the IOTA/FAST facility
2851
As the design complexity of modern accelerators grows, there is more interest in using advanced simulations that have fast execution time or produce insights about accelerator state. One notable example of additional information are gradients of physical observables with respect to design parameters produced by differentiable simulations. The IOTA/FAST facility has recently begun a program to implement and experimentally validate a unified start-to-end differentiable digital twin to serve as a virtual accelerator test stand, allowing for rapid prototyping of new software and experiments with minimal beam time costs. In this contribution we will discuss our plans and progress. Specifically, we will cover the selection and benchmarking of both physics and ML codes, the development of generic interfaces between device models and surrogate or physics-based sections, and the export of the parameters through either a deterministic event loop or a fully asynchronous EPICS soft input/output controller. We will also discuss challenges in model calibration and uncertainty quantification, as well as future plans to support larger proton accelerators like PIPII and Booster.
Paper: THPM101
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPM101
About: Received: 29 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
THPM102
High efficiency multi-objective Bayesian algorithm for APS-U nonlinear dynamics tuning
2855
The Advanced Photon Source (APS) facility has just completed an upgrade to become one of the world’s brightest storage-ring light sources. Machine learning (ML) methods have seen extensive use during commissioning. One important application was multi-objective tuning of dynamic aperture and lifetime, a complex high-dimensionality task intractable with classic optimization methods. In this work we will discuss novel Bayesian optimization (BO) algorithmic and implementation improvements that enabled this use case. Namely, pre-training and uncertainty-aware simulation priors, dynamic parameter space and acquisition function refinement, and an adaptive wall-time convergence criteria. We will also show results of optimization runs from 10 to 24 dimensions, benchmarking scaling and efficiency as compared to standard MOGA and MGGPO. Given the promising performance, work is proceeding on tighter BO integration into the control room.
Paper: THPM102
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPM102
About: Received: 29 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
THPM113
Trajectory steering for DC beams at the CERN SPS using reinforcement learning based on intensity measurements
2878
The slow extracted beams at the CERN Super Proton Synchrotron (SPS) are transported over several 100 m long transfer lines to three targets in the CERN North Area Experimental Hall. The experiments need intensity fluctuations to be entirely eliminated over the roughly 5 s particle spill, requiring full debunching of the extracted beams. In this environment, secondary emission monitors (SEMs) have to replace the conventional beam position monitoring systems that rely on RF structure, with the intensity difference on split secondary emission foils used to indicate the beam position. Traditional trajectory correction algorithms however fail when the beam ends up on a single foil. This paper summarises successful first tests with reinforcement learning (RL) to learn to correct the trajectory based on foil intensity measurements. The RL agents were trained in simulation and then successfully transferred to the real accelerator environment. Results of the application of the trained RL agents for the alignment of moveable split foils in front of the targets will also be presented.
Paper: THPM113
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPM113
About: Received: 26 May 2025 — Revised: 02 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
THPM116
Efficient data-driven model predictive control for online accelerator tuning
2881
Reinforcement learning (RL) is a promising approach for the online control of complex, real-world systems, with recent success demonstrated in applications such as particle accelerator control. However, model-free RL algorithms often suffer from sample inefficiency, making training infeasible without access to high-fidelity simulations or extensive measurement data. This limitation poses a significant challenge for efficient real-world deployment. In this work, we explore data-driven model-predictive control (MPC) as a solution. Specifically, we employ Gaussian processes (GPs) to model the unknown transition functions in the real-world system, enabling safe exploration in the training process. We apply the GP-MPC framework to the transverse beam tuning task at the ARES accelerator, demonstrating its potential for efficient online training. This study showcases the feasibility of data-driven control strategies for accelerator applications, paving the way for more efficient and effective solutions in real-world scenarios.
Paper: THPM116
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPM116
About: Received: 27 May 2025 — Revised: 02 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
THPS012
Interaction point beam offset tolerances for luminosity performance at FCC-ee
2922
To achieve physics performance at the Future Circular electron-positron Collider (FCC-ee), luminosity and beam lifetime must be maintained at close to design specifications. Alongside global feedbacks, a fast feedback system is proposed to mitigate beam offset errors at the interaction points (IP), caused by magnet vibrations or other time-varying errors. In this paper, the FCC-ee luminosity performance is simulated for beam-beam interactions including beam offsets, providing performance requirements for the fast feedback system.
Paper: THPS012
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPS012
About: Received: 26 May 2025 — Revised: 01 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
THPS017
Design and validation of a micrometric and adaptable calibration bench for frequency scanning interferometry sensors
2938
The High-Luminosity Large Hadron Collider (HL-LHC) project at CERN aims to enhance the LHC's performance and increase its discovery potential. As part of this upgrade, new components will be installed and must be aligned with an accuracy of 0.17 mm vertically and 0.33 mm radially (1σ) over a length of 420 m. To achieve such requirements in harsh conditions, CERN has developed a range of new sensors using Fourier analysis-based Frequency Scanning Interferometry (FSI), capable of absolute distance measurements on multiple targets within a few micrometers’ uncertainty. More than 600 of these FSI sensors will be deployed for the project, necessitating an accurate, fast, adaptative and cost-effective calibration of these sensors. To do so, a specialized calibration bench has been developed. This paper details the design, benchmarking, and final validation of this calibration bench, which enables rapid calibration of a wide range of FSI sensors to an accuracy below 10 μm (1σ). Additionally, it presents the first intense use of this bench in the frame of the Inner Triplet String test, a facility representing one complete section of new focusing regions of the HL-LHC upgrade project.
Paper: THPS017
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPS017
About: Received: 23 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
THPS050
Development of a flexible digital twin framework for accelerators using design patterns
3026
These days designing an accelerator consist of prototyping and testing adequate commissioning software. Digital twins serve as natural test benches for validating and monitoring the required physics software stack. These twins must align with the current design state of the accelerator from the project's inception to the machine's commissioning. The authors have developed a modern digital twin framework based on software design patterns. Its architecture emphasizes clean design principles with minimal coupling between components. Its setup requires only lattice and device configuration data. Thanks to its design, it seamlessly integrates into prototyping environments or control system infrastructures. In this paper, we briefly describe the design patterns underlying this architecture, highlight the flexibility and advantages of the infrastructure, and outline the steps needed to implement it for a machine currently lacking a digital twin.
Paper: THPS050
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPS050
About: Received: 25 May 2025 — Revised: 01 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
THPS053
Integrating community codes for accelerator design and optimization
3029
Advances in fidelity and performance of accelerator modeling tools, in tandem with novel machine learning capabilities, has prompted community initiatives aiming to realize “virtual test stands” that can serve as true analogues to physical machines. Such efforts require integrated, end-to-end modeling capabilities with support for parametric optimization and benchmarking. We present the ongoing development of an integrated Sirepo application to support the holistic modeling of accelerators. Our approach leverages existing modeling workflows, such as the Light Source Unified Modeling Environment (LUME), as well as community I/O frameworks, such as openPMD, to provide a toolbox for constructing and modeling beamlines. Users can build and test simulations using different community modeling tools, as well as connect individual tools to produce end-to-end simulations. Additional workflows have been developed to support machine learning tools that facilitate optimization and the development of surrogate models. We discuss some specific beamline modeling demonstrations as well as ongoing efforts to support code-agnostic design and development.
Paper: THPS053
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPS053
About: Received: 29 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
THPS058
Cryogenic inserts in the room temperature synchrotron SIS18 at GSI
3040
The existing room temperature heavy ion synchrotron SIS18 at GSI will be used as booster for the future SIS100 at FAIR. One of its features the the generation of high intensity heavy ion beams. In order to create such beams, medium charge states are used, which have a lower space charge limit and can be created with less stripping losses. Unfortunately, such heavy ions have very high ionization cross sections in collisions with residual gas particles, yielding in beam loss and subsequent pressure rises via ion impact stimulated gas desorption. Although an extensive upgrade plan, including NEG-coated magnet chambers and an ion-catcher system, has been realized, the required intesity goals will not yet be reached. Simulations including cryogenic surfaces around the ion catchers show, that their high sticking probability prevents from pressure built-ups during operation. A prototype ion catcher, including such cryogenic surfaces cooled by a commercial cold-head has been developed, built, and tested. It has recently been installed in SIS18 and will undergo further tests, including measurements with heavy ion beams. Findings for the operation and further cryogenic inserts are presented.
Paper: THPS058
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPS058
About: Received: 20 May 2025 — Revised: 30 May 2025 — Accepted: 31 May 2025 — Issue date: 06 Jun 2025
THPS066
PAnTHer: An interactive map for the web and touchscreens
3054
PAnTHer (Particle Accelerator on THreejs) is a 3D and 2D map for particle accelerators developed using web and touch technologies. The maps are connected to real-time data from accelerator controls, simulators, and an external component database. The map is generated from a lattice file in JSON format and a bundle of JavaScript components for the 3D version, and an SVG bundle for the 2D version. The JSON lattice file can be generated on the fly taking all necessary parameters from a simulator device server and presented instantly to the remote user among with the visualization of some simulated quantities such as position, beta, eta, mu and sigma Available components are: magnets (bending, quadrupoles, sextupoles, correctors, etc.), pumps, valves, PLCs, racks, mirrors, walls etc. Multiple components can be embedded within a single element. The 3D version offers various configurations, ranging from a fast mode, which runs smoothly even on devices with limited computational power, to a standard mode with enhanced graphical details, and a high resolution mode that uses components derived from mechanical department. The latter requires fairly powerful hardware to maintain optimal fluidity.
Paper: THPS066
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPS066
About: Received: 27 May 2025 — Revised: 30 May 2025 — Accepted: 30 May 2025 — Issue date: 06 Jun 2025
THPS071
Analysis of noise spectra color on machine learning denoising algorithms
3058
Previous work has shown the efficacy of using machine learning for removal of noise in LLRF signals when operating in an industrial environment. Here we extend the analysis to include different noise power spectra. Specifically we analyze the impact on denoisig when correlated noise power spectra are used. Four different noise spectra are analyzed including red, pink, violet, and blue noise. We demonstrate the ability to remove the noise when trained on only white noise and compare this to results when retraining on different color spectra.
Paper: THPS071
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPS071
About: Received: 28 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
THPS073
Developing an Object Detector Using Synthetic Data from CAD Models
3063
This work investigates the potential of using synthetic images generated from CAD models to train an object detector for identifying components of a particle accelerator. The study focuses on magnets within the new ALS Accumulator Ring at Lawrence Berkeley National Laboratory. Generating large volumes of real-world training data is often challenging in such complex systems. To address this, CAD files were converted into 3D models and used to produce diverse synthetic datasets. These datasets were augmented with a smaller set of real-world images to train a YOLOv8-based model. This approach aims to evaluate whether synthetic images can effectively support the development of object detectors in environments where real data collection is limited. The study lays the groundwork for future development of real-time recognition tools to assist accelerator operations.
Paper: THPS073
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPS073
About: Received: 28 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
THPS078
Measuring single-pass dispersion in the LHC
3067
During the LHC Ion Run in 2023, the ALICE detector observed a high level of background that prevented efficient data taking. This background was caused by different ion species generated in the betatronic collimation region that were intercepted by the Tertiary collimator near ALICE Interaction Point. The mass-to-charge ratio of these generated ions causes them to follow a different trajectory to the main ion beam, similar to off momentum particles. Since this is a single-pass effect, the closed dispersion does not describe the trajectory of these ions. Instead, the single-pass or one-pass dispersion is the relevant quantity to measure. In this paper two methods for reconstructing the single-pass dispersion based on the closed orbit and optics data are described. The methods are validated through simulations and applied to real data from the LHC 2023 Ion Run.
Paper: THPS078
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPS078
About: Received: 27 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
THPS082
Impact of beam background and jitter on LUXE interaction point
3075
LUXE is an international project that aims to study Quantum Electro-Dynamics processes that occur in the strong field regime. Using the electron beam from the European XFEL, this experiment will perform electron-laser and photon-laser collisions. Beamline simulations are required to understand what beam properties and backgrounds are expected at key locations. The beam optics was design and simulated with MAD-8 and this used to create a BDSIM simulation. To perform high precision interactions it is crucial that the transverse size and position of the electron beam can be measured. The variation of the beam position over time also has impacts on an efficient collision with the laser. This study uses simulated virtual measurement, wire scanning methods, and real measurements at the XFEL to evaluate those parameters. Finally, background from both the upstream beam line and the different dumps must be estimated to ensure that the impacts on the experiment are low enough. This paper present BDSIM simulations with high statistics necessary to evaluate the background. Critical for BDSIM studies is finding optimised ways to do cross-section biasing and final state splitting in the dumps.
Paper: THPS082
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPS082
About: Received: 27 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
THPS110
Advancing accelerator science through data-intensive research and training
3135
The Liverpool Centre for Doctoral Training in Innovation in Data Intensive Science (LIV.INNO) has made significant progress in applying data-intensive methods to accelerator research. This contribution presents research outcomes from the center with a focus on two key projects. The first focuses on optimizing 3D imaging for medical and industrial applications, integrating Monte Carlo simulations and advanced collimation techniques to enhance low-dose, portable X-ray systems, with implications for wider accelerator diagnostics. The second lever-ages deep learning models to reconstruct transverse beam distributions at CERN, addressing challenges in image distortion from multimode optical fibers under high-radiation conditions. The results are connected with wider progress made in machine learning and artificial intelligence for particle accelerators. Furthermore, the paper summarizes the outcomes of several key LIV.INNO events: the STFC Summer School on Data Intensive Science, the LIV.INNO 2024 Industry Showcase and the 2025 AI for Innovation Summit.
Paper: THPS110
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPS110
About: Received: 28 May 2025 — Revised: 31 May 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025