quadrupole
MOPB014
Relativistic strophotron free electron laser
95
The scheme with quadrupole lenses is presented for realization relativistic strophotron type Free electron laser. Equations of motion are solved and trajectories are found. It is shown, that movement of electrons in presented scheme is stable in both transverse directions.
Paper: MOPB014
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB014
About: Received: 24 Apr 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPB033
A novel design of a magnetic chicane with positive R56
130
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: 10 Jul 2025
MOPB053
Preliminary beta beating correction at the Canadian Light Source
169
The Canadian Light Source does not currently correct beta beating driven by its insertions devices. However, it has been known for some time that insertion device correlated vertical beam size changes can cause large reduction in flux at the VESPERS beamline. In this work we discuss our preliminary explorations to control the vertical beam size and correct beta beating.
Paper: MOPB053
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB053
About: Received: 27 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPB066
Compensation of an elliptically polarizing undulator in the HLS-II storage ring
201
The insertion devices (IDs) can severely affect the beam dynamics of a storage ring. Recently, a new elliptically polarizing undulator(EPU) is installed in the Hefei Light Source II (HLS-II) storage ring. The effects of this EPU can be modeled using the kick map method. In this paper, we present the kick map of the EPU with vertical mode and how it affects the beam dynamics. Since the HLS-II storage ring is compact, only four quadrupoles in the same straight section can be used to compensated the ID effect. The compensation result is also reported in this paper.
Paper: MOPB066
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB066
About: Received: 21 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
MOPB071
Simulation study on fast beam-based alignment for commissioning of light sources
204
Beam based alignment (BBA) plays an important role in the commissioning of the light sources. To speed up the BBA, a BBA method using AC excitation, called fast BBA (FBBA), has been proposed and is tested in several existing light sources. In the FBBA, the beam orbit is sinusoidally modulated at around 10Hz by AC correctors, and the change in the beam response when a target quadrupole magnet strength is changed is measured using fast beam position monitors (BPM) at about 10kHz. To apply FBBA to light source commissioning, a simulation study of FBBA using random variables as response functions was performed to calculate the optimal corrector strength and variation of the strength of a quadrupole as a function of the BPM noise. We also improved the FBBA and found that a new FBBA scheme using two AC correctors of different frequencies separated by 1/2π betatron phase for one plane (horizontal or vertical) can suppress the BPM offset error by up to 10.
Paper: MOPB071
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB071
About: Received: 28 May 2025 — Revised: 01 Jun 2025 — Accepted: 01 Jun 2025 — Issue date: 10 Jul 2025
MOPB072
Magnet crosstalk in highly-compact light-source storage ring
208
Electron storage rings based on multi-bend achromat (MBA) lattice can achieve very low natural emittances. Several fourth generation light sources have been built and operating, the natural emittances of which are a few 100 pm or even lower than 100 pm, providing high brightness photon beams to users. Since the lattice of MBA storage ring tends to be highly compact, the field of a magnet may be affected by the neighboring magnets. This effect turned out to be significant in the new Swiss Light Source storage ring with 7-BA lattice during its design study: the integral fields of magnets are altered by a few percent due to the magnet cross talk at locations, which is an order of magnitude larger than the field precision typically required. We present how we managed to reproduce the design magnetic fields and optics including the cross talk effects
Paper: MOPB072
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB072
About: Received: 24 May 2025 — Revised: 30 May 2025 — Accepted: 31 May 2025 — Issue date: 10 Jul 2025
MOPB100
An alternative lattice for the ZIPS storage ring
239
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: 10 Jul 2025
MOPB101
Bayesian optimization for the local bump injection in the HLS-II storage ring
242
Currently, a conventional local bump injection system with four pulsed dipole kicker magnets is adopted in the Hefei Light Source II (HLS-II) storage ring to achieve topoff operation. Due to the multipole magnets located between the kickers in the injection section, the local bump injection presents technical challenges in forming a perfect closed bump, which causes oscillation to the stored beam. In order to reduce the injection disturbance on the stored beam, the Bayesian Optimization (BO) method is employed to determine the kick angles of the four bump kickers.
Paper: MOPB101
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB101
About: Received: 09 Apr 2025 — Revised: 31 May 2025 — Accepted: 01 Jun 2025 — Issue date: 10 Jul 2025
MOPM009
Optics tuning of the FCC-ee
282
The Future Circular Collider, FCC-ee, is a proposed next generation electron-positron collider aiming to provide large luminosities at beam energies from 45.6 up to 182.5 GeV. This collider faces a major challenge to deliver the design performance in the presence of realistic lattice errors. A commissioning strategy has been developed including dedicated optics designs, efficient beam-based alignment and optics corrections based on refined optics measurements. First specifications on main magnets, corrector circuits, and instrumentation have also been investigated. A summary of all these aspects is presented in this paper.
Paper: MOPM009
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM009
About: Received: 28 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPM010
Emittance tuning of the FCC-ee high energy booster ring
286
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: 10 Jul 2025
MOPM018
Energy sensitivity of the High Luminosity LHC optics at the end of the Beta* squeeze
318
During 2022 and 2023 LHC optics commissioning, it was observed that at low-beta* small changes in the beam-energy could generate substantial perturbations of the linear beam optics, requiring re-commissioning of local corrections in the experimental insertions. This issue may become even more significant at the very low beta* anticipated for operation in the High Luminosity LHC (HL-LHC). Furthermore, energy drifts, for example due to the terrestrial tides, have generally been ignored during LHC optics commissioning, with no regular corrections applied during the duration of a specific measurement campaign. This paper examines the anticipated sensitivity of HL-LHC optics corrections to energy errors at end of the beta* squeeze.
Paper: MOPM018
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM018
About: Received: 27 May 2025 — Revised: 30 May 2025 — Accepted: 02 Jun 2025 — Issue date: 10 Jul 2025
MOPM027
Impact of ground motion on FCC-ee performance
354
The Future Circular Collider for electron-positron collisions (FCC-ee) is a proposed next-generation particle accelerator aimed at achieving high luminosity and precision for fundamental particle physics experiments. Its performance is sensitive to environmental factors such as ground motion, which can induce vibrations and misalignments in critical accelerator components. This paper presents a detailed study on the impact of ground motion on FCC-ee performance, with a focus on beam stability, alignment tolerances, and the complex interplay between ground motion and operational parameters. Using advanced simulations and analytical modeling, we evaluate the FCC-ee's sensitivity to various ground motion scenarios, ranging from localized, uncorrelated disturbances to correlated plane waves, and analyze their effects on the beam optics, orbit distortions, and overall beam dynamics. The findings provide valuable insights into the design and operational strategies required to mitigate ground motion effects, guiding future research and engineering efforts to ensure the successful realization of the FCC-ee project.
Paper: MOPM027
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM027
About: Received: 27 May 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
MOPM029
Progress on the 10 TeV center-of-mass energy muon collider
362
A 10 TeV center-of-mass muon collider could serve as a next-generation high-energy lepton collider with substantial physics potential while offering a more compact footprint than other proposed machines. However, this collider presents unique challenges, largely due to the short lifetime of muons and their decay products. Specifically, the collider ring requires specialized designs to protect the magnets and detectors while ensuring negligible neutrino radiation at Earth's surface. The high required luminosity also imposes stringent constraints, including very small beta functions at the interaction points that lead to strong chromatic effects. To meet these challenges, high-field combined-function magnets are used to create a compact layout with minimal straight sections. Flexible momentum compaction arc cells are used to maintain short bunch lengths and local chromatic correction sections to address the chromatic aberrations from the interaction regions. This work presents recent advancements in the 10 TeV muon collider ring, including interaction region improvements to reduce beam-induced background and a study that investigates the impact of $\beta^*$ on the dynamic and momentum acceptance.
Paper: MOPM029
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM029
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPM031
Tapering schemes for FCCee
370
The electron-positron Future Circular Collider (FCC-ee) is designed to operate at four beam energies, from 45.6 GeV to 182.5 GeV. At such energy levels, the circulating beam loses a significant fraction of its energy via synchrotron radiation. As a single RF insertion is foreseen in the ring, large closed-orbit shifts featuring a typical sawtooth pattern and optics distortions are induced. This in turn leads to a significant reduction of the dynamic aperture if no mitigation is implemented. The solution is to adapt the fields of the magnets to the local beam energy which is referred to as "tapering". For practical reasons, this field adjustment must be realized for groups of magnets to limit the number of powering circuits. An algorithm has bean established to self-consistently compute the tapering strengths of a given scheme, the RF phase required to compensate the energy loss and the required orbit corrections. Tapering scenarios, from coarse schemes to fine grained options are studied with the XSuite tracking code in terms of closed-orbit excursion and optics distortion. The results at the Z-pole (45.6 GeV) and $t\bar t$ (182.5 GeV) energies are discussed in detail.
Paper: MOPM031
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM031
About: Received: 28 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPM033
Coherent plane ground wave impact on the FCC-ee beam centroid
378
The FCC-ee is a collider, proposed after the LHC era, based on a ring of approximately 90 km of circumference. It will have to be able to accommodate beams running at half the z-pole and tt ̅-pole with vertical Interaction point beam size less than 40 nanometer at the z. In the present studies, coherent ground motions are being explored with particle tracking tools such as MAD-X and analytics code. The effect of parameters, such as harmonics, phase, orientation, defining global vertical sine waves like motion, are hence being detailed. At the time of writing, several lattices are subject to investigations. The differences in term of beam centroid for the main lattices and energy running will also be exposed. The impact of these motions of the machine detector interface quadrupoles is discussed.
Paper: MOPM033
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM033
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPM044
Long-term alignment stability of the SuperKEKB tunnel
418
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: 10 Jul 2025
MOPM052
Bayesian methods and differentiable models for optics studies at the ISOLDE facility
449
The Isotope mass Separator On-Line facility (ISOLDE) delivers a wide range of low-energy radioactive ion beams to its experimental users. To meet varying demands, the facility uses different target materials, ionization methods, and cooling/bunching techniques, with beam configurations potentially changing weekly. To model particle transport through the transfer lines, it is essential to reconstruct the beam's initial transverse phase space for each setup, achieved via quadrupole scan measurements. This work explores the application of Bayesian techniques and differentiable models to reduce the time required to perform the beam setup.
Paper: MOPM052
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM052
About: Received: 26 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
MOPM098
The mass production magnetic field measurement of the large aperture quadrupoles in HIAF
545
Currently the HIAF Project at IMP has reached the construction phase. The BRing is one of the key systems of HIAF, which is used to capture, accumulate, accelerate and extract the heavy ion beam injected by iLinac. The quadrupole magnets in BRing have large aperture (Ф260&Ф180) , large axial length(the total length of the magnet is reached 1140mm) and high integration field uniformity (±3×10-4). To measurement the magnetic field quality is very critical. The measurement aims to reach a reproducibility of 1.5×10-4 for the field integral, 2 ppm for the harmonic content for the main field and 0.2mm for the position of the magnetic center. A specially developed probe allows the simultaneous measurement of the field axis and quality. This thesis demonstrates that the system as it stands fulfils the high requirements with respect to the magnetic measurement and the magnetic center and thus provides the desired unique versatile equipment. The assessment was performed based on experimental results, direct calibration. The main defects treated are mechanical torsion and vibration of moving parts, electrical noise and power supply ripple.
Paper: MOPM098
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM098
About: Received: 28 May 2025 — Revised: 20 Jun 2025 — Accepted: 20 Jun 2025 — Issue date: 10 Jul 2025
MOPM102
Local and global betatron coupling correction based on beam position measurements in RHIC
560
Local coupling correction in Interaction Regions (IRs) and global coupling correction based on Base-Band Tune (BBQ) measurement have been performed routinely for RHIC operation. However, one still observes significant residual local coupling measured by beam position data. For the Electron-Ion Collider (EIC) project, betatron decoupling for the hadron beam needs to be improved to maintain a large horizontal to vertical beam emittance ratio (12:1). In this paper, we will analyze the cause for noticeable residual coupling in RHIC and propose an integrated local and global betatron coupling correction based on beam position measurements. We will also present experimental results from ML-based optimization of the local and global coupling in RHIC.
Paper: MOPM102
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM102
About: Received: 29 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPM103
A proposal of a momentum collimator in RHIC warm section for controlling experimental background at sPHENIX
563
One of the issues that the AuAu 100 GeV physics program in 2024 in RHIC encountered was background in the sPHENIX MVTX detector, which causes autorecoveries and preventing continuous data taking. Beam studies and track simulations performed to understand the source of the background and potential measures to control it have led to the conclusion that off-momentum particle loss was an issue. This article will focus on a proposal of a momentum collimator in warm sections in RHIC to control the MVTX background. We will elaborate the selection of the locations for the collimator, the strategy of generating substantial horizontal dispersion there, the required additional powering scheme for selected quads and the optimization of the figure-of-merit for momentum collimation.
Paper: MOPM103
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM103
About: Received: 29 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPM107
Status of construction of the new heavy ion synchrotron SIS100 at FAIR
567
The construction of the new FAIR heavy ion accelerator facility at GSI is progressing well. With the start of installation of SIS100 an important new milestone in project execusion has been reached. SIS100 is the first superconducting, fast ramped synchrotron with special design features dedicated to the acceleration of high intensity, low charge state heavy ions. The full performance of the specific functional systems, stabilizing the dynamic vacuum at operation with high Uranium intensities in combination with high repetition rates, was recently demonstrated at the SIS100 string test. Even under the influence of eddy current heating of the chamber walls at high ramp rates, its separatly cooled cryogenic vacuum system assures a stabilization of the residual gas pressure at extremely low values. The first straight sectors and arc modules have been installed heading towards a first hardware commissioning in 2026.
Paper: MOPM107
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM107
About: Received: 01 Jun 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
MOPM109
Beam-based alignment techniques for the FCC-ee
571
The Future electron-positron Circular Collider (FCC-ee) is a proposed lepton collider for high-energy particle physics succeeding the Large Hadron Collider (LHC). Its ambitious design goals demand excellent orbit and optics control and, therefore, set strict limits on alignment tolerances. One approach to relax the mechanical alignment tolerances is Beam-Based Alignment (BBA), where the offset between magnet and position measurement is determined and can later be used to steer the beam towards the magnetic centre using corrector magnets. One of the key challenges of the FCC-ee is developing an accurate and fast BBA strategy for quadrupoles and sextupoles. A parallel BBA technique is evaluated and compared in simulations for the baseline and an alternative lattice for FCC-ee using Xsuite and is presented in this paper.
Paper: MOPM109
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM109
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPS011
Improvement on beam-based alignment methods by reliability weighted average technique
607
Accurate determination of magnet centres seen by beams is the key to a successful commissioning of a particle accelerator storage ring. In this paper, several techniques to improve the beam-based alignment for a circular accelerator storage ring are introduced. Firstly, a formula to propagate the uncertainties from linear fitting is given. Secondly, a reliability weighted averaging technique based on uncertainties are applied to mitigate the impact of outliers. Thirdly, studies show that the accuracy and precision of quadrupole centre locations can be refined by using multiple corrector magnets in the process. Finally, to improve the efficiency when using multiple correctors, a monte-carlo technique is utilized. The resulting distributions of all BPM-to-Quad offset residuals derived from simulations are presented.
Paper: MOPS011
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS011
About: Received: 27 May 2025 — Revised: 31 May 2025 — Accepted: 01 Jun 2025 — Issue date: 10 Jul 2025
MOPS016
Multi-objective optimisation of the Diamond-II storage ring optics
619
The design performance of the 3.5 GeV Diamond-II low-emittance electron storage ring has been studied as a function of the linear and nonlinear lattice tuning parameters. A Multi-Objective Genetic Algorithm (MOGA) has been implemented to optimise both the beam lifetime and the injection efficiency for off-axis injection. The simulations have been run on 5 machine error seeds, including misalignment and field strength errors, to obtain a solution which is robust against machine imperfections. The results of the optimisation are presented alongside a comparison of the baseline performance.
Paper: MOPS016
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS016
About: Received: 28 May 2025 — Revised: 30 May 2025 — Accepted: 01 Jun 2025 — Issue date: 10 Jul 2025
MOPS040
Start to end commissioning simulations for SOLEIL II storage ring
698
This paper presents comprehensive start-to-end commissioning simulations for the SOLEIL II storage ring upgrade, demonstrating the feasibility of achieving an ultra-low emittance of 84 pm-rad at 2.75 GeV. We detail a multi-step correction strategy addressing challenges posed by the dense magnet arrangement and limited number of BPMs and correctors. Our simulations encompass first turn trajectory correction, beam-based alignment (BBA), and Linear Optics from Closed Orbit (LOCO) techniques. Results demonstrate the robustness of the correction scheme in the presence of realistic errors, showing successful recovery of design emittance, suitable dynamic aperture, and expected beam lifetime. This work provides insights into an efficient commissioning strategy for SOLEIL II, supporting rapid commissioning and full performance restoration for user operations.
Paper: MOPS040
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS040
About: Received: 27 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPS051
Light upgrade of the ESRF booster
730
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: 10 Jul 2025
MOPS065
Physics-driven specifications for the EIC ESR magnet power supply ripple
760
To avoid unacceptable proton emittance growth via beam-beam interaction, the EIC electron storage ring (ESR) requires very stringent tolerances for beam position and size stability at the interaction point. These tolerances imply tight specifications for several accelerator systems, including magnet power supplies (PS). While the magnetic field ripple requirements are most stringent at the betatron frequency and harmonics, the main PS challenges occur below ~1 kHz, where the ripple attenuation due to the vacuum chamber is insufficient. In the original ESR dipole powering scheme with ~20 families, the dipole PS current ripple specifications were found to be near or beyond the state-of-the-art. A recently adopted scheme with a single ESR main dipole PS relaxes these requirements to ~10 parts per million (ppm) rms, which is achievable. Additionally, the vacuum chambers of non-standard cross-sections required at some dipoles must be modified to match the field penetration time constant to that of the standard vacuum chamber. The paper presents the physics reasoning and simulations behind the latest PS ripple specifications, ranging from 5 to 100 ppm rms, depending on the magnet type.
Paper: MOPS065
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS065
About: Received: 28 May 2025 — Revised: 01 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPS092
Progress on beam dynamics studies for the ISRS isochronous ring spectrometer
793
A new lattice configuration is being developed for a compact,isochronous ring for the ISRS project, as an innovative spectrometer at HiE-ISOLDE. The design incorporates ten combined-function, canted cosine-theta (CCT) superconducting magnets, enabling the ring to fit within a constrained 5x5 meter hall space. This design presents significant challenges, particularly in accommodating the injection and extraction of a high beam rigidity beam, as the CCT magnets mechanical dimensions severely limit the space available for these subsystems. Using Bmad code simulations, the performance of beam injection and extraction, based on a high-field, superconducting septum and a fast magnetic kicker, is evaluated, along with the time-of-flight separation of various isotope ion products from selected nuclear reactions of interest.
Paper: MOPS092
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS092
About: Received: 09 May 2025 — Revised: 02 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPS116
Optics design status for the muon collider rapid cycling synchrotrons
806
The baseline design for the high-energy complex of a muon collider consists of a chain of pulsed synchrotrons spanning an energy range from 63 GeV to the target collision energy of 5 TeV. This chain incorporates both normal and hybrid synchrotrons, featuring a combination of fixed-field superconducting magnets and pulsed normal-conducting magnets. Initial optics designs for the chain of synchrotrons have been completed, with optimization efforts focused on minimizing the aperture dimensions required for dipoles and quadrupoles. Preliminary tracking studies have also been performed to evaluate emittance preservation throughout the acceleration process.
Paper: MOPS116
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS116
About: Received: 02 Jun 2025 — Revised: 02 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPS143
Feasibility studies for a new transfer line to a muon cooling demonstrator at CERN
840
In the context of ongoing research for a future muon collider, one of the primary challenges is the efficient production and cooling of muons. To address this, a proposal is being explored to construct a demonstrator at CERN for testing a cooling cell. This demonstrator would include a target and focusing system, a chicane around a dump, and a cooling channel. A potential site for this facility is the end of the existing TT7 tunnel, which was used as a neutrino facility in the early 1980s and is presently used for storage of radioactive waste. This paper outlines the initial design studies for the transfer line that will deliver 14 GeV protons from the Proton Synchrotron to the target. The design aims to minimize costs while meeting all geometric and optical requirements. The possibility of operating the line up to 20 GeV is also explored.
Paper: MOPS143
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS143
About: Received: 26 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
TUBN2
RHIC polarized proton operation in Run24
895
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: 10 Jul 2025
TUPB008
Spill optimization system improving slow extraction at GSI
956
Resonant slow extraction is routinely used to provide ion beams to various users. At GSI SIS18, two extraction methods are implemented: quadrupole-driven and Radio Frequency Knock Out (RF-KO) extraction. In either case, delivering a defined beam intensity (spill) without fluctuations or drifts is desired for an efficient beam usage. The Spill Optimization System (SOS) was developed to address this demand and improve the spill quality based on online spill monitoring. Developed using software-defined radio technology, it comprises a feedback controlling the spill rate and an optimization algorithm to improve the spill quality. In the case of RF-KO extraction, it controls the spill by generating tailored excitation signals for the KO exciter. For quadrupole-driven extraction, it produces a control signal for the tune ramp including tune wobbling to improve the spill quality. This contribution gives an overview on the systems and compares different usage scenarios.
Paper: TUPB008
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB008
About: Received: 26 May 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
TUPB009
The latest design for a future short-baseline neutrino beamline
960
The ENUBET and NuTAG projects propose the measurements of the $\nu_e$ and the $\nu_\mu$ cross sections at the relevant energies of Hyper-Kamiokande and DUNE. While ENUBET focuses on a fully instrumented decay tunnel to achieve a precise flux measurement, NuTAG proposes the use of silicon-pixel detectors to achieve the \textit{full tagging} of the parent meson and the daughter lepton. Both ideas have merged into the Physics Beyond Colliders (PBC) Short-Baseline Neutrino (SBN) beamline study, supported through the PBC initiative at CERN. If deployed at CERN, the SBN beamline would need to be compatible with the operation of the current injector complex including the new SHiP experiment, in particular with respect to the number of protons required. The beamline's intensity requirement must therefore be kept at a minimum. With that in mind, a full optimization of the beamline was conducted to maximize the production of hadrons while fulfilling pile-up and background constraints. This contribution presents the optimized beamline design, elaborating on the techniques used and challenges faced during the design process.
Paper: TUPB009
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB009
About: Received: 23 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 10 Jul 2025
TUPB057
Ultra-high spatial resolution in micron scale achieved by a practical cascade high energy electron radiography in HERPL
1095
As a new scheme, High Energy Electron Radiography (HEER) was considered as one of the novel mesoscale diagnostic methods for high energy density matter (HEDM) because of powerful penetration, high space-time resolution and large density dynamic diagnosis range. In this work, we R&D a practicle cascade HEER composed of a electromagnetic beamline and a permanent magnet HEER in High Energy Electron Radiography Research Platform in Lanzhou (HERPL). The field of view of the cascade HEER is about Φ3mm, and its total length is half that of the electromagnetic HEER with the same magnification. 50 MeV electron beams with picosecond pulse width bunch were used to image a TEM grid to study the spatial resolution. The excellent result was obtained with spatial resolution about 0.6 μm. In addition, electron bunch train and ultra-fast imaging acquisition system prepared for dynamic HEER were studied in this paper.
Paper: TUPB057
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB057
About: Received: 27 May 2025 — Revised: 01 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
TUPB091
Dose calculations for warm quadrupoles in the LHC off-momentum cleaning insertion
1143
Interaction Region 3 (IR3) of the Large Hadron Collider (LHC) houses the off-momentum collimation system, designed to remove particles with significant energy deviations. The interaction of the beam with this multi-stage collimation system generates particle showers that impact various elements, including quadrupole magnets in the straight section. Radiation exposure to magnet coils and spacers raises concerns about potential damage. The upcoming High-Luminosity (HL) LHC upgrade will significantly increase radiation doses, necessitating further assessments. While shielding inserts were added to the quadrupoles during a previous shutdown, further shielding may be required, prompting dose predictions through the HL-LHC era in the 2040s. This paper presents FLUKA simulations where the off-momentum proton and heavy ion losses in LHC Run 2 (2014-2018) and Run 3 (2022-2026) is estimated from Beam Loss Monitors. These estimates serve as normalization factor for calculating the dose deposited in the quadrupoles. These results are then extrapolated to HL-LHC operational parameters, offering unprecedented insight into the future IR3 radiation environment
Paper: TUPB091
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB091
About: Received: 26 May 2025 — Revised: 02 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
TUPB103
Status update of the laser-hybrid accelerator for radiobiological applications
1155
The Laser-hybrid Accelerator for Radiobiological Applications (LhARA) is a transformative approach to ion-beam therapy and radiobiological research. Serving the Ion Therapy Research Facility (ITRF), LhARA proposes to use a laser-driven proton and ion source, combined with advanced beam delivery systems, to provide highly flexible, high-repetition-rate, and ultra-short ion bunches suitable for groundbreaking studies in radiobiology. Following the recent publication of the LhARA Conceptual Design Report, the LhARA/ITRF project has entered a new phase of research and development. Here, we present a status update on recent LhARA progress. Highlights include improved understanding of the simulated beam generated at the source as well as subsequent impact on beam dynamics with co-propagating electrons, the latest descriptions of the FFA magnets including simulated fields and tune calculations in particle tracking and updated to beam delivery schemes in LhARA’s end stations for generating flexible beam conditions.
Paper: TUPB103
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB103
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
TUPM015
Design study for a transverse deflecting cavity based de-chirper
1196
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: 10 Jul 2025
TUPM026
Advanced beam tuning and beam measurements techniques in the CLEAR facility
1216
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: 10 Jul 2025
TUPM056
Beam control and characterization of the new SLS 2.0 booster-to-ring transfer line
1274
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: 10 Jul 2025
TUPM067
EPU coupling correction by Bayesian optimization in TPS
1311
APPLE-II type elliptically polarized undulators (EPUs) are critical for producing elliptically polarized light in modern synchrotron light sources. However, residual skew quadrupole components from manufacturing imperfections can couple horizontal betatron motion and dispersion to the vertical plane, changing beam size and degraded beam quality. This paper introduces a Bayesian optimization-based approach to correct these coupling effects for EPU66 at the Taiwan Photon Source (TPS). By constructing a two-dimensional coupling feed-forward table as a function of EPU gap and phase. Experimental implementation and verification with the closest-tune approach demonstrate the efficacy of this method. This article details the optimization process, mathematical framework, and experimental results, establishing a practical strategy for EPU coupling correction in TPS.
Paper: TUPM067
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM067
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
TUPM072
Two in-vacuum undulators developed for the Sirius
1326
The Shanghai Synchrotron Radiation Facility (SSRF) project team developed two in-vacuum undulators (IVUs) with a period length of 18.5 mm and a gap of 4 mm for the SIRIUS. This paper introduces the design and magnetic field measurements. The results indicate that with a gap range of 4-20 mm, the phase error is less than 3°, the quadrupole field is less than 37 Gs, the sextupole field is less than 83 Gs/cm, and the octupole field is less than 84 Gs/cm².
Paper: TUPM072
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM072
About: Received: 27 May 2025 — Revised: 31 May 2025 — Accepted: 14 Jun 2025 — Issue date: 10 Jul 2025
TUPM085
An upgrade to the normal conducting miniature transport line for laser plasma accelerator-driven FELs
1349
In this contribution, we present advancements in upgrading the employed normal-conducting electron beam transport line at the JETI laser facility, University of Jena. To address spectral broadening caused by the large energy spread in Laser-plasma accelerators (LPAs), a transverse gradient undulator (TGU) with an energy acceptance of ΔE/E0 = ±10% has been developed. Although efficiently transporting the electron beam from the LPA to the TGU within this acceptance range required an optimized beam transport line too. Phase-space analysis for single particles across this energy range revealed that earlier transport line designs at KIT exhibited a nonlinear dependence of beam transverse position x on energy deviation, leads to beam dynamics complication. By incorporating combined dipole-quadrupole magnets, maintaining a transport line length of 2.9 m for 300 MeV beams, a linear relationship between transverse position x and energy deviations was achieved, with minimal variation in the phase x' (less than 2.4 × 10−4). This redesigned transport line meets the TGU's dispersion requirements, enabling more precise beam alignment and transport.
Paper: TUPM085
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM085
About: Received: 28 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
TUPS038
Low energy beam transport line design for the Sarajevo ion accelerator
1510
The University of Sarajevo Physics Department, in collaboration with CERN’s Accelerator Beam Physics group, proposes a compact linear accelerator design for applied physics research spanning from beam dynamics studies to material surface analysis. The Sarajevo Ion Accelerator (SARAI) consists of an electron cyclotron resonance ion source, a low energy beam transport line (LEBT) and a radiofrequency quadrupole (RFQ). The ion source can produce an array of ions extracted with 30 kV. This study presents an iterative parameter optimization method that suggests two LEBT optics: one for beam diagnostics and another for compact beam matching to the RFQ acceptance. The RFQ discussed here is a 750 MHz, 2.5 MeV/u RFQ, used for medical applications. SARAI RFQ aims at 0.5 - 2 MeV/u. A novel RFQ technology allows a significant reduction in footprint. This paper further discusses plans for source commissioning and potential research applications.
Paper: TUPS038
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS038
About: Received: 27 May 2025 — Revised: 02 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
TUPS045
A standalone radio frequency quadrupole accelerator for swift heavy ions
1524
The radio frequency quadrupole (RFQ) is known for bunching, focusing and acceleration of ion beam and more importantly, it does not require transverse focusing element like quadrupole magnets between accelerating cells compared to drift tube linacs. By pushing the limits of handling surface electric field between RFQ vanes, it is possible to make a standalone 352 MHz RFQ reaching 1.8 MeV/u energy gain for swift heavy ions upto mass to charge ratio (A/q) ≤ 4. Special RFQ vane material of cryo Cu* is considered by which surface electric fields can be pushed around 50 MV/m** and the whole RFQ is designed within a length of 5m which is substantially less than any RFQ + DTL combination of equivalent energy gain accelerator for heavy ions. Such systems are highly promising for compact medical LINACS and as well as standalone facilities for nuclear physics experiments. The adiabatic bunching and focusing inherently stabilize the beam dynamics at proper RFQ power and cavity tuning. We present the beam optics design using PARMTEQ code and RFQ cavity design along with thermal analysis using CST MWS. The error analysis is provided to support the design in terms of practical feasibility.
Paper: TUPS045
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS045
About: Received: 28 May 2025 — Revised: 01 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 10 Jul 2025
TUPS094
Diagnosing an In-Vacuum Undulator in the ALS storage ring
1598
The Advanced Light Source (ALS) has an in-vacuum undulator named “LEDA”. It was installed in 2019 and provides high-brightness, high-energy photons for the ALS macromolecular crystallography beamline, Gemini. The undulator is a hybrid design with a minimum gap of 4.3 mm, a magnetic period of 15 mm, and a photon energy range of 5–19 keV. When the device was commissioned in the ALS storage ring, it had a negligible impact on ring operations. Recently, there has been a measured degradation in storage ring performance correlated with the Leda gap. Prior to conducting an invasive magnetic measurement, we performed a suite of beam-based measurements to characterize Leda. Herein, we detail these measurements and share them with the accelerator community, who may find them useful when encountering similar challenges.
Paper: TUPS094
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS094
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
TUPS151
Preliminary study of beam dynamics for SDTL-Based 200 MeV energy upgrade of KOMAC proton linac
1640
Korea Multipurpose Accelerator Complex (KOMAC) proposes an energy upgrade of the 100 MeV proton linac. The design of the extended linac is based on a normal-conducting separated-DTL (SDTL) structure which has several advantages over other accelerating structures. The SDTL structure is the same as the DTL, however, unlike the general DTL, the quadrupole magnet is not placed inside the DT but is placed outside. This adds more flexibility to optimize the DT structure for better accelerating efficiency. In addition, since only 4 DTs are placed in the SDTL tank, a separated field gradient stabilization device is not needed, so it is known to be easier to manufacture and align than the general DTL. Our upgrade design consists of a beam matching section between the SDTL and the existing DTL, and 20 SDTL tanks each containing four drift tubes (DTs) with a doublet focusing lattice structure. Beam dynamics simulations were performed using an optimized DT structure to accelerate proton beams from 100 to 200 MeV. We report the preliminary beam dynamics study of the 200 MeV SDTL linac carried out at KOMAC.
Paper: TUPS151
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS151
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 06 Jun 2025 — Issue date: 10 Jul 2025
WEYD1
Assessing and increasing the sustainability of future accelerator based facilities
1681
The long term sustainability of future accelerators is now a crucial problem for our community. Many groups and collaborations are actively working in this area (e.g. European projects included IFAST and iSAS, RUEDI (STFC) has recently published a case study for the project lifecycle, Centre of Excellence in Sustainable Accelerators is now being vigorously pursued in the UK with CERN backing, European LDG working group, etc). This talk will review the wider community efforts and highlight where good progress is being made and where future efforts are planned or required.
Paper: WEYD1
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEYD1
About: Received: 10 Jun 2025 — Revised: 14 Jun 2025 — Accepted: 14 Jun 2025 — Issue date: 10 Jul 2025
WEBN2
A module for fast auto differentiable simulations
1706
The auto differentiable simulation is a type of simulation that outputs of the simulation contain not only the simulation result itself, but also its derivatives with respect to many input parameters. It provides an efficient method to study the sensitivity of the simulation result with respect to the input parameters and can be used in some gradient based optimization methods for fast parameter design optimization. In this paper, we report on the development of a fast auto differentiation module that can be used in many simulation codes.
Paper: WEBN2
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEBN2
About: Received: 20 May 2025 — Revised: 30 May 2025 — Accepted: 01 Jun 2025 — Issue date: 10 Jul 2025
WEPB002
Advancements in magnet power supply systems at KARA: enhancing stability, efficiency, and operational capabilities
1726
The Karlsruhe Research Accelerator (KARA) has undergone a significant modernization of its power supply infrastructure, including dipole, quadrupole and sextupole magnet systems. These updates, completed by replacing the storage ring quadrupole power supplies in summer 2024, introduce improved stability, reduced energy consumption, and advanced control capabilities. The new controls and control system integration enable new operational modes, including energy ramp-down to refill the machine or reduce radiation by dumping the beam at lower energy. This allows consecutive beam optics and collective effects testing at high beam currents without creating too high radiation losses. The upgrades to the quadrupole power supplies further support these advancements by improving compatibility with modern control systems, ensuring reliable and efficient operation, and enabling more flexible operation modes. This paper summarizes operational experience over a year and compares the performance of the new systems to the previous ones. It highlights improvements in control interfaces, reliability, and overall performance, showcasing the upgrades' benefits for KARA.
Paper: WEPB002
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB002
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 10 Jul 2025
WEPB010
RF design for a quadrupole resonator with a fundamental frequency of 325 MHz at IMP
1741
The Quadrupole Resonator (QPR), originally developed at CERN, is a dedicated radio-frequency characterization equipment for evaluating superconducting material. It employs the calorimetric compensation technique and has a surface resistance resolution of less than 1 nOhm, operaing over a wide range of parameters, such as tem-peratures, resonant frequencies and magnetic fields. As a part of R&D work of superconducting material for SRF application in particle accelerators. A QPR with operating frequency of 325 MHz has been developing at Institute of Modern Physics (IMP), CAS. In this paper, we present the detailed electromagnetic design of the QPR, the design focuses on reducing the risk of multipacting, field emis-sion (B<sub>pk</sub>/E<sub>pk</sub>) and mode overlapping (delta f = f<sub>QPR</sub>-f<sub>dipole</sub>), enhancing the attainable peak magnetic field (B<sub>sample</sub>/B<sub>pk</sub>). The electromagnetic simulation results indicate that the optimized structure has good electromagnetic performance. Additionally, the coupler design compatible with four QPR modes will be introduced. The cavity will be fabricated soon.
Paper: WEPB010
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB010
About: Received: 09 Apr 2025 — Revised: 31 May 2025 — Accepted: 31 May 2025 — Issue date: 10 Jul 2025
WEPB026
Magnetic design of the cSTART magnets
1788
The KIT project cSTART (compact STorage ring for Accelerator Research and Technology) aims to store ultra-short electron bunches in a very-large-acceptance compact storage ring. The magnetic lattice of the storage ring is laid out for a variety of beam optics, including ultra-low positive and negative alpha as well as isochronous optics. These put high demands on the magnet quality and alignment. The spatial constraints for the storage ring impose further challenges on the magnet design. In this contribution, we give an overview of both the challenges and solutions for the cSTART storage ring magnet design.
Paper: WEPB026
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB026
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
WEPB027
Compact quadrupole-sextupole magnet units for the FLUTE-cSTART injection line
1792
One of the major goals of the cSTART project (compact STorage ring for Accelerator Research and Technology) at KIT is injecting and storing ultra-short bunches from the FLUTE linac into a very large-acceptance compact storage ring. To cope with the spatial constraints of the injection line connecting FLUTE with the storage ring three meters above, compact quadrupole-sextupole magnet units were designed, fabricated, and characterised. In this contribution, we describe the magnetic design of these units and the underlying considerations, particularly with respect to cross-talk effects and their mitigation by design. We present the results of rotating coil and Hall probe measurements validating the magnetic design.
Paper: WEPB027
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB027
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 10 Jul 2025
WEPB036
Nanometer sensitive vibration measurement system R&D status for SuperKEKB final focus
1815
SuperKEKB, a double ring circular collider with 7 GeV electron and 4 GeV positron beams, utilizes “nano-beam collision scheme” in which low emittance beams collide at large crossing angle. Positional fluctuations of the colliding beams are predicted to have a deleterious impact on luminosity; therefore, it is important to measure position oscillation of its superconducting quadrupole Final Focus (FF) magnets. KEK has developed, in collaboration with Brookhaven National Lab, a stabilized pickup-coil system to measure the magnetic field center oscillations of FF quadrupoles. This system is currently undergoing checkout and calibration at KEK using a permanent magnet quadrupole as a FF stand-in. In this paper, we will report on the measurement system status and our calibration results. This work is relevant for any high-luminosity collider that uses few-nanometer sized beams such as the proposed future ILC and FCC-ee Higgs Factories.
Paper: WEPB036
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB036
About: Received: 27 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 10 Jul 2025
WEPB045
Performance Analysis and Stability Enhancement Plan for the Sextupole Magnet Power Supply in Storage Ring
1836
Since its official operation in 2016, the Taiwan Photon Source (TPS) has been dedicated to providing a stable and high-quality synchrotron radiation light source. The TPS storage ring is divided into 24 sections, each equipped with 7 sextupole power supply units, totaling 168 units. These power supplies are responsible for delivering precise and stable current to drive the sextupole magnets. This paper focuses on evaluating the long-term operational stability of the sextupole power supply system since its commissioning and proposes a targeted upgrade strategy to address potential reliability issues. To enhance overall system stability and yield, and to effectively reduce the frequency of beam trips caused by power supply faults, an upgrade plan involving the adoption of ultra-high-precision power supplies has been proposed. In addition, the removed high-precision power supplies will be repurposed as spares to improve system redundancy and fault response capability. The upgrade project is scheduled for full implementation by 2028. A pilot installation has already been completed in Cell 22, and successful electron beam storage was achieved at the end of 2024. Preliminary assessments suggest that, upon completion, the upgrade will reduce the number of beam trip events by approximately 2 to 3 times per year and decrease the total annual downtime by around 4 to 6 hours, thereby significantly improving the operational reliability of the TPS storage ring and the quality of service provided to users.
Paper: WEPB045
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB045
About: Received: 22 Apr 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 10 Jul 2025
WEPB048
Magnetic measurement of a decommissioned insertion device at the Canadian Light Source
1843
The Canadian Light Source has decommissioned three insertion devices in recent years, replacing each with upgraded devices. The decommissioned devices are planar undulators that have seen approximately 15 years of operation in a 2.9 GeV storage ring, two being out-of-vacuum devices with 45 mm and 185 mm periods and one being an in-vacuum 20 mm device. In this paper we present magnetic measurements of the decommissioned 185 mm device (U185) with comparisons against the original measurements from before it was put into service.
Paper: WEPB048
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB048
About: Received: 24 May 2025 — Revised: 30 May 2025 — Accepted: 31 May 2025 — Issue date: 10 Jul 2025
WEPB084
Design of normal conducting quadrupoles for the spin rotator section in the EIC electron storage ring
1915
The interaction region IR6 in the Electron Storage Ring of the planned Electron Ion Collider facility at Brookhaven National Laboratory includes a section to rotate the electron spin into or out of the longitudinal direction. This section consists of superconducting solenoids, and normal conducting dipoles and quadrupoles. The geometry and field gradient requirements of the quadrupoles pose a challenge in their design with regards to yoke saturation and thereby field quality. Electromagnetic design of one such quadrupole is the focus of discussion in this article. The design process involves optimization of the pole tip, yoke and conductor size using two and three-dimensional finite element method tools.
Paper: WEPB084
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB084
About: Received: 22 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
WEPM003
Layout optimization and comparison of a Carbon-ion gantry based on different mechanical structures
1956
Carbon ion therapy is one of the most effective radiotherapy methods for cancer treatment, offering superior dose conformality compared to conventional radiation therapies. The combination of carbon ion treatment with a gantry further enhances treatment effectiveness and safety. When designing a gantry, the magnet aperture must consider both the beam envelope and the beam position errors all along the gantry beamline. These errors may arise from magnetic field errors, imperfect magnet alignment, construction inaccuracies and mechanical design choices. A well-matched optics guarantees a low beam envelope; however, this does not always correspond to an optimization of the space occupied by the beam after introducing error sources and related corrections. Thus, a novel methodology that integrates optics and mechanical studies has been developed. By combining mechanical deformation analyses and optics correction optimization algorithms, this study provides a comprehensive solution for the HITRIplus carbon ion gantry design. A detailed analysis of the impact of two different design options for the supporting system of the SC magnets is provided.
Paper: WEPM003
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM003
About: Received: 27 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 10 Jul 2025
WEPM014
Impact of linear imperfections in the high luminosity LHC separation dipole magnets
1980
Magnetic field measurements have been performed after fabrication of new separation dipoles for the low beta-star insertion regions of the High Luminosity LHC project*. In this paper, the effect of the linear imperfections of these magnets on coupling, beam size and beta-beating are evaluated using MAD-X simulations. The results indicate that the impact of normal-oriented quadrupole errors are small and easily correctable, while for skew-oriented quadrupole imperfections corrections require a significant fraction of the arc skew quadrupoles strength. Subsequent simulation studies were therefore performed to devise potential mitigation strategies, the results of which are also reported here.
Paper: WEPM014
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM014
About: Received: 26 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
WEPM023
BESSY III orbit correction scheme layout and performance
2004
Currently in its Conceptual Design Phase (CDR), the 4th generation light source BESSY III aims to become a world-leading soft X-ray source, enabling numerous applications in metrology, life sciences, energy and catalysis materials, and many more. Its performance relies on ultra-low transverse emittances, achieved through the use of strong focusing magnetic elements that are sensitive to magnetic and alignment errors. If left uncorrected, these errors give rise to a distortion of the closed orbit, beta beating, linear coupling, and a stronger impact of resonances thus impairing the storage ring performance. In this work, we address how to devise an initial BESSY III orbit correction scheme. Two criteria were considered to find the optimal locations of Beam Position Monitor (BPM) and dipolar Corrector Magnet (CM). Different orbit correction scheme candidates are presented and their advantages and disadvantages are discussed. All calculations were performed in parallel with the Matlab toolkit Simulated Commissioning (SC) and its Python counterpart (pySC).
Paper: WEPM023
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM023
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
WEPM031
Simulation-based optimization of the injection of ultrashort non-Gaussian electron beams into a storage ring
2028
The compact STorage ring for Accelerator Research and Technology (cSTART) project at the Karlsruhe Institute of Technology (KIT, Germany) aims to explore non-equilibrium electron beam dynamics and injection of laser-plasma accelerator (LPA) bunches. The Very Large Acceptance compact Storage Ring (VLA-cSR) is also filled by a second injector that delivers ultra-short bunches from the Ferninfrarot Linac- Und Test-Experiment (FLUTE). Injection from FLUTE into the VLA-cSR is achieved via a complex 3D injection line featuring tilted deflections, negative dispersion, and extreme compression to femtosecond bunch lengths. From this transport, the bunch develops pronounced non-Gaussian tails; nevertheless, near the injection point, it is crucial to ensure matching to both the dynamic aperture and the periodic solutions of the storage ring dynamics. The 25 quadrupole magnets of the injection line make conventional optimization methods impractical. This contribution discusses the development of the magnet optics to meet these extreme requirements. The optimization task was divided into two parts: longitudinal compression was addressed using a surrogate model, while transverse matching is currently being pursued with Bayesian optimization.
Paper: WEPM031
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM031
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
WEPM034
Beam optics model and characterization for CERN's low-energy ISOLDE transfer lines
2040
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: 10 Jul 2025
WEPM053
On the optimization of the non-linear lattice of BESSY III
2093
Helmholtz-Zentrum Berlin plans to construct a fourth- generation greenfield synchrotron light source in the early 2030s to replace BESSY II, a 1.7 GeV machine that has been running since 1998. The optimization of the linear lattice already considers non-linear aspects, such as minimizing the necessary sextupole strength and, for the minimal case of two families of sextupoles, phase cancellation to reduce the resonant driving terms. In preparation for the final optimization of 8 sextupole families and the single octupole, different approaches are compared: multi-objective genetic optimization, for a lattice with given error sets and orbit correction on the one hand, and the minimization of the resonant driving terms and the detuning terms on the other hand. Here, analytic formulas are used, so after a single evaluation of the Twiss parameters, the driving terms can be determined for different combinations of sextupole and octupole values. The results will determine the strategy for optimizing the lattice’s non-linear behavior, i.e., dynamic aperture and momentum acceptance, taking the efficiency of the optimization into account.
Paper: WEPM053
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM053
About: Received: 26 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
WEPM063
Symmetric double-double bend lattice for a potential EUV diffraction limited upgrade of the HLS
2113
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: 10 Jul 2025
WEPM079
Analysis of resonance lines and working points of the HALF storage ring lattice
2156
The Hefei Advanced Light Facility (HALF) storage ring employs a hybrid six-bend achromat lattice with long and short straight sections. In this paper, main resonance lines of on- and off-momentum dynamic apertures (DAs) of the HALF lattice are analyzed by using frequency map analysis and considering $\beta$-beat. The combined effect of a fifth-order structural resonance and a half-integer non-structural resonance can induce notable particle loss in off-momentum DAs over a certain range of negative energy deviations. However, it has a limited impact on local momentum aperture even with relatively large $\beta$-beat. Using the analysis of resonance driving term fluctuations, the HALF lattice with a new working point is studied, which exhibits a significantly improved 6D DA in the direction of beam injection.
Paper: WEPM079
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM079
About: Received: 04 Apr 2025 — Revised: 29 May 2025 — Accepted: 30 May 2025 — Issue date: 10 Jul 2025
WEPM092
Investigating ion beam loss mechanisms at the SPS flat bottom
2187
The long injection segment (flat bottom) of the cycle in the Super Proton Synchrotron (SPS) used for filling the Large Hadron Collider (LHC) with Pb ion beams, exhibits strong beam losses and transverse emittance growth. During the 2024 run, large improvements of the beam transmission could be made such that record intensities could be delivered to the LHC. In particular, these improvements were enabled by operational measures such as working point optimization and a numerical compensation scheme for the 50 Hz ripple from the main quadrupole power converters. This paper provides a summary of these improvements, and presents recent advancements in particle tracking simulations of the SPS flat bottom, including effects such as intra-beam scattering and space charge in the presence of tune modulation induced by power converter noise. These simulations are compared with transverse and longitudinal beam measurements. The relative importance of each effect and their estimated impact on the future ion programmes at CERN are discussed.
Paper: WEPM092
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM092
About: Received: 27 May 2025 — Revised: 03 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
WEPM103
Studies on the large residual horizontal orbit in the SIRIUS booster
2215
SIRIUS, the Brazilian 4th-generation synchrotron light source, operates in top-up mode at a current of 200 mA. Despite previous optimizations, the storage ring injection system still requires improvements in efficiency, to attend the tight demands in terms of repeatability and charge per pulse. In this context, this work investigates the large residual horizontal orbit distortion in the booster, that cannot be corrected with the current orbit correction system. A method to mitigate the problem, based on displacing focusing quadrupoles horizontally will be analyzed. Additionally, a hypothesis to explain the origin of the distortion, based on dipole error correlations introduced by the magnet sorting algorithm, will be investigated.
Paper: WEPM103
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM103
About: Received: 28 May 2025 — Revised: 01 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 10 Jul 2025
WEPM111
Experimental validation of parallel quadrupole beam-based alignment at KARA
2229
The Karlsruhe Research Accelerator (KARA), a synchrotron light source and test facility, at the Karlsruhe Institute of Technology (KIT), offers excellent conditions for testing different Beam-Based Alignment (BBA) approaches. Classical BBA approaches estimate the offset between the magnet and the closest BPM for one magnet at a time, and the required time for the BBA scales linearly with the number of magnets. Therefore, this approach is unsuitable for large storage rings like the Future electron-positron Circular Collider (FCC-ee). The time required is reduced using parallel BBA, where the magnet offset for several magnets is determined simultaneously. In this contribution, we compare new methods of parallel and individual BBA for quadrupoles at KARA. The measurement results are complemented with simulations using Xsuite and optics measurements.
Paper: WEPM111
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM111
About: Received: 09 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
WEPM112
Characterization of beam optics considering fringe fields of quadrupole magnets in a LIPAc 5 MeV beamline
2233
The 5 MeV beamline of Phase B+ which is an intermediate commissioning stage of the Linear IFMIF Prototype Accelerator (LIPAc) consists of an MEBT, an MEBT Extension Line (MEL) where the SRF will be installed, a HEBT, and a beam dump. It has 17 quadrupole magnets, and some quads have small aperture-to-length ratios and are also densely installed in the MEBT and HEBT sections. In the early stages of Phase B+, we optimized the beam optics with the conventional hard-edge model for all the quads. However, we observed unwanted particle losses and discrepancies in the rms beam sizes between measurements and simulations due to significant fringe fields and magnetic interference. After considering the field maps and the magnetic interference of the quads in the beam optics, we could obtain the matching beam and reduce the particle losses. In this paper, we characterize the beam optics by comparing the transfer matrices with and without the fringe fields and the interferences using a conventional hard-edge model and a more accurate hard-edge model equivalent to the field maps.
Paper: WEPM112
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM112
About: Received: 16 May 2025 — Revised: 01 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 10 Jul 2025
WEPM114
Orbit error correction schemes for the Helium Light Ion Compact Synchrotron HeLICS
2236
The Helium Light Ion Compact Synchrotron (HeLICS) is an innovative synchrotron design for cancer treatment currently under development in the context of the Next Ion Medical Machine Study (NIMMS) at CERN. As part of the lattice design, the beam size around the HeLICS circumference is evaluated and the optics functions optimized in order to meet the aperture requirements imposed by the magnet design. Furthermore, the impact of orbit errors arising from magnet misalignments is addressed, taking into account the required margins and tolerances. Correction strategies are proposed to compensate these alignment errors and provide sufficient orbit correction.
Paper: WEPM114
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM114
About: Received: 22 May 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
WEPS003
Study of operation above half-integer random resonance in the J-PARC RCS
2244
In the 3-GeV Rapid Cycling Synchrotron (RCS) of the Japan Proton Accelerator Research Complex (J-PARC), the beam power ramp-up aiming to surpass the design of 1 MW enhances the space charge effect. It pushes the beam toward the structure resonance. To mitigate the beam loss, the operating point is required to be apart from the structure resonance as the beam power ramp-up. However, large beam loss was observed when the operating point was set near the half-integer resonance. Thus, the maximum beam power of the RCS is currently limited so that the beam does not overlap the structure resonance or half-integer random resonance. To address this issue and achieve the beam power ramp-up, we experimentally studied the half-integer resonance compensation using trim quadrupole magnets. In addition, detailed numerical simulations were performed to develop a better understanding. The experimental and numerical results of the operation above half-integer random resonance are presented.
Paper: WEPS003
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS003
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 10 Jul 2025
WEPS012
Beam loss simulations with space charge and octupoles for the SIS100 magnet quality assessment
2267
The components of the SIS100 synchrotron (FAIR facility) are presently under installation in the accelerator tunnel. The superconducting dipole magnets have been produced and the magnet field errors up to 7th order have been measured for all magnets. The superconducting quadrupole magnets are under production, the field error data for a part of the magnets is available. As a part of the magnet quality assessment, the particle tracking simulations are used to study the beam losses during the 1 sec beam accumulation at the injection energy. The tune settings for the slow extraction operation are considered. Direct space-charge effects and the Landau damping octupole magnets, which dominate the incoherent tune distribution, are included. In order to reduce the computational load and to increase the parameter resolution, a machine learning based optimizer is used in the accelerator and beam parameter studies.
Paper: WEPS012
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS012
About: Received: 23 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
WEPS022
Progress on experimental efforts to investigate CSR shielding effects
2290
A collaboration is underway to investigate the impact of CSR and shielding on the beam of various shapes as it passes through a chicane. Experimental efforts are being made at the Argonne Wakefield Accelerator (AWA) facility. Currently, the facility is equipped with two identical doglegs with reversing quadrupoles that allow doglegs to function as a chicane, and manually adjustable shielding gaps in dipole magnet chambers. A 6.4-ps-long flattop laser pulse is generated using alpha-BBO crystals, and linac phase is adjusted to either preserve the bunch length or slightly compress it through the chicane. While the expected beam behavior was observed during the initial experiment, the current chicane’s exceptionally large R56 (=0.45 m) rendered it sensitive to modulations from the alpha-BBO configuration. We have confirmed a new beam-based tuning procedure for BBO crystals at the AWA facility and its effect on modulations. We present the summary of experimental efforts to date and outline future plans.
Paper: WEPS022
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS022
About: Received: 28 May 2025 — Revised: 30 May 2025 — Accepted: 31 May 2025 — Issue date: 10 Jul 2025
WEPS028
Quadrupole pumping for bunch shortening in the Proton Synchrotron and Super Proton Synchrotron at CERN
2302
Quadrupole pumping is a longitudinal manipulation technique for bunch shortening, which works by modulating the RF voltage at twice the synchrotron frequency to excite bunch length oscillations. These controlled oscillations rotate the bunch in longitudinal phase space, with extraction set for when the bunch is shortest. Higher RF harmonics can also be used to linearise the synchrotron frequency distribution, reducing the formation of tails. Recently, quadrupole pumping has been proposed as a method for achieving ultra short bunches for proton-driven plasma wakefield accelerators such as the AWAKE experiment. In this contribution, we assess the performance of quadrupole pumping for the first time in the Proton Synchrotron (PS) and Super Proton Synchrotron (SPS) at CERN. Using simulations and beam measurements, we compare the effectiveness of this technique (without linearisation) against other bunch-shortening methods, including the unstable phase jump and the non-adiabatic voltage jump.
Paper: WEPS028
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS028
About: Received: 27 May 2025 — Revised: 03 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
WEPS045
Investigating the Impact of alternative LHC optics on accelerator backgrounds at FASER using BDSIM
2341
Alternative configurations around the ATLAS experiment are investigated aiming to reduce muon rates at forward physics experiments such as FASER and SND@LHC. The Geant4 toolkit BDSIM is used to propagate muons through a model of a section of the LHC and the TI12 tunnel, where the FASER experiment is located. We compare the muon rates in BDSIM with FASER data collected during dedicated tests in the LHC. Results show a significant worsening of the background with the non-nominal polarity configuration of the triplet quadrupoles, used in 2024. The horizontal crossing angle further increased the background, however a partial mitigation of approximately 10% was found using a set of orbit corrector magnets. Additionally, nominal triplet polarity was favorable for both vertical and horizontal crossing angles. This work served as benchmark of simulations that will be used to validate future configurations.
Paper: WEPS045
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS045
About: Received: 28 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
WEPS048
Design of non-linear kicker for Siam Photon Source II
2348
A non-linear kicker (NLK) is designed for the beam injection into the storage ring of Siam Photon Source II. The required deflection angle is 4 mrad, the effective length is 400 mm and the peak field is 100 mT at the horizontal position of 9 mm from the magnet center. The design is based on 8-wire configuration where the conductor position is symmetric along the xz and yz planes. The vertical size of ceramics chamber is determined by the vertical beam stay-clear at the magnet position, available space for magnet installation and feasibility of conductive coating process. Magnetic field calculation of the NLK is performed in Radia and Opera-3D. The octupole-like magnetic field with the field-free region at the magnet center minimizes perturbation on the stored beam. Nevertheless, position error of the conductors leads to excess dipole and quadrupole field components at the magnet center. Magnetic field distortion is also caused by Eddy current induced in the conductive coating in transient analysis. In this work, magnetic design and magnetic field calculation of the NLK is presented.
Paper: WEPS048
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS048
About: Received: 28 May 2025 — Revised: 30 May 2025 — Accepted: 30 May 2025 — Issue date: 10 Jul 2025
WEPS049
Development of stretched wire system for magnetic field measurement of magnets for Siam Photon Source II
2351
A stretched wire measurement system was developed for magnetic field measurement of magnet prototype for Siam Photon Source II. It is used for magnetic field integral measurement for characterization of multipole field errors, magnet centering and fiducialization of multipole magnets. The wire trajectory across magnet aperture can be either linear or circular. The maximum wire movement is ±100 mm in both horizontal and vertical directions with the positioning accuracy of ±2 µm. The system is built on a 3.2-m granite support which allows the maximum magnet length of 2.2 m and magnet weight of 2,500 kg to be measured. Effects of wire tension, scan region, pause time between measurements, wire movement speed, number of repeated measurements and number of data points have been studied. With the optimized measurement parameters, the repeatability of 3E-4 or better can be achieved for the normalized multipole components measured using the circular scan.
Paper: WEPS049
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS049
About: Received: 28 May 2025 — Revised: 30 May 2025 — Accepted: 30 May 2025 — Issue date: 10 Jul 2025
WEPS050
Electron cloud mitigation techniques for the FCC-ee
2354
The Future Circular Collider (FCC)-ee is a planned electron-positron collider under development. The future collider would be built in an about 91 km ring-shaped underground tunnel located beneath the French departments of Haute-Savoie and Ain, and the Swiss canton of Geneva. The FCC-ee may face challenges from electron cloud (e-cloud). The strongest effects are foreseen for the Z configuration, due to the highest number of bunches, which corresponds to the smallest bunch spacing, which is a key parameter for the e-cloud formation process. A high electron density in the beam pipe could limit the accelerator’s achievable performance through various mechanisms, such as transverse instabilities, transverse emittance growth, particle losses, vacuum degradation and additional heat loads on the inner surface of the vacuum chambers. In the design phase, the objective is to suppress the e-cloud effects in the FCC-ee. Therefore, effective e-cloud mitigation techniques, to avoid the e-cloud avalanche multiplication and its deleterious effects, are discussed in the paper.
Paper: WEPS050
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS050
About: Received: 27 May 2025 — Revised: 03 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
WEPS052
Investigating electron cloud formation in FCC-ee nested magnet designs
2362
The Future Circular Collider is an ambitious international proposal for a next-generation particle accelerator complex, building upon the successes of CERN’s Large Hadron Collider. Specifically, the FCC-ee is a future circular lepton collider. The baseline design for the FCC-ee features four modes of operation, with beam energies ranging from 45.6 GeV to 182.5 GeV. Electron cloud (e-cloud) could be a concern for the FCC-ee due to the high number of bunches foreseen for the Z configuration, which results in small bunch spacing. The bunch spacing is a key parameter for the e-cloud formation process, as very small bunch spacing could lead to the avalanche multiplication and its deleterious effects. Moreover, electron trajectories are strongly influenced by externally applied magnetic fields, which could trap electrons and alter their survival time inside the vacuum chamber. The concept of nested magnets, which involves overlapping dipole fields with quadrupolar and/or sextupolar gradients, is under investigation. This approach aims to increase the dipole filling factor and reduce the synchrotron radiation. In this paper, the nested magnets are studied from the e-cloud point of view.
Paper: WEPS052
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS052
About: Received: 27 May 2025 — Revised: 03 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
THPB013
The wire alignment method in a magnetic field measurement system
2526
In the magnetic field measurement system, a single-core CuZr wire is used in both the stretched-wire (SW) and pulsed wire measurement (PWM) systems. Before measuring the magnetic field of the undulators, the CuZr wire must be aligned with the center of the undulator mechanism. The SW system is then employed to locate the magnetic field center of the undulator. The traditional method involves using a theodolite and level to align the CuZr wire with the center of the undulator mechanism. However, for cryogenic permanent magnet undulators (CPMUs), superconducting magnets, or any magnets installed in a vacuum chamber, aligning the CuZr wire with the center of the mechanism using traditional methods presents challenges. In this paper, we propose a method that utilizes the wire's contact with the magnet to observe changes in resistance for positioning purposes, thereby overcoming the limitations of center alignment in chamber-surrounded undulator mechanisms.
Paper: THPB013
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPB013
About: Received: 22 May 2025 — Revised: 02 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
THPB014
A vibrating wire system for multipole magnets alignment in TPS
2529
An auto-scanning vibrating wire system for magnets centering alignment was developed at NSRRC. It is prepared for the replacement of magnets on the girder of TPS storage ring in case of malfunction and also as a pre-study topic of the TPS upgrade. With this system, both quadrupole and sextupole magnets were tested in the laboratory. This paper presents the system configuration and testing results.
Paper: THPB014
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPB014
About: Received: 29 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
THPB042
Design and first prototype results of PETRA-IV permanent magnet dipole-quadrupoles
2594
Permanent magnet-based dipoles will be an essential part of the future PETRA-IV light source at DESY. The bending magnets are combined-function DQ-magnets, which provide moderate focusing with a B/G ratio of about 0.03m. Each DQ consists of several C-shaped modules, one of the three types additionally having a stepwise longitudinal gradient. Several prototype modules have recently been manufactured. The paper describes the magnet design, compares manufacturing peculiarities, and discusses first magnetic measurement results.
Paper: THPB042
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPB042
About: Received: 26 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 10 Jul 2025
THPB045
Permanent magnet-based dipole-quadrupole magnet for SPring-8-II
2602
In recent years, permanent magnet (PM) based multi-pole magnets have become an increasing concern as a replacement for conventional electro-magnets for light sources. The PMs are possible to save both energy and costs for operating and construction the facilities due to the absence of a power supply and cooling system. They have other advantages such as less space without magnetic coils and fewer failures than the conventional electro-magnets. PMs have specific issues, such as the adjustability of the magnetic field, demagnetization, and temperature dependence. Solutions to these issues were already confirmed with dipole structures for SPring-8-II, a major upgrade project of SPring-8 to the fourth generation. We have extended the knowledge and schemes to a dipole-quadrupole combined-function magnet (DQM) that comes in a quadrupole structure. The DQM is readily splittable into an upper and lower half for installation of a vacuum chamber. The reproducibility of the field gradient with half-splitting was less than 0.1%, which is within the required value. We report on the design and trial-manufacture of the PM based DQM.
Paper: THPB045
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPB045
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
THPB047
Design and construction of a permanent magnet quadrupole at NSRRC
2606
Increasingly, synchrotron facilities are being developed as green accelerators focused on energy efficiency and low-emittance rings to achieve high brilliance. The emittance size of the electron beam is closely related to the number of bending magnets used. To economically upgrade and optimize the current synchrotron facility, it is crucial to minimize revisions to the existing infrastructure. As a result, more lattice magnets should be installed within the previously constrained achromat space to maximize the available area for the straight section. Consequently, permanent magnet technology offers significant advantages due to its compactness, lack of power consumption, and elimination of the need for cooling circuits with deionized water. This study presents the design of a hybrid-type permanent magnet quadrupole, which consists of permanent magnets and soft magnetic materials, similar to the hybrid configuration of insertion devices. The model, with a bore radius of 11.5 mm, achieves a magnetic field gradient exceeding 90 T/m. Additionally, the practical engineering process used to realize this design is described. Finally, the magnetic field performance is characterized.
Paper: THPB047
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPB047
About: Received: 27 May 2025 — Revised: 02 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
THPB051
Performance evaluation of additively manufactured pure copper radio frequency quadrupole by low-power RF and high-field gradient tests
2612
This paper presents studies on advanced accelerator technologies conducted under the I.FAST (Innovation Fostering in Accelerator Science and Technology) EU project, focusing on additive manufacturing (AM) advancements. AM, particularly powder bed fusion, is giving unique production capabilities for accelerator components. As a proof-of-principle, a full-size pure copper Radio Frequency Quadrupole (RFQ) was successfully manufactured earlier. Low-power RF tests and bead-pull measurements performed on this prototype confirmed the precise electromagnetic field distribution, validating design accuracy and repeatability. Furthermore, high-field gradient tests conducted in the CERN's DC pulsed measurement system showed that AM copper electrodes spaced of 94 µm can achieve gradients up to 42 MV/m. These promising results highlight the transformative potential of additive manufacturing in producing high-frequency accelerator components, advancing both precision and reliability.
Paper: THPB051
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPB051
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
THPB101
Study of a girder system for the Korea-4th Generation Synchrotron Radiation (4GSR) accelerator
2683
The Korea 4th-Generation Synchrotron Radiation (4GSR) accelerator requires exceptionally high mechanical stability to ensure reliable beam operation with an extremely small beam size. To achieve this, a robust grid-er system is essential for supporting accelerator components such as magnets, vacuum chambers, and beam position monitors (BPMs). The girder system must suppress vibrations originating from the ground to prevent disturbances in the electron beam trajectory, while also maintaining sufficient mechanical rigidity to support heavy components like electromagnets. In the Korea 4GSR project, the girder system is required to maintain a misalignment tolerance within ±100 μm and limit vibration amplitudes to less than 10% of the beam size to ensure beam stability. However, with a storage ring circumference of approximately 800 meters, meeting these specifications poses significant challenges. This study presents the development of a girder system using finite element analysis (FEA) methods to achieve both mechanical stiffness and adjustability, thereby ensuring the required beam stability.
Paper: THPB101
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPB101
About: Received: 23 May 2025 — Revised: 02 Jun 2025 — Accepted: 06 Jun 2025 — Issue date: 10 Jul 2025
THPM017
Uncertainty-Quantified Machine Model Construction Using Physics-Informed Gaussian Processes and Bayesian Optimization
2718
To construct a closed orbit model for an accelerator ring with intrinsic uncertainty quantification from orbit measurements, a physics-informed Gaussian Process model is proposed based on a stochastic ensemble of MAD-X lattices. Key advantages compared to LOCO (Linear Optics from Closed Orbits) include (1.) uncertainty-enabled orbit prediction in between BPMs (beam position monitors), (2.) fitting of a parameter distribution (dipole-like field errors) which inherently models uncertainty, (3.) incorporation of measurement uncertainty from BPM noise, and (4.) an active learning approach which can be more sample efficient than measuring an orbit response matrix. A case study is presented for the GSI heavy ion synchrotron SIS18 with various simulated applications, in particular constructing an effective machine model with minimal orbit uncertainty around the ring, and orbit correction to achieve minimal deviation at a specific location such as, e.g., the septum to control beam loss during slow extraction. This physics-inspired Gaussian Process regression approach shows potential to be applied to optics correction and further applications beyond closed orbit correction.
Paper: THPM017
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPM017
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
THPM018
Efficient accelerator operation with artificial intelligence based optimization methods
2722
Tuning injectors is a challenging task for the operation of accelerator facilities and synchrotron light sources, particularly during the commissioning phase. Efficient tuning of the transfer line is essential for ensuring optimal beam transport and injection efficiency. This process is further complicated by challenges such as beam misalignment in quadrupole magnets, which can degrade beam quality and disrupt operations. Traditional tuning methods are often time-consuming and insufficient for addressing the complexities of high-dimensional parameter spaces. In this work, we explore the use of advanced AI methods, including Bayesian optimization, to automate and improve the tuning process. Initial results, demonstrated on the transfer line of KARA (Karlsruhe Research Accelerator) at KIT (Karlsruhe Institute of Technology), show promising improvements in beam alignment and transport efficiency, representing first steps toward more efficient and reliable accelerator operation. This study is part of the RF2.0 project, funded by the Horizon Europe program of the European Commission, which focuses on advancing energy-efficient solutions for particle accelerators.
Paper: THPM018
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPM018
About: Received: 28 May 2025 — Revised: 29 May 2025 — Accepted: 30 May 2025 — Issue date: 10 Jul 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
2743
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: 10 Jul 2025
THPM035
MENT algorithm for transverse phase space reconstruction at SIRIUS
2758
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: 10 Jul 2025
THPM100
Optimization of Siam Photon Source storage ring using Badger
2898
Badger is optimization software created for the purpose of real-time accelerator tuning and operation. A range of optimization algorithms are available on this platform, implemented with both graphical and command-line user interfaces. This study shows the improvements in beam size, beam lifetime and related parameters at the Siam Photon Source storage ring following the application of Badger. The optimization results will be presented.
Paper: THPM100
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPM100
About: Received: 28 May 2025 — Revised: 29 May 2025 — Accepted: 29 May 2025 — Issue date: 10 Jul 2025
THPM116
Efficient data-driven model predictive control for online accelerator tuning
2931
Reinforcement learning (RL) is a promising approach for the online control of complex, real-world systems, with recent success demonstrated in applications such as particle accelerator control. However, model-free RL algorithms often suffer from sample inefficiency, making training infeasible without access to high-fidelity simulations or extensive measurement data. This limitation poses a significant challenge for efficient real-world deployment. In this work, we explore data-driven model-predictive control (MPC) as a solution. Specifically, we employ Gaussian processes (GPs) to model the unknown transition functions in the real-world system, enabling safe exploration in the training process. We apply the GP-MPC framework to the transverse beam tuning task at the ARES accelerator, demonstrating its potential for efficient online training. This study showcases the feasibility of data-driven control strategies for accelerator applications, paving the way for more efficient and effective solutions in real-world scenarios.
Paper: THPM116
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPM116
About: Received: 27 May 2025 — Revised: 02 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
THPS013
Damping of quadrupole oscillations with bunch-by-bunch longitudinal RF feedback for FAIR
2976
To damp undesired longitudinal oscillations of bunched beams, the main synchrotron SIS100 of FAIR (Facility for Antiproton and Ion Research) will be equipped with a bunch-by-bunch longitudinal feedback (LFB) system. It will consist of new broadband kicker cavities and a dedicated low-level RF (LLRF) system. The LFB helps to stabilize the beam, to keep longitudinal emittance blow-up low and to minimize beam losses via damping dipole and quadrupole oscillations for up to 10 bunches individually. The topology of the LLRF signal processing is validated in closed loop with beam in the heavy-ion synchrotron SIS18 at GSI for future integration into SIS100. In a recent SIS18 machine development experiment with two bunches at flattop, quadrupole oscillations were excited for one bunch and then damped with a prototype setup of the LFB system using an existing magnetic alloy cavity as dedicated kicker cavity. This paper presents the test setup, the results of this experiment, and the proposed LLRF topology of the closed-loop LFB system. This validates a core part of the final SIS100 system.
Paper: THPS013
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPS013
About: Received: 19 May 2025 — Revised: 01 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025