emittance
MOZN1
Overview of permanent magnet implementations for advanced light sources
42
The utilization of permanent magnets in the design of accelerator magnets has witnessed a surge in prominence, particularly within the realm of advanced light sources. Following pioneering initiatives at SIRIUS and ESRF-EBS, current projects are increasingly embracing permanent magnet technology. Notably, in the case of SLS2.0, over 30% of the magnets in the new storage ring are powered with permanent magnets. Permanent magnets offer manifold advantages, including compactness, much simpler requirements in terms of services (such as power supplies, cables, and cooling systems), and reduced operational costs. Nonetheless, they also present significant challenges that demand careful consideration. In this study, the author provides an overview of permanent magnet implementations across various projects and delves into a detailed analysis of the Swiss Light Source upgrade.
Paper: MOZN1
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOZN1
About: Received: 02 Jun 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
MOPB006
Optimal beam energy for ultra low emittance storage rings
76
As new synchrotron light sources push for lower emittances, intra-beam scattering (IBS) becomes an increasingly more important factor in determining the final beam distribution properties. Because IBS depends strongly on beam energy, in the regime of ultra-low emittance rings, beam energy is a parameter to be optimized for best beam performance. In this report, we study the optimal beam energy for various lattices and its dependence on bunch lengthening and damping wigglers.
Paper: MOPB006
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB006
About: Received: 25 May 2025 — Revised: 31 May 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
MOPB033
A novel design of a magnetic chicane with positive R56
123
It has been attracting attention that the energy chirp, which is formed by the space-charge effect of the electron beam and the beam wake field when the beam passes through the accelerator tube, can be used to generate short-pulse XFELs. Since the energy chirp produced by this phenomenon is such that the energy of electrons in the rear of the bunch is lower than at the front, compression requires a magnetic chicane with a positive R56, which shortens the path of the lower energy electrons. On the other hand, a normal simple electromagnetic chicane would have a negative R56, not applicable to this bunch compression. In this presentation, we report on the idea of a compact R56-positive magnetic chicane that can be inserted in a straight section and the results of its design study.
Paper: MOPB033
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB033
About: Received: 27 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
MOPB041
CW SRF gun generating beam parameters sufficient for CW hard-X-ray FEL
147
SRF CW accelerator constructed for Coherent electron Cooling project at Brookhaven National Laboratory frequently demonstrated record parameters using 1.5 nC 350 psec long electron bunches, typically compressed to FWHM of 30 psec using ballistic compression. In this paper we report experimental demonstration of CW electron beam with parameters fully satisfying all requirements for hard-X-ray FEL and significantly exceeding those demonstrated by APEX LCLS II electron gun. The most remarkable part of this achievement in this experiment that we used 10-years old SRF gun with modest accelerating gradient ~ 15 MV/m, a bunching cavity followed by basilic compression to generate 50 pC, 15 psec electron bunches with normalized emittance of 0.15 mm mrad and normalized project emittance of 0.2 mm mrad. In other words, we are presenting alternative method of generating CW electron beams needed for hard-X-ray FELs using existing and proven accelerator technology. We present description of the accelerator system setting, details of projected and slice emittance measurements as well as relevant beam dynamics simulations.
Paper: MOPB041
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB041
About: Received: 30 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
MOPB049
Characterisation of beam dynamics sensitivity to misalignments in the PERLE injector
158
High current linear accelerators require the precise alignment of accelerating cavities to maintain a high beam quality. The PERLE (Powerful Energy Recovery Linac for Experiments) injector cryomodule is composed of four single-cell cavities, each of which can be independently tuned to allow greater control of the beam at this crucial point. Misalignments can lead to perturbations in the beam trajectory and contribute to an increased emittance and energy spread. Here we present a characterisation of the beam dynamics when various misalignments are applied in the injector. Various misalignments are applied, three in the translation axis (x, y, z), and two rotationally, yaw and pitch (𝚽, 𝚹). A study was conducted to determine the tolerances required misalignments to ensure an acceptable beam quality is maintained at. The results indicate that particular combinations of rotational and translational misalignments are especially detrimental to emittance. These findings provide an important guide for the subsequent design of the booster linac and alignment procedure.
Paper: MOPB049
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB049
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
MOPB055
Exploring lattice candidates for TPS upgrade
169
The design of lattice candidates for the Taiwan Photon Source (TPS) upgrade is under investigation, focusing on Multi-Bend Achromat (MBA) and Hybrid Multi-Bend Achromat (HMBA) configurations. A 5BA lattice, which offers relaxed hardware requirements, can achieve a natural beam emittance in the hundred pm-rad range for a 3 GeV storage ring. The 6BA configuration shows promise in achieving phase cancellation without the need for harmonic sextupoles but presents challenges due to limited available space. The HMBA scheme is attractive for its simpler configuration and reduced reliance on nonlinear magnets. Preliminary results highlight the characteristics and trade-offs of each configuration, providing guidance for the future TPS upgrade.
Paper: MOPB055
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB055
About: Received: 27 May 2025 — Revised: 30 May 2025 — Accepted: 30 May 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
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
MOPB100
An alternative lattice for the ZIPS storage ring
232
Since synchrotron radiation sources have many advanced characteristics such as high radiation power, high brightness, broad spectral range, transverse coherence, and excellent time structure, they have become powerful tools for exploring microscopic material structures. With the growing demand for industrial researches, several dedicated industrial light sources are under operation or construction around the world. Zhejiang Industrial Photon Source (ZIPS) is designed to provide a scientific platform for industrial applications within the X-ray region in China. As a preliminary design, the ZIPS storage ring adopts a modified Triple-Bend Achromat (TBA) lattice with an energy of 2.6 GeV and a low emittance of 3.88 nm · rad. Details of the lattice design are presented in this paper.
Paper: MOPB100
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB100
About: Received: 10 Apr 2025 — Revised: 30 May 2025 — Accepted: 02 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
MOPM016
Comparison of BCMS and standard beams at LHC injection energy
303
During the Large Hadron Collider (LHC) run in 2024 two beam types were used for physics production with protons. A key difference between the standard 25 ns and the batch compression merging and splitting (BCMS) beams at injection into the LHC, is the smaller transverse emittance achieved with the latter in the injector chain. Despite both beam types appearing indistinguishable in the longitudinal plane, the BCMS beam caused significantly higher beam losses at the start of the acceleration ramp. For the High-Luminosity LHC (HL-LHC) era, start-of-ramp losses could a limitation due to a lack of RF power. It is therefore important to understand the origin of the increase, as both beam types may be used for operational runs after the HL-LHC upgrade. Systematic analysis of the emittance evolution in all three planes have been conducted to investigate the contribution from loss mechanisms like intra-beam scattering (IBS) and RF background noise. Furthermore, estimates of the beam population outside the bunches and start-of-ramp losses are provided to understand the differences in the off-momentum population before the ramp.
Paper: MOPM016
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM016
About: Received: 26 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
MOPM017
Do transverse bunch tails produce luminosity?
307
Heavily populated transverse beam tails can be an issue for the operation and the performance of present and future particle colliders. In this respect, the tailoring of beam distributions through transverse halo scraping is a powerful technique for limiting beam losses and maximizing beam lifetime. By doing so, a portion of the bunch intensity is sacrificed, to the benefit of a reduced bunch transverse emittance. In this paper, we assess the impact on the luminosity performance of the LHC using such bunches, based on an analytical approach supported by numerical integration. In particular, we quantify the interplay between beam scraping, bunch intensity loss, transverse emittance reduction and collider luminosity performance.
Paper: MOPM017
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM017
About: Received: 26 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
MOPM028
Interplay between sextupole settings and single particle instabilities during the FCC-ee commissioning
351
The Future Circular Collider of electrons and positrons (FCC-ee) is designed to achieve high luminosity at center-of-mass energies ranging from the Z boson peak to the top quark threshold. During the commissioning phase, specialized optics are essential to accommodate the dynamic needs of machine tuning and beam stabilization. This paper investigates the role of sextupoles in the various FCC-ee commissioning optics, focusing on their influence on nonlinear beam dynamics. Using advanced simulation tools, we analyze how sextupole configurations impact key performance indicators, including the dynamic aperture, emittance evolution and lifetime. Strategies for optimizing sextupole strengths are explored. The findings provide critical insights for the design and optimization of the commissioning optics, ensuring efficient and reliable ramp-up to nominal operation. These results are instrumental in refining the FCC-ee commissioning strategy, supporting its broader objectives for particle physics research.
Paper: MOPM028
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM028
About: Received: 27 May 2025 — Revised: 03 Jun 2025 — Accepted: 04 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
MOPM044
Long-term alignment stability of the SuperKEKB tunnel
411
SuperKEKB is a double ring collider consisting of a 7 GeV electron ring and a 4 GeV positron ring with a circumference of 3 km built 11 m below the ground level. SuperKEKB was constructed by reusing the KEKB tunnel, which was originally excavated for TRISTAN accelerator in early 1980s. SuperKEKB utilizes “large angle nano-beam scheme,” where two low emittance beams collide with a large crossing angle at the interaction point and therefore it is more sensitive to any machine errors, such as magnet misalignment, than KEKB. Since the tunnel was built on soft ground, it has been seen that the initial magnet alignment is deteriorating year by year. Level changes of the monument markers on the tunnel wall and the floors on either side of the interaction point have also been observed. The vertical and horizontal positions of the cantilever cryostats of the final focusing superconducting magnet system are constantly monitored during the beam commissioning. The cryostat vertical position presents a correlation with the vertical vertex position in the Belle II detector. These variations and the effects of temperature and other environmental factors on alignment will be reported.
Paper: MOPM044
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM044
About: Received: 20 May 2025 — Revised: 30 May 2025 — Accepted: 31 May 2025 — Issue date: 06 Jun 2025
MOPM082
Phase space measurements of 90 mA and 52.5 keV H⁻ ion beam at J-PARC frontend
503
A 90-mA and 52.5-keV negative hydrogen ion (H⁻ ion) beam has been extracted from the J-PARC Radio Frequency (RF) H⁻ ion source. The 90-mA beam phase-space distribution at the entrance of the Radio Frequency Quadrupole (RFQ) cavity was measured at the test stand. Compared with the 60-mA beam condition for the present J-PARC user operation, reasonable increase in the operation parameters (the RF input power to the ion source, the electrostatic voltage for beam extraction, and the solenoid currents for Twiss matching with the RFQ) was observed. The normalized RMS emittance increased by a few 10 %, which is within the acceptable range of the RFQ. In addition, the dependence of the beam phase-space distribution was investigated with respect to the operation parameters. Numerical analyses show that the optimum solenoid current was determined to remove the beam halo component with the orifice in the beam transport section, which was originally installed for the differential vacuum pumping of the ion source and the RFQ. In the presentation, the effect between the beam current and the phase-space distribution are discussed in aspect of the H⁻ ion beam optics.
Paper: MOPM082
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM082
About: Received: 28 May 2025 — Revised: 29 May 2025 — Accepted: 30 May 2025 — Issue date: 06 Jun 2025
MOPM087
Design of the FCC-ee injector linacs up to 20 GeV beam energy
516
The FCC-ee injector complex aims to deliver tunable, high-charge electrons and positron bunches for injection into a collider operating at center-of-mass energies from 90 to 365 GeV. The injector complex includes multiple linacs that sequentially boost the energy of the bunches to the booster injection energy of 20 GeV. This work addresses the significant challenges posed by the required beam parameters. We designed the electron (up to about 3 GeV) and the high energy (up to 20 GeV) linacs to provide very limited emittance growth due to static imperfections, maximum acceleration efficiency, excellent stability of the beam transverse jitter, and to match the requirements on the bunch length and single- and multi-bunch energy spread as well. An energy compressor system has been foreseen, to provide flexibility to scan beam charges across a wide range without compromising the final energy spread. This paper summarizes the comprehensive design and optimization studies conducted, demonstrating that the proposed linac system meets all current requirements for efficient injection into the booster ring, paving the way for the ambitious operational goals of the FCC-ee accelerator complex.
Paper: MOPM087
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM087
About: Received: 26 May 2025 — Revised: 28 May 2025 — Accepted: 29 May 2025 — Issue date: 06 Jun 2025
MOPS005
Adiabatic capture in high-intensity, high-power rings
578
Finding the optimal RF voltage ramp to capture coasting beams in high intensity rings has been the subject of ongoing study for many decades. We are motivated to revisit the topic with a view to capturing coasting, stacked beams in a future high intensity, high power FFA. However, the results have general applicability. We compare various voltage laws including linear, bi-linear and iso-adiabatic through simulation and experimentally, making use of the ISIS synchrotron. Making use of longitudinal tomography, we seek to establish the voltage program that minimises the captured beam emittance.
Paper: MOPS005
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS005
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 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
MOPS023
Design of the front-end complex for a muon cooling demonstrator at CERN
629
The muon collider has great potential for enabling high-luminosity multi-TeV lepton-antilepton collisions provided low-emittance, high-intensity muon beams can be produced. Ionization cooling is the proposed technique to achieve the required muon beam emittance. The International Muon Collider Collaboration aims to demonstrate the integration and reliable operation of a 6D ionization cooling system, including RF acceleration in strong magnetic fields. This study focuses on the design of the muon production and transport systems for a Muon Cooling Demonstrator facility in the CERN TT7 tunnel. A new implementation based on the CTF3 building is also presented, offering improved layout flexibility and beam intensity. FLUKA simulations are used to optimize the target and magnetic horn geometries to maximize pion production and capture, assuming a 14 GeV proton beam from the Proton Synchrotron (PS). The transport line, designed to deliver 190 – 210 MeV/c muons into the cooling channel, consists of a short pion decay section, followed by a momentum-selecting chicane and a matching section. The chicane integrates collimation and phase-rotation systems for transverse and longitudinal tuning of the muon beam. Beam optics for the transport lattice are designed in MAD-X, with tracking studies performed using BDSIM.
Paper: MOPS023
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS023
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 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
MOPS034
Increasing single-bunch intensity limit at ESRF-EBS with high coupling
665
Synchrotron radiation light sources normally operate at a low coupling between the transverse planes in order to achieve flat beams and produce high peak brilliance. Instead, operating at a high coupling has other advantages such as smaller emittance degradation due to intra-beam scattering, improved Touschek lifetime, and lower sensitivity to vibrations of the photon beam. Moreover, it has been suggested that a high coupling may enable achieving higher bunch currents thanks to sharing of the beam-induced wakefields between the transverse planes. We were able to take advantage of this effect to substantially increase the TMCI threshold at zero chromaticity and nearly double the single bunch current limit at high chromaticity at ESRF-EBS.
Paper: MOPS034
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS034
About: Received: 14 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
MOPS035
Space charge limit for light sources
668
With the adoption of multi-bend achromat lattices and the aim for diffraction limit, the state-of-the-art light sources are approaching a point where their emittance becomes so small that the effects of space charge can no longer be ignored. Space charge produces a significant betatron tune spread that affects many aspects of beam dynamics: single particle dynamics to collective beam stability. But most importantly, space charge imposes a fundamental limit to the ultimate beam brightness that can be achieved in a synchrotron light source. We demonstrate that the only way to increase the beam brightness and therefore the photon brilliance further is to opt for a higher beam energy.
Paper: MOPS035
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS035
About: Received: 06 May 2025 — Revised: 29 May 2025 — Accepted: 29 May 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
MOPS048
First options for an ESRF EBS upgrade lattice
708
A new lattice for the EBS is proposed as preliminary candidate for the next generation ESRF storage ring. This new optics would feature lower emittance, matched optics at all ID, transparency conditions for insertions and overall a net gain in brilliance coherence and flux. Due to the reduced dynamic aperture, on-axis injection with a low emittance beam would be a requirement in order to progress with these optics.
Paper: MOPS048
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS048
About: Received: 27 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
MOPS051
Light upgrade of the ESRF booster
716
The ESRF booster has been built more than 30 years ago as injector of the first ESRF storage ring and it is still used to inject in the EBS. Several components of the booster have been updated in the years and it is now operated off-energy and with emittance exchange at extraction, however the lattice has not been modified since the '90s. A project to reduce the equilibrium emittance and bunch length of the booster by exchanging 18 quadrupole magnets has been proposed. In this paper we present the beam dynamics studies in presence of errors and the expected gain in injection efficiency.
Paper: MOPS051
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS051
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
MOPS052
Overview of ESRF-EBS's four-year operation and strategy for further upgrade
719
The user operation of the Extremely Brilliant Source (EBS) since August 2020 has opened a new era of high energy fourth generation synchrotron radiation light sources. During the following four years of operation, the EBS accelerator has sustained user operation with high availability, reliability, and stability, and has continued to improve beam performance by reducing injection perturbations, increasing bunch/beam currents for different beam delivery modes, and consolidating the storage ring operation with a hot-swap power supply system, newly designed kicker ceramic chambers, etc. Sustainability has always been key to EBS operation and future upgrades. During user operation, measures on the RF system of the storage ring and HQPS operation have been implemented to save power consumption; in the near future, solid-state amplifiers and 4th harmonic RF system projects will ensure the sustainability of machine operation further. In addition, as a strategy for future upgrades of the EBS accelerator complex, injector upgrades are being considered, including the injection with a new linac, which can be further upgraded to inject full-energy beam into the storage ring.
Paper: MOPS052
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS052
About: Received: 29 May 2025 — Revised: 02 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
MOPS061
MAX 4U: an upgrade of the MAX IV 3 GeV ring
738
The MAX IV 3 GeV storage ring in Lund, Sweden, was the first implementation of a multibend achromat (MBA) lattice fourth-generation light source. Since it started delivery of light in 2016, three succeeding MBA-based rings and variants have come on-line: ESRF-EBS, Sirius and APS-U. Several others are being planned, designed, built or commissioned. All of these capitalize on the MBA concept and expand it to push the brightness and coherence performance even further. In order to continue to offer the Swedish and international scientific communities competitive tools beyond the end of this decade, MAX IV Laboratory launched in 2024 the conceptual design of MAX 4U , an upgrade of its 3 GeV storage ring aiming at an emittance below 100 pmrad. This performance boost is to be achieved through a minimum-interference upgrade in which localized interventions in selected subsystems and components are carefully chosen to provide the maximum performance increase with minimum cost and, equally important, minimum dark time for the MAX IV user community. This contribution describes the accelerator physics and engineering aspects of the MAX 4U conceptual design and presents the latest developments.
Paper: MOPS061
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS061
About: Received: 21 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
MOPS069
The Elettra 2.0 project status
754
After 31 years of serving the user community with excellent results, on July 2nd 2025 the removal of the Italian third generation synchrotron light source Elettra (www.elettra.eu) will start to be replaced by Elettra 2.0 a fourth-generation one. The project is in full development and, being a diffraction limited light source, Elettra 2.0 will provide ultra-high brilliance and coherence to the experiments while at the same time the machine is designed to provide very short pulses for time resolved experiments. The project status and its possibilities will be presented and discussed
Paper: MOPS069
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS069
About: Received: 24 Apr 2025 — Revised: 30 May 2025 — Accepted: 30 May 2025 — Issue date: 06 Jun 2025
MOPS074
The Novosibirsk fourth-generation light source SKIF development status
758
SKIF (Russian acronym for Siberian Circular Photon Source) – fourth-generation light source under construction in Novosibirsk. Natural emittance (at zero beam current and absent betatron coupling) of the SKIF is 72 pm at 3 GeV beam energy and 476 m circumference. Only two families of sextupoles provide horizontal and vertical dynamic apertures of 12 mm and 3.5 mm, respectively, and energy acceptance more than 5%. The flexibility of the lattice allows the beta functions to be changed in center of straight sections in a wide range from 0.5 m to 16 m, which opens up additional experimental possibilities for users. The paper presents status of development the SKIF project.
Paper: MOPS074
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS074
About: Received: 01 Jun 2025 — Revised: 02 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
MOPS079
Operational deployment of high brightness LHC beams in the SPS
764
Following the LHC Injector Upgrade programme (LIU) there has been a gradual ramp-up of the intensity of LHC beams in the CERN Super Proton Synchrotron (SPS). This was initially hampered by vacuum issues in several critical components, such as RF cavities and kicker magnets, requiring extensive scrubbing campaigns to condition these components. This paper reviews the current status of the high brightness LHC beams in the SPS, including commissioning evolution, aspects related to beam stability and beam optimization and the current brightness reach. An assessment of the operational readiness of these beams for the High Luminosity LHC era is also given.
Paper: MOPS079
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS079
About: Received: 26 May 2025 — Revised: 04 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
MOPS140
Conceptual study of multi-turn injection for SIS100 as a long-term perspective
815
The SIS100 synchrotron, currently under construction as part of the FAIR project, is set to play a pivotal role in advancing high-intensity ion beam research. Reaching the FAIR design intensities for low charge-state heavy ions, e.g. the reference ion U28+ will, however, be challenging due to limitations of the existing SIS18 synchrotron serving as injector to SIS100. In the long-term, the integration of a new linear accelerator capable of delivering high-intensity ion beams at energies up to 200 MeV/u would open the possibility of direct multi-turn injection (MTI) into SIS100, bypassing the SIS18. This paper investigates the MTI process for U28+ beams, aiming to accumulate up to 5x1E11 particles per cycle with high efficiency and minimal particle losses on the electrostatic septum. We present a theoretical analysis of horizontal-plane MTI, outline achievable beam performance, and discuss system requirements. Additionally, the proposed layout and parameters of the MTI equipment are detailed.
Paper: MOPS140
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS140
About: Received: 23 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 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
TUAD1
Progress in LINAC beam commissioning for high-intensity operations for J-PARC power upgrades
838
The Japan Proton Accelerator Research Complex (J-PARC) has achieved stable 1 MW operation test on its neutron target and is advancing toward higher power levels of 1.5 MW to support high-power MR operations and a second target station. This progression presents challenges, including increased intra-beam stripping (IBSt) of H⁻ ions, chop leakage from higher beam currents and emittance, low-energy beam loss due to halo formation, frontend fluctuations affecting beam transmission, and RF phase and amplitude fluctuations. To address these issues, a redesigned lattice mitigates IBSt, a new MEBT1 improves chopping and collimation, and machine learning-based compensation schemes manage frontend and RF fluctuations. Additionally, longitudinal and transverse matching schemes enhance beam quality, validated through benchmarked longitudinal measurements. Results from studies at 50 mA and 60 mA beam currents demonstrate significant progress in overcoming these challenges.
Paper: TUAD1
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUAD1
About: Received: 28 May 2025 — Revised: 30 May 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
TUBN2
RHIC polarized proton operation in Run24
878
The Relativistic Heavy Ion Collider (RHIC) Run 24 was 27 cryo weeks, operating with collisions at the STAR and sPHENIX detectors. The primary mode was polarized protons at 100 GeV, where there was 22 weeks of physics production. sPHENIX continued commissioning, becoming fully operational after 13 weeks and the addition of isobutane to their TPC gas mixture. STAR had a low luminosity run followed by twenty weeks of high luminosity and radially polarized beams. To reduce the beam-beam parameter and maximize the number of collisions within a small vertex region at sPHENIX, sPHENIX planned to operate with a crossing angle. For 8 weeks, collisions were only at sPHENIX until the beam-beam parameter was sufficiently low to support the additional collisions at STAR. A significant number of power dips earlier in the run greatly affected machine performance and reliability. At the maximum achieved performance, the luminosity was limited by four factors simultaneously: accelerating RF cavity intensity limit, intensity from the injectors, losses at rebucketing, and dynamic aperture. Despite these difficulties, sPHENIX and STAR were able to collect sufficient data commensurate with their goals.
Paper: TUBN2
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUBN2
About: Received: 29 May 2025 — Revised: 31 May 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
TUCD2
Commissioning of the Advanced Photon Source upgrade - the first swap-out injection-based synchrotron light source
898
The Advanced Photon Source (APS) recently completed a transformative upgrade, replacing its 25-year-old storage ring with a state-of-the-art hybrid seven-bend achromat lattice with six additional reverse bends. The new design features a low natural emittance of 42 pm-rad, enabling productions of X-rays up to 500 times brighter than the original APS. The upgrade introduced a pioneering swap-out injection scheme, replacing entire depleted bunches rather than topping them up. This approach enables on-axis injection to accommodate for the reduced dynamic aperture resulting from strong focusing. The paper describes the commissioning process, operating experience with swap-out injection, and gives performance parameters of new systems such as the bunch-lengthening cavity.
Paper: TUCD2
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUCD2
About: Received: 27 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 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
TUPB022
Reduction of beam loss at the fast extraction section in J-PARC MR
982
At J-PARC MR, proton beams are supplied to the neutrino facility via fast extraction (FX). The beam power, which was 500 kW in 2021, reached 800 kW by June 2024, with further upgrades planned. This increase in power has led to a rise in beam loss in the FX section, necessitating countermeasures. Residual doses are high at positions where the FX beam orbit closely approaches the aperture, and the effectiveness of beam loss countermeasures is evaluated by changes in residual dose. By June 2024, residual doses were successfully reduced through adjustments to the beam optics. For further reduction of beam loss, in July 2024, the aperture was expanded at the most upstream position where the beam orbit is in close proximity to the aperture. This report discusses the achievements during subsequent FX operations and outlines plans for further improvements.
Paper: TUPB022
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB022
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
TUPB026
Research and development study on nanobeam formation using laser-cooled ions for high-precision single-ion irradiation
997
To realize high-precision single-ion irradiation or implantation, we have proposed a nanobeam formation scheme where single cold ions selectively separated from a two-component Coulomb crystal in a linear Paul trap (LPT) are accelerated to 100 keV and focused on the nanometer scale using electrostatic bipotential lenses. The entire process of laser cooling of trapped ions in the LPT, ion-selective ejection from the LPT, acceleration, and focusing in the lens system is investigated by detailed multiparticle tracking simulations to show the feasibility of ultralow-emittance nanobeam formation and ion focusing properties. According to the simulation results, the fabrication and commissioning of such a single-ion irradiation system are ongoing at Takasaki Institute for Advanced Quantum Science, National Institutes for Quantum Science and Technology toward the application of research and development of quantum materials and devices. We will discuss the simulation results on the behavior of cold ions in the irradiation system and report the latest status of the system development including preliminary experimental results.
Paper: TUPB026
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB026
About: Received: 26 May 2025 — Revised: 31 May 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
TUPM012
Stable generation of high-quality beam by 3-GeV low-emittance linear accelerator in NanoTerasu
1166
The construction of a low-emittance 3-GeV linear accelerator as an injector system of a new high-brilliance synchrotron radiation facility “NanoTerasu” was completed in January 2023. After beam commissioning of the accelerator complex for several months, the synchrotron radiation for user experiment was provided in April 2024 as planned [*]. The 3-GeV compact linear accelerator consists of 40-MeV injector system and C-band accelerator. The electron beam with a bunch charge of more than 0.5 nC and normalized emittance of less than 2 mm mrad is generated from an electron RF gun system with a gridded thermionic cathode at a “transparent” grid condition [**]. In the 40-MeV injector system, the bunched beam with a bunch length of 5 ps and normalized emittance of less than 10 mm mrad is generated. In usual operation, the bunched beam is accelerated up to 3 GeV and injected stably into the storage ring. In this presentation, we report on the establishment of beam adjustment by tuning RF amplitude and phase. We also report on the beam performance obtained, including beam stability, and comparing the design beam envelope and measured beam optics in the linear accelerator.
Paper: TUPM012
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM012
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 04 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
TUPM026
Advanced beam tuning and beam measurements techniques in the CLEAR facility
1193
The CLEAR (CERN Linear Electron Accelerator for Research) facility delivers to a wide user community a 200 MeV electron beam with highly flexible parameters. Running conditions range from single-bunch to multi-bunch operation, with bunch charges from 10 pC to 1 nC, bunch durations from 100 fs to tens of ps, and includes tunable momentum (30 MeV/c to 220 MeV/c). Such a variety of beam conditions poses a challenge to the beam instrumentation and to the beam measurements and tuning techniques, even more so given that quite often a rapid switch from one set of conditions to a very different one is required. In this paper we present several examples of the techniques developed in CLEAR for this purpose and discuss their advantages and limitations. Examples include emittance measurements and phase space reconstruction procedures by quadrupole scans and beam based alignment methods.
Paper: TUPM026
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM026
About: Received: 28 May 2025 — Revised: 04 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
TUPM053
Design of a resonant slow extraction from the planned DESY IV booster synchrotron
1243
The planned upgrade of the synchrotron light source at DESY, Hamburg will include an upgrade of the booster synchrotron. We discuss the considerations for the design of a slow resonant extraction from this future machine. The implementation of a bent crystal as a potential septum shadower and/or as a septumless option is considered.
Paper: TUPM053
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM053
About: Received: 26 May 2025 — Revised: 01 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
TUPM056
Beam control and characterization of the new SLS 2.0 booster-to-ring transfer line
1251
Off-axis top-up injection into 4th generation storage ring light sources is complicated due to the transverse acceptance, which is typically in the order of a few millimeters. Therefore, the characteristics and control of the incoming beam from the transfer line plays an important role in achieving successful injection. SLS 2.0, the storage ring upgrade of the Swiss Light Source, is among the facilities where precise knowledge and control of the injected beam is important, particularly due to the usage of emittance exchange in the booster synchrotron. Here we highlight the most important design aspects of the new SLS 2.0 booster-to-ring transfer line, including the nondispersive section for beam characterization and the double-corrector configuration allowing injection position and angle control. Furthermore, we present the first experience with quadrupole scans and stabilization of the injected beam.
Paper: TUPM056
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM056
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
TUPM065
Nb3Sn superconducting multipole wiggler as a vertically polarized hard X-ray source
1281
Vertically polarized superconducting wigglers enable unique hard X-ray experiments based on horizontal optical setups. However, their implementation in modern low-emittance storage rings has been limited due to significant emittance growth. We present a vertically polarized superconducting multipole wiggler designed to reduce the impact on beam emittance. By limiting the magnetic field to 2-3 T and shortening the period length using Nb3Sn wires with higher critical current density compared to conventional NbTi, the beam orbit amplitude and the resultant emittance growth are reduced. As a case study for the future light source project at KEK, PF-HLS (Photon Factory Hybrid Light Source), we discuss a design based on vertical circular winding coils with a sub-100 millimeter period length and a sub-100 micrometer orbit amplitude, as well as its influence on beam emittance.
Paper: TUPM065
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM065
About: Received: 28 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
TUPM094
Simulations of transverse dynamics in a laser-plasma accelerator
1350
Laser Wakefield Accelerators (LWFA) offer a promising solution for producing high-energy electron beams in compact setups. Beyond obtaining the required energy, the beam quality (emittance, energy spread, intensity) must also be optimized for LWFA to be considered an alternative to conventional accelerators. Achieving precise control of the transverse beam dynamics is one of the key challenges. This article thoroughly studies the physics governing the evolution of emittance and Twiss parameters within the plasma stage, on the density plateau, and in the up-ramp and down-ramp connections to conventional transport lines. Analytical and numerical analysis will be conducted using a toy model made of special quadrupoles, allowing numerical calculations to be sped up to a few seconds/minutes. Matching between plasma and transport lines will be extensively studied, clearly showing the dependence on initial conditions, and recommendations for the best realistic configurations will be provided*.
Paper: TUPM094
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM094
About: Received: 03 Jun 2025 — Revised: 03 Jun 2025 — Accepted: 03 Jun 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
TUPS019
Beam dynamics optimization in high-brightness Photo Injector with various photocathode laser pulse shapes
1428
At PITZ, a comprehensive study is conducted to analyze the factors influencing emittance growth in the European XFEL (EuXFEL) continuous wave (CW) setup. Emittance growth due to space charge effects can be mitigated using advanced photocathode laser pulse shapes. To optimize beam quality, multiobjective optimization studies using ASTRA are performed, focusing not only on minimizing emittance but also on maximizing beam brightness for various laser temporal profiles and dura-tions. The optimization is initially carried out for the CW injector section planned for EuXFEL. The optimized cases are then further tracked through start-to-end (S2E) simulations to evaluate their behavior in the compression stages of EuXFEL. A comparative analysis of gaussian, flattop, ellipsoidal, and inverted parabolic laser profiles is presented, assessing their efficiency not only in terms of emittance but also in 4D and 6D brightness. Finally, the results of the optimized photoinjector setup and the beam properties after the final bunch compression will be presented.
Paper: TUPS019
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS019
About: Received: 06 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
TUPS026
Magnetic cycle optimisation in the CERN PS booster
1438
The PS Booster is the first synchrotron in the CERN proton accelerator complex, which delivers both high-brightness and high-intensity beams. Injection to the Booster is at a kinetic energy of 160 MeV, therefore space charge is a main limiting factors for beam quality. Maximising the longitudinal emittance and adding a second, and sometimes third, RF harmonic are measures to decrease the line density and so reduce the effect of space charge. Nonetheless, beam loss and transverse emittance growth are still unavoidable at low energy. Recent studies have been focused on the possibility of adapting the magnetic cycle to further reduce the impact of space charge. With a faster ramp, the time spent in a high space charge regime is reduced but the available RF voltage limits the bucket area. Alternatively, with a slower acceleration the RF bucket area and longitudinal emittance can be increased, which will reduce the magnitude of the space charge detuning, but more time will be spent at low energy. This contribution explores the effects of different magnetic cycles on the beam and the possibility of further optimising the booster acceleration.
Paper: TUPS026
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS026
About: Received: 19 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
TUPS039
Current status of beam commissioning at the Frankfurt Neutron Source
1485
The Frankfurt Neutron Source FRANZ will be a compact accelerator driven neutron source utilizing the 7Li(p,n)7Be reaction with a 2 MeV proton beam. The 700 keV RFQ has been sucessfully commissioned with a 10 mA proton beam. Conditioning of the subsequent IH-type cavity has been performed up to 10 kW. We also report on RFQ emittance measurements performed with a slit grid emittance device. In addition, a fast faraday cup (FFC) was used for bunch shape measurements behind the RFQ.
Paper: TUPS039
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS039
About: Received: 26 May 2025 — Revised: 02 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
TUPS130
Compressed ultrashort pulse injector demonstrator
1594
High brightness electron beams have a wide range of applications ranging from accelerator-based light sources to ultrafast electron diffraction and microscopy. High accelerating gradient photoinjector is an important tool to generate brighter electron beams. However, high gradient photoinjector suffers issues from material breakdown due to extremely high surface electric fields. One possible path to simultaneously achieve high gradient and suppress breakdowns is to reduce the rf pulse duration fed into the photoinjector. Such an approach was recently demonstrated at the Argonne Wakefield Accelerator (AWA) facility where they commissioned an X-band photoinjector at 400 MV/m cathode field without significant breakdown rates. SLAC National Accelerator Laboratory recently developed rf pulse compression technology optimized for short pulses up to 500MW. We propose to develop an X-band photoinjector which can utilize these ultrashort rf pulses to produce surface fields at 500 MV/m or higher at the cathode. This presentation focuses on the design of the X-band photoinjector.
Paper: TUPS130
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS130
About: Received: 24 May 2025 — Revised: 31 May 2025 — Accepted: 01 Jun 2025 — Issue date: 06 Jun 2025
WECN1
SLS 2.0 storage ring commissioning
1679
The SLS consists of a 100MeV linac, a 2.7GeV booster synchrotron with 9nm horizontal emittance and the storage ring (SR). The old 12-TBA SR with 5nm horizontal emittance operating at 2.4GeV was turned off in 09/2023 after 22 years of successful user operation. In course of the SLS 2.0 upgrade project the 288m circumference SR has been replaced by a 2.7GeV 12-fold 7-bend achromat lattice with a considerably reduced horizontal emittance of 150pm, while keeping the injector complex mostly unchanged. After recommissioning of the injector chain at the end of 2024 SR commissioning starts in January 2025 with some challenges ahead. A reverse bend design has been implemented to achieve the lowest possible emittance with the given small footprint of the SR leading to a very dense magnet arrangement. All bending and combined function magnets which largely determine the novel optics are permanent magnets which will guide the beam through NEG coated vacuum tubes with an aperture of only 18mm. Due to excellent beam diagnostics and optics adjustment capabilities combined with an advanced remote girder alignment system we expect to achieve the performance goals of the storage ring by mid 2025.
Paper: WECN1
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WECN1
About: Received: 28 May 2025 — Revised: 30 May 2025 — Accepted: 30 May 2025 — Issue date: 06 Jun 2025
WEPB047
Insertion devices for the ultralow emittance storage ring ALBA II
1796
The ALBA synchrotron light source is undergoing a transformative upgrade to become a state-of-the-art fourth-generation facility, known as ALBA II. This upgrade will reduce the electron beam emittance to approximately 200 pm·rad, achieving a twentyfold improvement over the current performance. A key goal of the project is to maintain the existing source points for the insertion device beamlines; in fact, most of the currently installed devices will be kept after the upgrade. Nevertheless, selected insertion devices will be replaced to fully exploit the enhanced capabilities of the upgraded electron beam. Additionally, two available straight sections will be utilized to support the development of ultra-long beamlines exceeding 250 meters, enabling advanced nano-probing and coherence-based experimental techniques. This paper outlines the strategic plans for the new insertion devices, detailing the design criteria and the constraints guiding their development.
Paper: WEPB047
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB047
About: Received: 27 May 2025 — Revised: 30 May 2025 — Accepted: 31 May 2025 — Issue date: 06 Jun 2025
WEPM015
Optics function determination using luminosity data
1941
Determining the betatronic waist shift and the $\beta^*$ at the interaction points through K-modulation in the Large Hadron Collider presents considerable challenges. This paper introduces a novel method for the measurement of these quantities, based on luminosity measurements and the van der Meer technique for reconstructing transverse bunch profiles. The strategy involves colliding multiple bunches with distinct emittances, performing emittance scans, and subsequently shifting the collision point along the longitudinal plane via RF cogging. This shows promising potential to reduce uncertainties in the optics parameters at the interaction point and to obtain measurements of the absolute beam emittance. The first measurement using this technique was carried out at the Large Hadron Collider, with the analysis and findings discussed in detail.
Paper: WEPM015
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM015
About: Received: 23 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 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
WEPM024
BESSY III intra-beam scattering and touschek lifetime calculations
1965
The 4th generation synchrotron light source, BESSY III, is expected to enable high-impact applications for users in life science, material science, energy and catalysis materials, and more. Currently in its Conceptual Design Report (CDR) phase, the feasibility of BESSY III's ambitious parameter range necessitates a thorough assessment of "collective effects". These phenomena can either compromise beam stability or degrade beam quality, potentially hindering the expected performance. In this work, we present recent estimations of the Intra Beam Scattering (IBS) and Touschek lifetime for the BESSY III lattice. The IBS leads to an increase in longitudinal and transverse emittances, it is described through the IBS growth rates and equilibrium emittances. Both quantities were computed with the ibsEmittance module from elegant and a newly implemented module in Xsuite. The Touschek effect induces beam losses along the storage ring resulting in a shorter beam lifetime. Its effect was computed using pyAT. Finally, the impact of different emittance coupling factors is studied to mitigate both effects, laying the first stone for future studies with higher-harmonic cavities.
Paper: WEPM024
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM024
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
WEPM029
Trajectory design for passing through solenoid magnet fringe field and method for adjusting its strongly X-Y coupled phase space for three-dimensional spiral beam injection
1977
A three-dimensional spiral beam injection scheme* has been developed to realize very precise measurement of the muon spin precession frequency in the level of sub-ppm. A 300MeV/c muon beam is injected into a precisely adjusted storage magnet of sub-ppm uniformity by applying medical MRI magnet technologies for J-PARC muon g-2/EDM experiment. A strongly X-Y coupled beam is required to deliver beam into the storage volume via strong radial fringe field volume of solenoid magnet followed by beam injection channel through iron yoke**. A dedicated design work of reference trajectory and beam phase space has been made in this injection section. In this presentation, we show evaluated the tolerance for the accuracy of the reference trajectory and the orbital position dependence of the required X-Y coupling parameters and discuss the required accuracy of the transport line placed upstream of the beam-line which includes eight rotating quadrupoles on the 10m of beam transport line**. Additionally, a pair of dedicated magnets called active shield steering magnet will be set at the entrance and the exit of the beam channel to perform orbital correction of the reference trajectory.
Paper: WEPM029
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM029
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
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
WEPM044
Analysis of losses and emittance growth in the 2024 LHC run and correlation with Dynamic Aperture
2026
This paper presents observations collected during the LHC operation with proton beams in 2024. In particular, a systematic analysis of the beam and machine parameters along the run reveals that the emittance evolution at the LHC injection plateau and during collisions cannot be fully explained by Intra-Beam scattering, synchrotron radiation and electron cloud effects, thus indicating that some beam dynamics effects are missing in the models. During the collapse of the separation bumps, a significant drop in beam lifetime is observed due to the reduction of Dynamic Aperture as the separation reduces and the machine enters into a beam-beam dominated regime. The correlation of beam lifetime in operation and Dynamic Aperture in simulations is demonstrated. Furthermore, a strong correlation is identified between this lifetime reduction and the population of non-Gaussian tails in the transverse beam profiles. The paper also includes the observation of high-frequency power supply ripple in the beam spectrum.
Paper: WEPM044
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM044
About: Received: 29 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
WEPM045
Luminosity modeling of the LHC operation and performance projections for HL-LHC
2030
The LHC luminosity model is a powerful tool for studying the evolution of beam and machine parameters during the LHC operation. The model includes important effects that are present in LHC operation such as Intra-Beam Scattering, synchrotron radiation and burn-off. By comparing model predictions with experimental data, the presence of additional emittance blow-up and intensity loss mechanisms can be identified and then further studied. Using this model for comparing different configurations such as optics, filling schemes and beam types, allows identifying the best strategy to be adopted in operation to maximize integrated luminosity. In this contribution, we show the benchmarking of this model with data from the presently ongoing LHC Run 3, and its application to predicting the integrated luminosity for its future High-Luminosity LHC upgrade.
Paper: WEPM045
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM045
About: Received: 29 May 2025 — Revised: 01 Jun 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
WEPM063
Symmetric double-double bend lattice for a potential EUV diffraction limited upgrade of the HLS
2070
NSRL recently proposed a future plan to further upgrade the HLS to an EUV diffraction-limited storage ring, named HLS-III. In this paper, a symmetric double-double bend lattice with long and mid-straight sections is studied as a highly promising design for the HLS-III storage ring. The design achieves an ultra-low natural emittance of 2.82 nm·rad at 800 MeV, while maintaining the current eight straight sections but with significantly reduced beta functions in these straights. By minimizing the fluctuation of resonance driving terms, the nonlinear dynamics optimization yields a large horizontal dynamic aperture of about 40 mm. Additionally, error and intra-beam scattering effects are evaluated.
Paper: WEPM063
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM063
About: Received: 08 Apr 2025 — Revised: 31 May 2025 — Accepted: 02 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
WEPM082
Cavity loops Influence on the single-bunch Instability thresholds of the CERN PS Booster
2125
The CERN Proton Synchrotron Booster (PSB) delivers a wide variety of high-intensity and high-brightness proton beams to several destinations, including operations at the Large Hadron Collider (LHC) and various fixed-target experiments. Following the Long Shutdown 2 (LS2) upgrades, discrepancies between beam measurements and macro-particle simulations were observed, highlighting the need for a deeper understanding of the longitudinal impedance and related effects in the PSB. To address this, longitudinal single-bunch instability studies have been conducted to evaluate the impedance model through the intensity and energy thresholds across different radio-frequency configurations. This contribution presents experimental results that explore instability mechanisms and the effect of the beam loading compensation feedback system. These results are used to benchmark a new cavity loop simulation, which enables more detailed studies of the accelerator impedance.
Paper: WEPM082
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM082
About: Received: 27 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
WEPM105
Progress on the 5BA lattice studies for ALBA-II
2183
ALBA-II is progressing in the definition of an upgrade lattice that meets the requirements of the beamlines and perform well in terms of dynamics aperture and lifetime. The last changes were focused on further decreasing both the emittance (200 pm*rad) and the beta functions at the straight sections (around 2 m) for the improvement of the beamlines performances. The efforts to guarantee a good performance of such a lattice have been focused on the improvement of a horizontal dynamic aperture larger than 6 mm (needed for off-axis injection) and of a lifetime around 10 hours. Octupole magnets next to each sextupole have been introduced to correct the large tune shift with amplitude that is limiting the dynamic aperture. Simulations of the lattice commissioning and robustness with magnet, alignment and instrumentation errors are being carried out. The efficiency of the off-axis injection process including both lattice and pulsed elements errors is also under evaluation.
Paper: WEPM105
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM105
About: Received: 27 May 2025 — Revised: 31 May 2025 — Accepted: 31 May 2025 — Issue date: 06 Jun 2025
WEPS002
Performance of the diode stack with resistors to suppress beam instability at the J-PARC RCS
2201
The main source of beam instability in the J-PARC 3-GeV RCS is the impedance of the eight installed kickers. This arises because one end of each kicker magnet is shorted while the other end is left open during beam acceleration. The shorted-end configuration provides the benefit of power savings during beam extraction from the RCS. However, it also excites beam instability. To retain the energy-saving benefit while suppressing beam instability, we developed a diode stack with resistors and inserted it at the open ends of four kickers. This configuration effectively suppresses beam instability for smaller-emittance beams, which are delivered to the MR at J-PARC.
Paper: WEPS002
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS002
About: Received: 26 May 2025 — Revised: 31 May 2025 — Accepted: 31 May 2025 — Issue date: 06 Jun 2025
WEPS009
Interaction of intrabeam scattering, longitudinal wakefield, and a passive harmonic RF cavity in SOLEIL II
2217
Synchrotron light sources worldwide are transforming into next-generation facilities with ultralow transverse emittances at the diffraction limits. With these parameters, intrabeam scattering (IBS) becomes significant and can spoil the light quality by increasing emittance. A harmonic cavity can be installed to mitigate this effect by increasing the bunch length. Another way to reduce the impact of IBS is to operate with the full transverse coupling. This contribution considers the IBS effect on SOLEIL II performance with an up-to-date impedance model, passive harmonic cavity, different insertion device gap configurations (open, close), and full transverse coupling for all foreseen operation modes. The combined effect of IBS and microwave instability (MWI) on the energy spread is reported. It is demonstrated that the contribution of IBS to energy spread increase is as important as that of MWI.
Paper: WEPS009
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS009
About: Received: 24 Apr 2025 — Revised: 04 Jun 2025 — Accepted: 04 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
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
WEPS016
Experimental investigation of longitudinal scraping of H- bunches via photo-detachment
2236
Longitudinal emittance growth is a significant challenge in RF linacs, especially for poorly bunched beams. This stems from particles occupying outer synchrotron oscillation orbits in the LBET, causing unwanted bunch-bunch interactions and degraded beam quality. To address this, we proposed using temporally spaced laser pulses to selectively photo-detach electrons from the longitudinal head and tail regions of H- ion bunches. This approach aims to reduce particle density in extreme orbits, enhancing beam uniformity and limiting emittance growth. Our experiments employed Fermilab's 'LaserNotcher' system at the font end of the linac, delivering 1.6 MW peak power with sub-nanosecond precision. By neutralizing the first and last half-nanosecond of several H- bunches, we measured their propagation injection into the booster. Measurements of pulse width, average height, and temporal spacing over booster cycles were compared between the scraped and unscraped bunches. Statistical analysis evaluated the results’ significance, highlighting the feasibility of laser-based scraping for future linac designs to achieve higher beam energies with improved emittance control.
Paper: WEPS016
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS016
About: Received: 03 Jun 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
WEPS023
Study for limiting factors in transverse wiggler-based arbitrary correlation generation
2255
Recently proposed transverse wiggler is an intriguing tool for imparting designed correlations in phase space. While several simulations have demonstrated its feasibility, the method using the transverse wiggler has several concerns need to be addressed. Beam evolution along the wiggler can introduce errors in the designed correlation. Wiggler fields have strong vertical position dependence, which can introduce unwanted horizontal and vertical couplings. The transverse wiggler generates both horizontal and vertical sinusoidal fields, which can significantly degrade the beam quality. Additionally, its applicability to heavy particles remains uncertain. We will present results from a preliminary study aimed at addressing these concerns.
Paper: WEPS023
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS023
About: Received: 28 May 2025 — Revised: 30 May 2025 — Accepted: 01 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
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
WEPS091
Intrabeam scattering in SRF "SKIF" storage ring
2369
SKIF (Russian acronym for Siberian Circular Photon Source) – is a new fourth generation synchrotron light source under construction in Novosibirsk, Russian Federation. One of the most important characteristics of the synchrotron radiation source SRF "SKIF", which in turn determines its brightness, is the ultra-low emittance of the electron beam, which depends on the operating regime and parameters of the storage ring: the intensity of the electron beam, the insertion devices parameters, the coupling coefficient of linear betatron oscillations, the elongation of the bunches, etc. Intrabeam scattering (IBS) is a collective effect that causes bunch volume inflation and brightness decrease for high intensity beams. Described in this work are the results of study of IBS impact on beam emittance, energy spread, Touschek lifetime and geometrical brightness for different operating regimes of the SRF “SKIF” storage ring.
Paper: WEPS091
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS091
About: Received: 29 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
WEPS108
Studies of resonances limiting the high-brightness LHC beams in the SPS
2392
Space charge effects in combination with betatron resonances limit the performance of high-brightness LHC beams in the CERN Super Proton Synchrotron (SPS). Here we report on experimental studies performed with single-bunch proton beams, monitoring transverse emittance evolution and particle losses while performing tune scans across the horizontal and vertical planes. Two significant resonances were identified: a coupled resonance leading to emittance growth in the horizontal plane and a corresponding emittance decrease in the vertical plane, and another coupled resonance directly associated with particle losses. The resonances identified in these studies could explain the limitations of the beam brightness encountered with the multi-bunch LHC-type beams in the SPS, thus providing valuable insights for the optimization of the high-intensity beams performance.
Paper: WEPS108
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS108
About: Received: 27 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
WEPS110
An updated HL-LHC halo population model based on recent experimental measurements
2396
The transverse beam halo population in the Large Hadron Collider (LHC) has been found to carry a significant fraction of the total stored beam energy, potentially reaching several percent. With the anticipated increase in beam brightness for the High Luminosity LHC (HL-LHC), this poses an increasing risk to machine safety, particularly during abrupt orbit shifts or critical component failures. A comprehensive understanding and an accurate modelling of the transverse beam halo are crucial for simulations of beam losses around the ring as a consequence of such failure scenarios in the HL-LHC era. Various models, including Gaussian, double-Gaussian, and q-Gaussian distributions, have been used to describe the LHC beam halos for fitting the measured distributions. This paper provides an in-depth analysis of halo modelling based on collimator scraping measurements from the LHC operational Run 2 and Run 3, and evaluates the accuracy and representativeness of these different distribution models.
Paper: WEPS110
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS110
About: Received: 27 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 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
THPM035
MENT algorithm for transverse phase space reconstruction at SIRIUS
2708
The injector system of SIRIUS, the brazilian 4th generation synchrotron light source, currently operates with non-ideal injection efficiencies, which may impose limits to future top-up operation modes. Within this context, diagnostic techniques to access beam quality in the injector are essential tools for optimizations. In this work, the MENT algorithm was implemented for the reconstruction of two-dimensional probability densities, aiming to determine the electron density in the transverse phase space at the end of the LINAC. The implemented method has been validated through simulations of several distributions, demonstrating its reliability, and applied to analyze preliminary experimental results.
Paper: THPM035
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPM035
About: Received: 28 May 2025 — Revised: 01 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
THPM043
Performance assessment of profile monitors at CERN’s LHC using systematic analysis tools
2727
In this paper, we investigate statistical and systematic tools to establish performance benchmarks for future beam profile measurement tools, using extensive data from both prototype and legacy Beam Wire Scanners and the Beam Synchrotron Radiation Telescope at the LHC. We detail direct and comparative analyses, including variability in beam size measurements, positioning accuracy, and profile shape fidelity relative to theoretical models, with particular focus on non-Gaussian tails influenced by the beam halo effect. This work establishes a foundation for systematic performance assessment applicable to both current and next-generation profile measurement tools.
Paper: THPM043
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPM043
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
THPM072
The online emittance monitor at Taiwan Photon Source
2789
This study summarizes the X-ray pinhole camera results from two recently constructed diagnostic beamlines. We provide updated emittance and energy spread measurements for the TPS storage ring and implement online measurements for routine operational monitoring.
Paper: THPM072
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPM072
About: Received: 19 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 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
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