synchrotron
MOYD1
Review of nonlinear resonances in acclerators and storage rings
13
Review of nonlinear resonances in accelerators and storage rings; including a discussion of chaos, particle diffusion and dynamic aperture
Paper: MOYD1
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOYD1
About: Received: 23 Apr 2025 — Revised: 05 Jun 2025 — Accepted: 06 Jun 2025 — Issue date: 05 Nov 2025
MOPB054
Evaluation of coating thickness and thermal deposited power for nonlinear in-vacuum kicker
173
This paper presents a comprehensive evaluation of the relationship between titanium coating thickness and thermal deposited power in the ceramic chambers of the Nonlinear In-vacuum Kicker (NIK) system, a critical component in synchrotron light sources. The study focuses on optimizing the coating thickness to minimize magnetic field attenuation and thermal load, thereby enhancing the performance of the NIK system. Through simulation analysis, we demonstrate that a titanium coating thickness of 5 μm provides an optimal balance between magnetic field attenuation and thermal load management. Additionally, the uniformity of the coating layer is found to significantly impact the system's stability and efficiency. The findings offer valuable insights for the design and operation of NIK systems in synchrotron facilities, particularly for the Taiwan Photon Source (TPS).
Paper: MOPB054
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPB054
About: Received: 07 May 2025 — Revised: 08 Oct 2025 — Accepted: 08 Oct 2025 — Issue date: 05 Nov 2025
MOPB065
Application of fast algorithms to calculate dynamic and momentum aperture to the design of ALBA II
197
In synchrotron light sources, the non-linear magnetic fields and Touschek scattering limit the stability of electron motion, determining the dynamic aperture (DA) and the momentum acceptance (MA). Optimizing both the DA and the MA is crucial to maximize injection efficiency and the beam's lifetime, but it is numerically expensive. We implement recently developed algorithms that speed-up their calculation in CPUs: Flood Fill and Fast Touschek Tracking (FTT). Applying these to the analysis of the ALBA II lattice and comparing them to the existing methods, we obtain rigorous and faster results using Flood Fill, and ones with a slight loss of accuracy for FTT.
Paper: MOPB065
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPB065
About: Received: 31 Mar 2025 — Revised: 30 May 2025 — Accepted: 01 Jun 2025 — Issue date: 05 Nov 2025
MOPB074
SOLEIL II project: entrance in the construction phase
212
SOLEIL II is the French upgrade project to build the science of tomorrow with synchrotron light radiation. Providing the highest brilliance in its class while maintaining the radiation range from IR to hard X-rays, the project is an ambitious triple upgrade of the SOLEIL facility: accelerators (new booster and storage ring), 29 beamlines and 3 laboratories, and an information technology transformation plan. High Order Achromat based on multi-bend achromat lattices will be used to replace both the storage (SR) and booster rings of the Synchrotron SOLEIL. The achieved equilibrium emittance of the SR (below 100 pm.rad, 354 m, 2.75 GeV) is about 50 times smaller than that of the existing Storage Ring (4000 pm.rad). To ensure the technical feasibility, an intensive R&D phase based on extensive numerical simulations, prototyping and measurements has been carried out. This paper presents the latest status of the project, the updated timeline, and describes the main results obtained so far in terms of performance and the prototypes launched in many technical domains (lattice, magnets, insertion device, vacuum, alignment…).
Paper: MOPB074
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPB074
About: Received: 03 Jun 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 05 Nov 2025
MOPB075
SOLEIL synchrotron light source lastest news
216
The synchrotron SOLEIL is France's 2.75 GeV third-generation synchrotron light source and serves as a cutting-edge research laboratory dedicated to advanced experimental techniques for matter analysis at the atomic scale. It also functions as a service platform accessible to both scientific and industrial communities. This abstract highlights the performance of the accelerators, which deliver exceptionally stable photon beams to 29 beamlines. Key figures of merit from the past year are reported, along with a review of several incidents and the lessons learned to prevent recurrence. Additionally, major research and development efforts addressing component obsolescence are outlined. The status of the LINAC upgrade is also discussed, alongside plans to use SOLEIL's current accelerator as a test bench to validate and precommission critical equipment for the forthcoming SOLEIL upgrade.
Paper: MOPB075
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPB075
About: Received: 02 Jun 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025
MOPM013
Modelling resonant depolarisation
298
For the FCC-ee collider it is planned to, in regular intervals (minutes), measure the average beam energy of the circulating electron and positron beams with a relative precision of $10^{-6}$ or better, using the method of resonant depolarisation with pre-polarized pilot bunches. In this article, we study basic systematic effects and ultimate uncertainties that may arise in this kind of measurement. To do so, we carry out simulations for a simple model representing an ideal situation, where an ensemble of particles with energy spread is subjected to synchrotron oscillations and to perfect spin motion. We assume an initial spin orientation in the vertical direction for all particles. The behavior of the spin is explored as an exciter frequency is swept slowly or rapidly, and in either direction,through the spin resonance.
Paper: MOPM013
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPM013
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 05 Nov 2025
MOPM026
Baseline concept and future prospects for the FCCee collider top-up injection
350
The FCC-ee (Future Circular Collider) is a high-luminosity lepton collider study at CERN. Strong effects from quantum fluctuations, beamstrahlung, and Bhabha scattering limit the expected lifetime to well below one hour. Top-up injection continuously refills the colliding bunches to maximize the integrated luminosity. The current baseline aims at using conventional on-axis injection and a thin magnetic septum. However, the beam size at higher energy modes and the limited off-energy dynamic aperture at lower energy modes make the on-axis condition challenging to achieve. The conventional scheme also raises machine protection concerns, as the circulating beam is subject to a fast one-turn bump towards the thin septum during the injection process. This contribution presents the status of the top-up injection scheme for every energy mode of the FCC-ee collider. We then discuss the existing challenges and potential variations to the baseline scheme in view of mitigating operational challenges and machine protection risks.
Paper: MOPM026
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPM026
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 05 Nov 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-IPAC2025-MOPM031
About: Received: 28 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025
MOPM049
Longitudinal wakefield implementation in the circulant matrix model
437
The influence of longitudinal wakefields on the beam dynamics in electron-positron colliders, particularly their role in beam instabilities such as Transverse Mode Coupling Instability (TMCI) and other transverse-longitudinal effects, necessitates a robust approach to accurately model these effects. This work focuses on the implementation of wakefield effects in the Circulant Matrix Model (CMM), a linear model that can facilitate the representation of these instabilities. We study the impact of potential well distortion and synchrotron frequency shifts due to longitudinal wakefields for FCC-ee and implement these effects in the CMM. The implementation is benchmarked against reference multiparticle tracking simulations to validate its accuracy in predicting longitudinal wakefield-driven instabilities. Results enable further studies featuring longitudinal wakefields for collider designs and operating machines.
Paper: MOPM049
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPM049
About: Received: 26 May 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 05 Nov 2025
MOPM072
Status of the DELTA synchrotron light source
494
DELTA, a 1.5-GeV electron storage ring facility operated by TU Dortmund University in Germany, celebrated its 30th anniversary in fall 2024. During its time in operation, the facility has been continuously developed to provide synchrotron radiation (SR) users with the most reliable and attractive radiation source possible. This includes continuous improvements of electron beam stability and lifetime, the installation of a new 7-T superconducting wiggler magnet with a specially adapted SR outlet chamber, as well as the integration of a second solid-state amplifier-driven radiofrequency system. In recent years, there have also been many exciting developments in the field of accelerator physics. These include the construction of a facility for generating ultrashort and coherent SR pulses, studies involving laser-induced terahertz radiation, and experiments conducted in single-electron mode that complemented ongoing research activities. Furthermore, projects focusing on intelligent system control using machine learning methods were successfully implemented. This report summarizes the most significant developments over the past years.
Paper: MOPM072
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPM072
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 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-IPAC2025-MOPM107
About: Received: 01 Jun 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 05 Nov 2025
MOPS005
Adiabatic capture in high-intensity, high-power rings
592
Finding the optimal RF voltage ramp to capture coasting beams in high intensity rings has been the subject of ongoing study for many decades. We are motivated to revisit the topic with a view to capturing coasting, stacked beams in a future high intensity, high power FFA. However, the results have general applicability. We compare various voltage laws including linear, bi-linear and iso-adiabatic through simulation and experimentally, making use of the ISIS synchrotron. Making use of longitudinal tomography, we seek to establish the voltage program that minimises the captured beam emittance.
Paper: MOPS005
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPS005
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025
MOPS015
Exploring the null space of the chromaticity response matrix at the Diamond Light Source
615
Many different techniques have been investigated at Diamond for optimising sextupole strengths*. One method not previously studied is to exploit the null space of the chromaticity response matrix. By performing a singular value decomposition (SVD) of the chromaticity response matrix, combinations of sextupole strengths are identified which alter the nonlinear lattice whilst keeping the chromaticity unchanged. Applying these sextupole strength changes opens an avenue to improve the beam lifetime and the injection efficiency at fixed chromaticity, thereby preserving the instability thresholds from collective effects. The results of applying this technique are presented both for beam tracking simulations for the Diamond-II lattice, including machine errors, and for machine-based measurements on the present Diamond synchrotron.
Paper: MOPS015
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPS015
About: Received: 28 May 2025 — Revised: 30 May 2025 — Accepted: 01 Jun 2025 — Issue date: 05 Nov 2025
MOPS034
Increasing single-bunch intensity limit at ESRF-EBS with high coupling
679
Synchrotron radiation light sources normally operate at a low coupling between the transverse planes in order to achieve flat beams and produce high peak brilliance. Instead, operating at a high coupling has other advantages such as smaller emittance degradation due to intra-beam scattering, improved Touschek lifetime, and lower sensitivity to vibrations of the photon beam. Moreover, it has been suggested that a high coupling may enable achieving higher bunch currents thanks to sharing of the beam-induced wakefields between the transverse planes. We were able to take advantage of this effect to substantially increase the TMCI threshold at zero chromaticity and nearly double the single bunch current limit at high chromaticity at ESRF-EBS.
Paper: MOPS034
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPS034
About: Received: 14 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 05 Nov 2025
MOPS048
First options for an ESRF EBS upgrade lattice
722
A new lattice for the EBS is proposed as preliminary candidate for the next generation ESRF storage ring. This new optics would feature lower emittance, matched optics at all ID, transparency conditions for insertions and overall a net gain in brilliance coherence and flux. Due to the reduced dynamic aperture, on-axis injection with a low emittance beam would be a requirement in order to progress with these optics.
Paper: MOPS048
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPS048
About: Received: 27 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 05 Nov 2025
MOPS053
Applications of electron energy measurement based on resonant spin depolarization at BESSY II
737
An electron energy measurement based on resonant spin depolarization has been running permanently at BESSY II for several years. This high-precision energy measurement was set up primarily for users of synchrotron radiation for me- teorological applications from the Physikalisch-Technische Bundesanstalt (PTB). Recent investigations have led to a better understanding of the method and the possibility of shortening the measurement time. This allows for new obser- vations and the use of the energy measurement for different applications such as the model-free measurement of the natural chromaticity, the momentum compaction factor or synchrotron sidebands.
Paper: MOPS053
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPS053
About: Received: 27 May 2025 — Revised: 31 May 2025 — Accepted: 03 Jun 2025 — Issue date: 05 Nov 2025
MOPS056
Single electron storage at UVSOR-Ⅲ electron storage ring
745
We have started single electron storage experiments since 2021 at the UVSOR-Ⅲ storage ring with the aim of conducting fundamental research on electromagnetic radiation. At BL1U, which is a beamline dedicated to light source developments, we extracted undulator light in the UV wavelength range into the air and observed its intensity by a photomultiplier tube, as decreasing the electron beam intensity using a beam scraper. When the beam intensity became sufficiently small, we observed step-function-like intensity changes with a good SN ratio, each of which corresponded to a loss of one electron. Based on this technique, we confirmed the single electron storage. After establishing the technique, we conducted some experimental studies on undulator radiation from single electron. We will present the latest results at the conference.
Paper: MOPS056
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPS056
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 05 Nov 2025
MOPS063
10 years operation of the Solaris storage ring
756
The SOLARIS storage ring, Poland’s first synchrotron light source, has marked a decade of successful operation, contributing significantly to scientific research and technological advancement. Commissioned in 2015 and inspired by the innovative design of Sweden’s MAX IV Laboratory, SOLARIS exemplifies the effectiveness of international collaboration in cutting-edge accelerator technologies. Over the past 10 years, the facility has maintained high performance and reliability (97% availability), delivering high-quality photon beams to researchers in diverse fields. Continuous improvements in the accelerator systems, such as enhanced beam stability due to SOFB and FOFB implementation, and optimised maintenance schedules, have enabled SOLARIS to meet the growing demands of the scientific community. A key focus has been the development of new beamlines and experimental stations, broadening the scope of available research capabilities. Looking ahead, SOLARIS aims to further expand its infrastructure (linac upgrade, top-up injection) and enhance beamline performance, ensuring its continued role as a hub for innovation and scientific excellence.
Paper: MOPS063
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPS063
About: Received: 28 May 2025 — Revised: 30 May 2025 — Accepted: 31 May 2025 — Issue date: 05 Nov 2025
MOPS074
The Novosibirsk fourth-generation light source SKIF development status
772
SKIF (Russian acronym for Siberian Circular Photon Source) – fourth-generation light source under construction in Novosibirsk. Natural emittance (at zero beam current and absent betatron coupling) of the SKIF is 72 pm at 3 GeV beam energy and 476 m circumference. Only two families of sextupoles provide horizontal and vertical dynamic apertures of 12 mm and 3.5 mm, respectively, and energy acceptance more than 5%. The flexibility of the lattice allows the beta functions to be changed in center of straight sections in a wide range from 0.5 m to 16 m, which opens up additional experimental possibilities for users. The paper presents status of development the SKIF project.
Paper: MOPS074
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPS074
About: Received: 01 Jun 2025 — Revised: 02 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025
MOPS076
Coupling of codes for modeling high-energy-density conditions in fourth generation light sources
774
As previously described*, high-intensity beams of ultra-bright light sources present new machine protection concerns by creating high-energy-density (HED) conditions in beam-intercepting components. Simulating these HED conditions required us to develop a method for coupling three codes for particle dynamics (elegant), particle-matter interaction (MARS/FLUKA), and hydrodynamics (FLASH). This paper discusses the recent advancements made toward this effort including the use of phase and temperature dependent thermal properties such as thermal conductivity and specific heat, transition from MARS to FLUKA, and improved liquid phase dynamics. For benchmarking purposes we compare simulation results with experimental data collected during the final run of the Advanced Photon Source (APS) ring as well as observations of collimator surface damage following the first user run of the upgraded machine. This methodology is also used to make predictions of collimator damage in future APS-Upgrade (APS-U) runs and to examine locations where synchrotron radiation may lead to HED conditions.
Paper: MOPS076
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPS076
About: Received: 30 May 2025 — Revised: 02 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025
MOPS083
Tune domain behavior of single magnet lattices
785
Single-sextupole and single-octupole lattices ``exhibit .. all the typical properties of more complicated mappings and dynamical issues'', including horizontal resonances of all orders $N$ with island tunes $Q_I$. In general both island tune response spectra and tune modulation drive spectra have multiple lines. Stable motion in transverse phase space is compromised when a pair of drive and response lines align. This vulnerability is illustrated by realistic examples from the Relativistic Heavy Ion Collider.
Paper: MOPS083
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPS083
About: Received: 11 May 2025 — Revised: 31 May 2025 — Accepted: 03 Jun 2025 — Issue date: 05 Nov 2025
MOPS140
Conceptual study of multi-turn injection for SIS100 as a long-term perspective
832
The SIS100 synchrotron, currently under construction as part of the FAIR project, is set to play a pivotal role in advancing high-intensity ion beam research. Reaching the FAIR design intensities for low charge-state heavy ions, e.g. the reference ion U28+ will, however, be challenging due to limitations of the existing SIS18 synchrotron serving as injector to SIS100. In the long-term, the integration of a new linear accelerator capable of delivering high-intensity ion beams at energies up to 200 MeV/u would open the possibility of direct multi-turn injection (MTI) into SIS100, bypassing the SIS18. This paper investigates the MTI process for U28+ beams, aiming to accumulate up to 5x1E11 particles per cycle with high efficiency and minimal particle losses on the electrostatic septum. We present a theoretical analysis of horizontal-plane MTI, outline achievable beam performance, and discuss system requirements. Additionally, the proposed layout and parameters of the MTI equipment are detailed.
Paper: MOPS140
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPS140
About: Received: 23 May 2025 — Revised: 13 Oct 2025 — Accepted: 13 Oct 2025 — Issue date: 05 Nov 2025
TUAN3
Comprehensive study of Robinson instability in active and passive higher harmonic cavities for bunch lengthening
874
Higher harmonic cavities (HHCs) play a critical role in storage rings by extending the bunch length, thus mitigating beam instability and increasing the beam lifetime. This study investigates the influence of Robinson instability on the bunch lengthening performance for both active and passive HHCs. A detailed comparison is conducted to analyze the Robinson instability thresholds* and the parameters of the HHCs** that govern the onset of instability. Simulation results and theoretical analysis are combined to provide guidelines for optimizing HHCs configurations to balance effective bunch lengthening with stability requirements. As illustrative examples, we consider an active normal-conducting HHC for Korea-4GSR , and a passive superconduting HHCs for PLS-II.
Paper: TUAN3
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUAN3
About: Received: 05 Jun 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025
TUZD2
SPS-II project: Status update
903
Siam Photon Source II (SPS-II) is a 4th-generation synchrotron light source set to be constructed in Thailand, aimed at becoming a major synchrotron facility for Southeast Asia. It is designed with a 3 GeV low-emittance electron storage ring, featuring a DTBA lattice and a circumference of 327.6 meters. Recently, the design and machine parameters have been carefully revised, with a particular focus on optimizing vacuum performance and the main RF frequency to ensure beam stability and reliable operation. In parallel with the design phase, significant progress has been made in developing key prototypes, including magnets, vacuum chambers, and girders, through collaboration with local Thai companies.
Paper: TUZD2
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUZD2
About: Received: 28 May 2025 — Revised: 30 May 2025 — Accepted: 31 May 2025 — Issue date: 05 Nov 2025
TUPB015
Evaluating the feasibility of TPS high heat load components for high-current operation using TMSI
979
The Taiwan Photon Source (TPS) currently operates at 500 mA beam current, with future evaluations targeting 800 mA to assess the feasibility of high-intensity operation. This imposes significant thermal and mechanical challenges on high heat load (HHL) components, such as premasks, fixed masks, slits, and absorbers, in the storage ring and front end. To systematically evaluate the severity of existing designs, we developed the Thermal-Mechanical Severity Index (TMSI), which quantifies combined thermal and mechanical stresses, enabling targeted comparisons within component categories. Finite Element Analysis (FEA) simulations using ANSYS were conducted to provide detailed thermal and thermo-mechanical results, supporting the validation of the TMSI framework. TMSI streamlines component assessment, reduces the need for exhaustive case studies, and facilitates prioritization of redesigns to ensure the reliability and longevity of HHL components. This methodology represents a practical and efficient approach to advancing TPS design and operation for next-generation synchrotron performance.
Paper: TUPB015
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPB015
About: Received: 07 May 2025 — Revised: 02 Jun 2025 — Accepted: 13 Oct 2025 — Issue date: 05 Nov 2025
TUPB030
Characterisation of transverse proton beam losses at the CERN Super Proton Synchrotron
1033
The High-Luminosity LHC (HL-LHC) project foresees nearly doubling the design beam intensity of CERN's Large Hadron Collider (LHC). A particularly pressing issue is the observation of significant beam losses at the flat bottom in the Super Proton Synchrotron (SPS) that delivers these beams to the LHC. These losses arise from multiple factors: uncaptured beam losses that are generated during the bunch rotation in the Proton Synchrotron (PS) before the transfer to the SPS; large transient beam loading effects in the RF system during multi-turn SPS injections; and the diffusion of over-populated transverse tails, which reach aperture limitations. Dedicated beam measurements were carried out in the SPS as a first step towards untangling these losses. These studies aimed to disentangle the various loss mechanisms, with a focus on the halo population and potential correlations between transverse and off-momentum tails.
Paper: TUPB030
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPB030
About: Received: 25 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 05 Nov 2025
TUPB040
Development of a comprehensive Biosafety Management System for external user experiments at NSRRC
1056
The National Synchrotron Radiation Research Cen-ter (NSRRC) operates the Taiwan Light Source (TLS) and Taiwan Photon Source (TPS) accelerators and approximately 40 end stations, about 10 of which are dedicated to biological research. Biologists from around the world utilize these facilities to investigate the structures and functions of biomolecules and cells, advancing the life sciences. Given the potential risks associated with biological experiments, particularly those involving biohazards, ongoing risk management is essential to ensure biosafety, as protocol failures often caused by human error or inadequate technique can increase the likelihood of exposure. This paper outlines the biosafety management framework at NSRRC, which supports users in sample classification, document submission, and risk identification to facili-tate a safe and efficient experimental review process.
Paper: TUPB040
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPB040
About: Received: 22 May 2025 — Revised: 02 Jun 2025 — Accepted: 13 Oct 2025 — Issue date: 05 Nov 2025
TUPB041
Functional design of a wideband RF system for HeLICS synchrotron
1059
Within the framework of the NIMMS (Next Ion Medical Machine Study) initiative at CERN, a comprehensive design study is being performed for the Helium Light Ion Compact Synchrotron (HeLICS), a compact accelerator for hadron therapy. A key component of this facility is the radiofrequency (RF) cavity. Its proposed design is based on the wideband technology successfully implemented in the CERN PS Booster. It comprises four cells filled with FINEMET material that enable the acceleration of protons and $^4He^{2+}$ over a broad energy range. The cavity, designed to deliver a peak voltage of up to 2 kV within a frequency range up to 10 MHz, features a compact design to meet the stringent requirements of a compact medical accelerator. It operates in double-harmonic mode, to effectively reduce longitudinal line density and mitigate space-charge effects at low energy. The combination of compactness and operational flexibility positions this RF cavity as an optimal solution for compact synchrotrons, enabling more efficient, precise, and accessible hadron therapy for cancer treatment.
Paper: TUPB041
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPB041
About: Received: 21 May 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 05 Nov 2025
TUPB061
Development of a water cooling system for solid-state power amplifiers at NSRRC
1106
Since 2023, Solid-State Power Amplifiers (SSPAs) have been operational at the Taiwan Photon Source (TPS) of the National Synchrotron Radiation Research Center (NSRRC), Taiwan. The TPS employs two KEKB-type Superconducting Radio Frequency (SRF) cavities, with one cavity powered by a home-made 300 kW SSPA RF power system with a stored beam current of 500 mA. This study presents the design and implementation of the water cooling system for the SSPA RF station, addressing both system-level and module-level considerations.
Paper: TUPB061
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPB061
About: Received: 21 May 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 05 Nov 2025
TUPB105
A compact synchrotron for cancer therapy with helium ions
1159
In the frame of the Next Ion Medical Machine Study (NIMMS) collaboration based at CERN, a compact synchrotron for radiotherapy with high-intensity helium beams is designed. Interest in helium ions is growing in the major treatment centers, since they provide superior accuracy compared to protons, thanks to their sharper lateral penumbra, and higher linear energy transfer. Their properties lie in-between protons and carbon ions, without the fragmentation problems of the latter. Moreover, their lower magnetic rigidity allows helium-ion accelerators to be more compact than the large carbon-ion machines. The synchrotron design presented in this paper is based on normal-conducting dipole magnets at 1.65 Tesla and has a circumference of 35 meters. Optimized for helium ions, it can also accelerate protons, for treatment and particle radiography, and other species to smaller penetration depths. The design choices for the different systems are described taking into consideration the mechanical integration in a compact layout and operational flexibility. The technology readiness level is evaluated and R&D options to achieve higher performances and reduce energy consumption are identified.
Paper: TUPB105
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPB105
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025
TUPM025
Conceptual design of a compact synchrotron for proton-and-helium therapy facility
1212
In recent years, proton and heavy-ion therapy has become increasingly widespread in clinical applications, and has emerged as one of the important means for cancer treatment. The commonly used particle types for this therapy are protons and carbon ions. However, further research into the biological effect has found that helium ions have both high biological effectiveness and small penumbra characteristics, which enable more precise locate of the tumor while also effectively killing tumor cells. And the highest energy of the helium ions used in therapy is 235MeV/u. Therefore, the equipment size and cost required for helium ions therapy will be significantly less than that for carbon ions therapy. To this end, this paper proposes a design for a helium-ion therapy synchrotron that also possesses the capability for proton therapy. The design employs eight ultra-high field dipole magnets to achieve a compact envelope function. Additionally, the design incorporates both multi-turn painting injection and mismatched injection methods in two directions, significantly minimizing the use of bump magnets. This results in a highly compact accelerator structure.
Paper: TUPM025
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPM025
About: Received: 03 Apr 2025 — Revised: 30 May 2025 — Accepted: 03 Jun 2025 — Issue date: 05 Nov 2025
TUPM053
Design of a resonant slow extraction from the planned DESY IV booster synchrotron
1266
The planned upgrade of the synchrotron light source at DESY, Hamburg will include an upgrade of the booster synchrotron. We discuss the considerations for the design of a slow resonant extraction from this future machine. The implementation of a bent crystal as a potential septum shadower and/or as a septumless option is considered.
Paper: TUPM053
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPM053
About: Received: 26 May 2025 — Revised: 01 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 05 Nov 2025
TUPM060
Specification of insertion devices for ORION project at SIRIUS
1288
The pioneering ORION project will integrate a biosafety level 4 (BSL-4) laboratory with the SIRIUS synchrotron light source. The project includes three beamlines: TIMBÓ, HIBISCO, and SIBIPIRUNA, optimized for X-ray microscopy on biological materials. This study focused on evaluating Insertion Devices (IDs) for the TIMBÓ and HIBISCO beamlines, which demand high photon flux in the ranges of 3–20 keV and 16-40 keV, respectively. Achieving high photon energies with undulators in a 3 GeV synchrotron poses significant challenges. To address this, radiation emission calculations were performed for three ID types: in-air (IAU), in-vacuum (IVU), and cryogenically cooled permanent magnet (CPMU) undulators. With a numerical method based on SPECTRA* software, CPMUs were identified as optimal: a 2 m CPMU with a 14.6 mm period was identified for TIMBÓ, while HIBISCO ideal option is a 2 m CPMU with a 13.6 mm period. As a comparison of the types found for HIBISCO at 40 keV, CPMUs demonstrated approximately a 2.7x flux gain compared to IVUs, and IVUs about 3.8x the flux of IAUs. Further evaluations will consider also the impact on the electron beam dynamics and fabrication feasibility.
Paper: TUPM060
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPM060
About: Received: 29 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025
TUPM061
Spectrum-based alignment of SIRIUS undulators
1292
Recently, two SIRIUS beamlines, EMA and PAINEIRA, received their definitive insertion devices (IDs). Both IDs are in-vacuum devices (IVUs), the first of this kind at SIRIUS. Due to the proximity of the IVU cassettes to the electron beam, the spectrum emitted by these devices is highly sensitive to misalignments of the ID magnetic center. Such misalignments can result in photon flux losses, spectral shifts toward lower energies, and broadening of the resonance. This work presents the application of O. Chubar’s* spectrum-based alignment method to one of the new SIRIUS IVUs, aiming to optimize its performance at the beamline.
Paper: TUPM061
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPM061
About: Received: 22 Apr 2025 — Revised: 30 May 2025 — Accepted: 31 May 2025 — Issue date: 05 Nov 2025
TUPM068
First magnetic experience with APPLE X knot undulators for SLS 2.0
1315
The next generation of synchrotrons will have undulators with shorter periods, stronger magnetic fields, and thus higher radiation power. Consequently, concepts for reducing on-axis heat load will become more relevant. One possible idea is to introduce so-called APPLE “knot” undulators that shift the main energy peak off-axis. Thanks to almost on-axis injection, APPLE X undulators with a round vacuum chamber can be used for the upgraded SLS 2.0 at the Paul Scherrer Institute (PSI). This contribution presents an adaptation of the APPLE “knot” concept tailored to the needs of SLS 2.0 in the form of two-meter-long APPLE X undulators with a 36 mm period length and a gap of 11.5 mm. Our design faces the challenge of dealing with up to 16 different magnetization angles introduced by combining and merging NdFeB magnets into four arrays with peak fields around 1 T. Consequently, the magnetic design and the first measurement results are discussed with an outlook on magnet optimization.
Paper: TUPM068
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPM068
About: Received: 27 May 2025 — Revised: 30 May 2025 — Accepted: 30 May 2025 — Issue date: 05 Nov 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-IPAC2025-TUPM072
About: Received: 27 May 2025 — Revised: 31 May 2025 — Accepted: 13 Oct 2025 — Issue date: 05 Nov 2025
TUPM079
A report from ISBA24 (The 7th international school on beam dynamics and accelerator technology) in Chiang Mai, Thailand
1341
ISBA24 (The 7th International School of Beam Dynamics and Accelerator Technology) was held in Chiang Mai, Thailand, jointly hosted by Chiang Mai University, Hub of Talents in Particle Accelerators (operated by the Thailand Center of Excellence in Physics), Synchrotron Light Research Institute (Public Organization) and Hiroshima University. ISBA is a series of international accelerator schools initiated in 2018 at Hiroshima, Japan promoted by IINAS(IINAS-NX). ISBA24 was held from November 1 to 9, 2024. The school brought together over 80 participants, including 18 professors and experts, and 64 students from ASEAN countries and beyond. All participants enjoyed intense lectures, practical exercises, student presentations, and social events such as excursions and Thai northern style banquet. An overview of ISBA24 will be presented and human resource development in accelerator science will be discussed.
Paper: TUPM079
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPM079
About: Received: 28 May 2025 — Revised: 29 May 2025 — Accepted: 30 May 2025 — Issue date: 05 Nov 2025
TUPS035
TURBO – Enabling fast energy switching for hadron therapy with constant magnetic fields
1498
The energy layer switching time is a limiting factor for hadron therapy, precluding fast beam delivery and reducing treatment efficacy. For rapid energy switching the beam delivery system must be achromatic with zero dispersion over a large energy range. At the University of Melbourne, the TURBO project will utilise Fixed Field Accelerator techniques to demonstrate transport of a ±42% momentum spread beam around a 30° bend, with constant magnetic fields to eliminate the energy switching bottleneck. This will be demonstrated with an electrostatic Pelletron accelerator. A fast-switching energy degrader with thin diamond films has been designed to quickly change proton beam energies in the range 0.5-3.0MeV, covering the full clinical range when scaled up. A new design technique using nonlinear magnetic fields for energy-dependent focusing has been developed to minimise delivered beam variations. A novel method has been found to produce nonlinear permanent magnet arrays without custom magnets, enabling fast prototyping and reuse of magnets. With these innovations, the TURBO project will demonstrate rapid energy switching for hadron therapy to enable improvements in patient outcomes.
Paper: TUPS035
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPS035
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 05 Nov 2025
WEBN1
Empowering a broad and diverse community in beam dynamics simulations with Xsuite
1702
Xsuite is a Python toolkit for modelling and simulation of particle accelerators, which has been developed at CERN together with collaborators from other institutes over the past four years. The code has reached a mature development stage and has become the workhorse for several studies and applications, allowing the gradual replacement of legacy tools like Sixtrack, COMBI, PyHEADTAIL. This contribution provides an overview of the code capabilities and illustrates examples in different areas of accelerator science, including low-energy hadron rings for medical applications, high-intensity hadron accelerators, synchrotron light sources, high-energy hadron and lepton colliders.
Paper: WEBN1
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEBN1
About: Received: 26 May 2025 — Revised: 30 May 2025 — Accepted: 01 Jun 2025 — Issue date: 05 Nov 2025
WEPB030
Efficient nonlinear simulations of the fast corrector magnets for PETRA IV
1803
Fast orbit feedback systems are an important component in fourth-generation synchrotron radiation sources such as PETRA IV at DESY in Hamburg, Germany. These control systems are designed to stabilize the particle orbit, i.e., to correct deviations from the design orbit due to various disturbances. To that end, such a system employs fast orbit corrector magnets, which must be powered at frequencies up to the kilohertz range. This leads to significant eddy current effects that must be predicted via finite element simulations. Therefore, extensive simulation studies have already been conducted. These simulations did not, however, consider the magnetization curve’s nonlinearity since doing so requires prohibitive computational effort when using commercial software. Hence, we have constructed a dedicated method, based on a combination of the harmonic balance finite element method and homogenization schemes, to enable nonlinear simulations. This contribution outlines the general idea and application of our method to the corrector magnets of PETRA IV and presents the most important findings regarding the impact of the nonlinear magnetization curve on the magnet’s performance.
Paper: WEPB030
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPB030
About: Received: 05 May 2025 — Revised: 30 May 2025 — Accepted: 30 May 2025 — Issue date: 05 Nov 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-IPAC2025-WEPB045
About: Received: 22 Apr 2025 — Revised: 13 Oct 2025 — Accepted: 13 Oct 2025 — Issue date: 05 Nov 2025
WEPB049
Upgrade of the insertion device measurement benches and associated software at the ESRF
1847
The European Synchrotron Radiation Facility (ESRF) has built and characterized many insertion devices and magnets over the past decades. The magnetic measurements rely on dedicated benches, based on stretched wire for integral measurements and on hall probes for local measurements. A major upgrade of these benches is being developed. It includes new features such as coordinate measurents, upgraded acquisition boards and hall probes, and a new control software based on Python, HDF5 data format and Qt. The B2E software, used for computing synchrotron radiation and for shimming undulators, was completely refactored. This paper presents the architecture of these new benches, the status of the project and the first results.
Paper: WEPB049
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPB049
About: Received: 26 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 05 Nov 2025
WEPB050
Test coil-unit fabrication of Nb3Sn superconducting multipole wiggler for next generation light source in KEK-PF
1851
Recently, KEK PF has started developing a superconducting multipole wiggler (SC-MPW) for an application in next-generation light source ring. The SC-MPW is expected to be a key insertion device for the light utilization of a wide wavelength region by aiming at high-brightness and high-energy X-ray production while keeping the stored beam energy as low as 2.5 GeV. In addition, the short period length of multipole wiggler not only lowers the light spread and increases the effective photon flux, but also reduces the beam orbit amplitude, which leads to suppressing the emittance growth in a low emittance ring. In our application, the magnetic field more than 2.5 T is required on the central beam orbit even in a short period length less than 80 mm with a wide gap more than 30 mm that secures the beam orbit region. As we need to investigate the candidate of Nb3Sn wires and to study the coil-fabrication techniques which meet a use as multipole wiggler, PF has completed the first prototype-coil unit consisting of three poles and successfully conducted excitation tests at the low current. The detailed fabrication of test-coil unit and the prospects for high-current testing will be reported.
Paper: WEPB050
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPB050
About: Received: 25 May 2025 — Revised: 31 May 2025 — Accepted: 02 Jun 2025 — Issue date: 05 Nov 2025
WEPB054
Advanced power density mapping for FEA simulations of synchrotron accelerator high heat load components
1858
Accurately simulating the thermal and mechanical effects of undulator power density distribution in high heat load components requires precise power implementation in finite element analysis (FEA) models. This study presents a novel methodology utilizing intermediate programming to efficiently map complex undulator power density distributions onto FEA models. The approach enables the placement of power density values (e.g., W/mm²) on each element surface while simultaneously calculating the grazing angles based on the insertion device's power source geometry. By automating these processes, the methodology significantly reduces the time and effort required for engineers to implement detailed power distributions in FEA simulations. This advancement not only ensures higher accuracy in modeling but also streamlines the workflow, allowing for faster evaluation and optimization of high heat load components in synchrotron radiation facilities. The proposed framework offers a practical solution for integrating advanced undulator power profiles into engineering analyses, enhancing both efficiency and reliability.
Paper: WEPB054
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPB054
About: Received: 07 May 2025 — Revised: 30 May 2025 — Accepted: 13 Oct 2025 — Issue date: 05 Nov 2025
WEPB083
The cavity combiner development for TPS SSPA tower at NSRRC
1912
NSRRC builds four home-made solid state power amplifier towers to provide 300 kW for one superconducting RF cavity at TPS. The power combining tree of one tower is two-stages structure with a complex wire connection. In order to simplify the wire connection and increase the power combining efficiency, we devote resources to develop the cavity combiner. In this study, a 21-ports cavity combiner is designed and manufactured. The RF properties, S11 and S21, of output port were simulated and measured to evaluate the combining efficiency.
Paper: WEPB083
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPB083
About: Received: 29 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 05 Nov 2025
WEPM002
Effects of new SIRIUS IVUs on electron beam dynamics
1952
Recently, two SIRIUS hard X-ray beamlines, EMA and PAINEIRA, were upgraded by replacing their previous insertion devices (IDs) with SIRIUS’s first in-vacuum undulators (IVUs). These new IDs have a period of 18.5 mm and can achieve a peak magnetic field of 1.24 T at a minimum gap of 4.3 mm. This paper reports on the effects of these new light sources on the electron beam, including static and dynamic orbit distortions, impacts on optics, injection efficiency, and changes in the storage ring’s equilibrium parameters.
Paper: WEPM002
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPM002
About: Received: 27 May 2025 — Revised: 31 May 2025 — Accepted: 01 Jun 2025 — Issue date: 05 Nov 2025
WEPM032
Online optimization of beam lifetime by Bayesian Optimization in TPS
2032
The beam lifetime in synchrotron light sources is critically influenced by nonlinear beam dynamics, particularly in low-emittance storage rings where the Touschek effect dominates. At the Taiwan Photon Source (TPS), a third-generation 3 GeV storage ring, optimization of harmonic sextupole magnet strengths has been conducted using Bayesian Optimization (BO) techniques to minimize beam loss monitor (BLM) readings and thereby enhance beam lifetime. This study demonstrates an integrated approach to nonlinear optics tuning using machine learning, with constraints on chromaticity correction. The experimental implementation involves tuning harmonic sextupole families. Results indicate significant improvements in lifetime while maintaining machine stability, demonstrating the potential of data-driven control in modern accelerator operations, establishing this technique as a powerful tool for synchrotron light source operation. This paper details the implementation, experimental validation, and performance analysis of BO in optimizing beam lifetime at TPS.
Paper: WEPM032
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPM032
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 05 Nov 2025
WEPM037
Design progress of the booster synchrotron for Siam Photon Source II
2047
The Siam Photon Source II (SPS-II) represents Thailand’s second synchrotron light source, designed to enhance the region’s scientific capabilities by providing high-energy, high-intensity synchrotron light for both academic and industrial research. The SPS-II will be situated in the Eastern Economic Corridor of Innovation (EECi) in Rayong Province. The SPS-II accelerator complex comprises three main parts: a linear accelerator (linac), a 3 GeV booster synchrotron, and a 3 GeV electron storage ring. The booster synchrotron is specifically designed to ramp beam energy to 3 GeV with a repetition rate of 2 Hz. This paper provides the latest update on the design of the booster synchrotron and related ramping studies. The study investigates the impact of magnetic field errors, multipole field imperfections, and alignment tolerances on beam parameters, with particular emphasis on the energy ramping process to ensure efficient and stable accelerator operation.
Paper: WEPM037
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPM037
About: Received: 28 May 2025 — Revised: 13 Oct 2025 — Accepted: 13 Oct 2025 — Issue date: 05 Nov 2025
WEPM048
Demonstrating beam splitting through stable islands formed by the third-order resonance at the CERN Super Proton Synchrotron
2085
In recent years, several new beam manipulation techniques have been proposed that exploit the crossing of nonlinear resonances and the use of stable islands of the transverse phase space. One such manipulation is a novel approach to slow extraction, which combines particle trapping in stable islands with the use of bent crystals to reduce losses on the extraction septum. As a first step towards testing this approach, measurements were performed at the CERN Super Proton Synchrotron (SPS) to demonstrate beam splitting using stable islands of the third-order resonance generated and controlled by sextupole and octupole magnets. The phase-space topology was reconstructed by displacing the beam and observing the turn-by-turn evolution of the signal of the beam position monitors. The beam splitting was achieved by varying both the machine tune and the radial steering of the beam. The measurement results were found to be in excellent agreement with the tracking simulations.
Paper: WEPM048
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPM048
About: Received: 19 May 2025 — Revised: 31 May 2025 — Accepted: 01 Jun 2025 — Issue date: 05 Nov 2025
WEPM071
Direct interpretation of coherent synchrotron radiation modeling from the Lienard-Wiechert equation with shielding
2125
Coherent Synchrotron Radiation (CSR) plays a critical role in beam dynamics, significantly influencing beam shape and energy characteristics in particle accelerators. This study investigates the CSR effect through a comprehensive numerical approach, starting from the fundamental Lienard-Wiechert equation and utilizing an explicit, non-approximated methodology to explore beam energy dynamics. This paper focuses on simulating CSR effects in conjunction with the shielding effect from parallel plates, which are crucial in mitigating potential beam energy loss.* By benchmarking results against Saldin's established work **, the study examines wakefield characteristics, particularly the high-peak behavior at small particle separations.
Paper: WEPM071
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPM071
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 05 Nov 2025
WEPM090
The stability diagram for longitudinal coupled instabilities of the ALBA upgrade
2180
The design of the ALBA upgrade forsees the use of an active harmonic cavity system for bunch lengthening. The resulting RF-potential will be a combination of a harmonic and a quartic potential. The corresponding stability diagram will be computed and compared to the stability diagram based on a pure quartic RF-potential. It will be checked if an already existing HOM in the DAMPY cavities and a parasitic mode found in the bellows can be damped with this mechanism. Since the radiation damping of the ALBA upgrade is rather weak the Landau damping is an asset for the stability of the upgrade.
Paper: WEPM090
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPM090
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025
WEPM094
Space charge in the GALACTIC Vlasov solver
2195
The GALACTIC Vlasov solver can be used to study the impedance-induced transverse coherent instabilities, considering any longitudinal distribution function, describing the beam with transverse coherent oscillation modes in the frequency domain and ending up with an eigenvalue system to solve. In this paper, the effect of the transverse coherent direct space charge is added, considering a linear RF force and three distribution functions in the longitudinal plane: Water-Bag (or uniform), Air-Bag (or Dirac delta) and Gaussian. These three cases are then compared to the Air-Bag bunch in a Square potential well (ABS) model, which has been often used in the past.
Paper: WEPM094
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPM094
About: Received: 21 May 2025 — Revised: 31 May 2025 — Accepted: 02 Jun 2025 — Issue date: 05 Nov 2025
WEPM098
Transverse mode-coupling instability with Landau cavities at the MAX IV laboratory 1.5 GeV ring
2203
Collective effects can have a strong influence on the beam stability and performance in synchrotron light sources. Landau cavities or RF harmonic cavities are a tool that is employed at 4th generation storage ring light sources to reduce the impact of or even prevent instabilities arising from collective effects. The positive effect of Landau cavities is based on the lengthening of the electron bunches and an increase in synchrotron tune spread. Recent theoretical calculations by M. Venturini (2018) predict however, that at zero chromaticity, the threshold current of the transverse mode-coupling instability (TMCI) was reduced in the presence of Landau cavities. This contribution presents measurements conducted at the MAX IV 1.5 GeV storage ring, where, to test the prediction, the TMCI threshold was measured with and without bunch-lengthening using passive Landau cavities. The effect at non-zero chromaticity was also investigated.
Paper: WEPM098
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPM098
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 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-IPAC2025-WEPM114
About: Received: 22 May 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 05 Nov 2025
WEPS007
Measurement of coherent synchrotron frequencies under conditions close to the Robinson limit at the Aichi Synchrotron Radiation Center
2248
Past measurements* of coherent synchrotron frequencies at the Photon Factory storage ring revealed that the behavior of measured coherent frequencies could not be well explained with standard 4th-order characteristic equation under conditions close to the Robinson limit. To investigate whether similar phenomenon occurs in other storage rings, we measured the coherent synchrotron frequencies at a 1.2-GeV electron storage ring of Aichi Synchrotron Radiation Center as a function of the cavity voltage and the beam current. At beam currents higher than about 200 mA, we observed double peaks, one with a frequency higher than the incoherent synchrotron frequency and one with a lower frequency, that can correspond to two independent solutions of the 4th-order characteristic equation. Our preliminary analysis indicated that the frequencies of lower-frequency peak did not agree well with those predicted by the characteristic equation. We also observed that under a condition very close to the Robinson limit, the beam exhibited strong longitudinal coherent self-excited oscillation without beam dump. We present these measurement results and updated analysis.
Paper: WEPS007
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPS007
About: Received: 27 May 2025 — Revised: 13 Oct 2025 — Accepted: 13 Oct 2025 — Issue date: 05 Nov 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-IPAC2025-WEPS028
About: Received: 27 May 2025 — Revised: 03 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 05 Nov 2025
WEPS047
Report on Opera-3D hands-on session in the 7th International School on Beam Dynamics and Accelerator Technology (ISBA24)
2345
The 7th International School on Beam Dynamics and Accelerator Technology (ISBA24) held in Chiangmai University during November 1-9, 2024, encompasses seven days opportunities where the foundation of accelerator physics is applied during hands-on sessions with simulation software including ASTRA, ELEGANT, Opera-3D and CST Studio Suite. Opera-3D, a finite element-based Maxwell’s equations solver, is known for its powerful low frequency simulation capabilities and is appropriate for magnet design. Instructed by two lecturers from Synchrotron Light Research Institute, 15 students from China, Japan, India and Thailand were trained on the Opera-3D software fundamentals in the application of magnet design for particle accelerator. The students showcase their knowledge in the group assignments including the design of H-shape dipole, C-shape dipole and combined horizontal and vertical corrector with success. Thanks to the generous support of the ISBA24 sponsors and Sigma Solutions Co., Ltd., who provided the software licenses during the school. This article reports on the completion of the ISBA24 Opera-3D hands-on session provided to graduate students and young researchers from the Asian region.
Paper: WEPS047
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPS047
About: Received: 18 May 2025 — Revised: 30 May 2025 — Accepted: 31 May 2025 — Issue date: 05 Nov 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-IPAC2025-WEPS048
About: Received: 28 May 2025 — Revised: 30 May 2025 — Accepted: 30 May 2025 — Issue date: 05 Nov 2025
WEPS063
Estimation of coupled-bunch instability induced by high-order modes of bell-shaped cavity in high current operation at SPring-8-II
2373
At the large synchrotron radiation facility SPring-8, the upgrade project “SPring-8-II” is underway to increase the radiation brightness by 100 times. In SPring-8-II, the beam energy will be reduced from 8 GeV to 6 GeV and the beam current will increase from 100 mA to 200 mA. The bell-shaped 509 MHz cavities will remain in place at SPring-8-II, with the number of cavities reduced from 32 to 16. Currently, the longitudinal coupled-bunch instability (CBI) is not observed. However, the CBI may occur due to high-order modes (HOMs) in some cavities because of the parameter changing at SPring-8-II. We estimated the threshold shunt impedance and Q-value for the CBI by using Ansys HFSS. Especially, TM011 mode at 900 MHz has a large impedance and the threshold impedance is 0.8 MΩ, which corresponds to QL~12,000 when R/Q=65Ω. On the other hand, we measured the actual QL-value of the cavities using single-bunch beam. The spectra and its Q-values of the HOM induced by the beam were measured. The results show that most cavities are below the threshold, but some cavities are over threshold. If the HOM causes instability, we plan to adjust two tuner plungers to shift them off the peak.
Paper: WEPS063
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPS063
About: Received: 30 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 05 Nov 2025
WEPS076
Thresholds of longitudinal multi-bunch instabilities in double harmonic RF systems
2398
Multi-bunch instabilities, often driven by narrowband impedance sources such as higher-order modes, present significant intensity limitations in synchrotrons. One approach to mitigate these instabilities is applying a double harmonic radio frequency (RF) system, which can increase the intensity threshold by enlarging the synchrotron frequency spread. In this study, intensity thresholds are calculated for different RF parameters using stability diagrams derived from the Lebedev equation. We analysed configurations and beam characteristics relevant to the synchrotrons at CERN, particularly focusing on the Super Proton Synchrotron (SPS). The semi-analytical results were then compared to macroparticle simulations and measurements. The findings reveal an unexpected beam stabilisation even if a non-monotonic amplitude dependency of the synchrotron frequency is present. Further, techniques for deducing the driving impedance parameters are discussed.
Paper: WEPS076
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPS076
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 05 Nov 2025
THPB004
Development of residual gas analyzer measurement system capable of operating in the 10 Torr vacuum range
2507
Residual Gas Analyzers (RGA) are widely used to mon-itor gas composition in vacuum systems. However, they are typically limited to high-vacuum environments and cannot be used directly in processes that operate at higher pressures. To solve this problem, we developed a modular and easy-to-build differential pumping system that allows an RGA to monitor vacuum environments up to 10 Torr. In this study, we present the design of this system. Thanks to its modular design, the system can be easily extended to operate at higher working pressures by adding more modules.
Paper: THPB004
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPB004
About: Received: 26 May 2025 — Revised: 02 Jun 2025 — Accepted: 13 Oct 2025 — Issue date: 05 Nov 2025
THPB005
Surface characterization of vacuum chambers with synchrotron radiation exposure at a beamline
2510
Exposure of synchrotron radiation on the vacuum chambers induces high yield of photoelectrons and the consequent increase of pressure from stimulated gas desorption. Characterization of the surface quality of vacuum chambers, either after chemical cleaning or with thin film coating, by synchrotron radiation exposure at a beamline is powerful and sensitive. In this study, analysis of photo-desorption and photoelectron yield for various vacuum chambers, metallic tubes with or without NEG-coatings, at the BL19B-beamline of Taiwan Light Source (TLS) with critical photon energy of 2.14 keV will be described and compared.
Paper: THPB005
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPB005
About: Received: 28 May 2025 — Revised: 31 May 2025 — Accepted: 31 May 2025 — Issue date: 05 Nov 2025
THPB006
Improvement of PLS-II Photon Absorbers
2513
In synchrotron accelerators, managing the intense photon flux generated by bending magnets is very important for maintaining the accelerator's performance. The emitted synchrotron radiation, characterized by its high intensity and broad spectrum, imposes significant thermal and structural demands on accelerator components. Photon absorbers are essential to effectively block excess photons, ensuring stable operation and extending the lifespan of the vacuum components. In this poster, I would like to introduce the new shape and analysis results to improve the performance of the vertical-type photon absorbers operating in PLS-II.
Paper: THPB006
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPB006
About: Received: 28 May 2025 — Revised: 13 Oct 2025 — Accepted: 13 Oct 2025 — Issue date: 05 Nov 2025
THPB023
Numerical simulation of a modified air conditioning system of the experimental hall at TPS
2552
Taiwan Photon Source (TPS) has been committed to serve users for eight years. In the first and second phases of TPS beamline project, there were 16 beamlines had been in operation. The third phase project had been launched in 2021. Facing the more persons and equip-ment in the experimental hall as well as power saving issue, we applied the computational fluid dynamic (CFD) scheme to simulate the air conditioning system to obtain better cooling efficiency. We modelled one twelfth of the TPS experimental hall and two beamlines.
Paper: THPB023
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPB023
About: Received: 28 May 2025 — Revised: 30 May 2025 — Accepted: 13 Oct 2025 — Issue date: 05 Nov 2025
THPB024
Network system upgrade and information security management system implementation at NSRRC
2555
With the advancement of science and technology, people are more dependent on the Internet and digital technology. We continue to improve our network system to increase speed and security of information transmission at NSRRC. We had established various levels of Information Security System (ISMS) documents and conducted many tasks and obtained the certification of ISO-27001.
Paper: THPB024
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPB024
About: Received: 28 May 2025 — Revised: 14 Oct 2025 — Accepted: 14 Oct 2025 — Issue date: 05 Nov 2025
THPB025
Power quality measurement and analysis for grid-connected rooftop photovoltaic systems at NSRRC
2558
NSRRC started its solar energy systems installation project in 2016 and began construction in early 2017. Solar modules have been gradually planned and installed on the rooftops of office, laboratory, and Utility buildings. The total installed capacity has now accumulated nearly 1.2MWp, and the total electricity generated to date has reached 10.8GWh, with a total carbon reduction of 5.7kt. This article will analyze and discuss various monitoring data (including voltage/current imbalance rate, harmonic distortion, active power, power factor, etc.) measured during the operation of the solar energy generation system in parallel with the power grid.
Paper: THPB025
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPB025
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 14 Jun 2025 — Issue date: 05 Nov 2025
THPB026
Utility design of the 3 GeV electron storage ring for Siam Photon Source II
2561
The Siam Photon Source II (SPS-II) is a new synchrotron light source currently under development in Thailand. Its 3 GeV electron storage ring features a lattice composed of 14 Double Triple Bend Achromat (DTBA) cells, with a total circumference of 327.6 meters. To ensure beam stability and operational reliability, a comprehensive suite of utility systems is required. The design incorporates critical infrastructure, including the electrical power system, deionized (DI) water system, air conditioning system, and compressed air system. These utilities provide essential support to both accelerator and beamline subsystems, such as magnets and power supplies, RF cavities and power supplies, vacuum chambers, insertion devices, front-end components, and experimental beamlines. This paper focuses on design considerations for the stability of the electrical power systems and the temperature regulation of the DI water and air conditioning systems. The electrical power demands and cooling loads are estimated based on the specific operational requirements of each accelerator subsystem.
Paper: THPB026
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPB026
About: Received: 28 May 2025 — Revised: 31 May 2025 — Accepted: 14 Oct 2025 — Issue date: 05 Nov 2025
THPB030
CFD thermal studies of the air inside the storage ring tunnel of the ALBA synchrotron light source for the 3rd and 4th generation designs
2576
The ALBA Synchrotron is currently designing its new version to become a 4th generation particle accelerator. In this new scenario, ALBA would produce a brighter and more coherent photon beam. As a result, ALBA would provide capabilities hitherto inaccessible in terms of resolution, detection levels and understanding of chemical and electromagnetic properties. In this context, the thermal and geometric conditions inside the tunnel will be modified, specifically the Storage Ring. The Booster Ring, Transfer Lines, Air Conditioning System and the tunnel itself will not be modified. The prediction of the thermal behaviour of the air inside the tunnel for the 4th generation is essential, considering the influence of the stability of the air temperature on the stability of the electron beam orbit. The present work assesses Computational Fluid Dynamics (CFD) studies of the air inside both the current and the 4th generation ALBA tunnel. Comparative studies of the temperature distribution in the air are performed and proposals for the optimization of the air conditioning system are presented. The studies are based on the FLUENT software of ANSYS WORKBENCH.
Paper: THPB030
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPB030
About: Received: 22 May 2025 — Revised: 03 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 05 Nov 2025
THPB031
Experimental studies of thermal contact conductance between copper, stainless steel and aluminum samples using a setup developed at ALBA Synchrotron Light Source
2580
Accurate knowledge of the Thermal Contact Conductance (TCC) between surfaces is of great importance for the design of components in particle accelerators, such as mirrors, monochromators, filters, detectors, among others. The TCC depends on many variables such as surface finish, type of material, pressure between samples, temperature and interface materials. The TCC can be found in specialized literature, but it is not always possible to find this information for all applications. This forces the design engineer to assume conservative or optimistic values that can result in over or under sized designs. In this context, an experimental setup has been developed in the Engineering Division of ALBA to evaluate thermal contacts under ambient and cryogenics conditions, in vacuum and for different pressure ranges between samples. This work presents the latest experimental results obtained for sample combinations of Copper, Stainless Steel and Aluminium materials.
Paper: THPB031
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPB031
About: Received: 23 May 2025 — Revised: 14 Oct 2025 — Accepted: 14 Oct 2025 — Issue date: 05 Nov 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-IPAC2025-THPB047
About: Received: 27 May 2025 — Revised: 14 Oct 2025 — Accepted: 14 Oct 2025 — Issue date: 05 Nov 2025
THPB060
Mechanical design and challenges of the FCCee arc radiation shielding
2638
The FCC-ee faces challenges in managing radiation from primary synchrotron photons, which can damage machine components and tunnel equipment due to cumulative exposure. Effective shielding is crucial to reduce equipment failure, prevent performance degradation, and limit reliance on costly radiation-hard materials. The proposed solution involves enclosing photon stoppers with shielding inserts and plates. With 2580 dipoles, each containing 10 photon stoppers, the machine requires shielding for 25800 stoppers. A preliminary lead-based design shows promise in dose reduction, but optimization is needed to control costs, meet integration constraints, and ensure manufacturing feasibility. Current estimates suggest each stopper will require 400 kg of shielding, totaling 10320 tons of lead. Optimization focuses on refining the shielding’s shape, size, and materials, while simplifying fabrication and installation to improve scalability. Goals include detailed cost estimates, spatial assessments, and a design addressing thermal management, mechanical integrity, and structural support, ensuring significant reduction of ionizing dose. This work is vital for proving the FCC’s feasibility.
Paper: THPB060
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPB060
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 05 Nov 2025
THPB061
MEDSI 2025: Celebrating 25 years of innovation in synchrotron engineering
2642
The 13th International Conference on Mechanical Engineering Design of Synchrotron Radiation Equipment and Instrumentation (MEDSI 2025) marks the 25th anniversary since the first MEDSI workshop in 2000. This biennial meeting, hosted by MAX IV Laboratory in Lund, Sweden, from September 15–19, 2025, is expected to welcome over 300 delegates and more than 30 industrial exhibitors. MEDSI is the leading forum for advancing engineering in synchrotron and free-electron laser (XFEL) facilities, featuring sessions on precision mechanics, photon delivery, simulation, and core technology developments. MEDSI 2025 will also introduce a special session on neutron source instrumentation, emphasizing collaboration with the European Spallation Source (ESS). The event includes invited and contributed talks, poster sessions, and an industrial exhibition, with all contributions published in the JACoW Proceedings. For more information, visit www.medsi2025.com.
Paper: THPB061
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPB061
About: Received: 19 May 2025 — Revised: 29 May 2025 — Accepted: 29 May 2025 — Issue date: 05 Nov 2025
THPB079
Investigation of properties of CuZr alloy for vacuum chamber structural materials
2644
CuZr alloy is considered for the structural material of the vacuum chamber of the Hefei Advanced Light Facility (HALF) storage ring. We tested the outgassing rate of CuZr material. The outgassing rate of CuZr alloy can reach 4.93×10^-11 Pa·L/s·cm² after baking at 180°C for 48h, which is more than one order of magnitude lower than that of SS. These results indicate that CuZr alloy is easier to degas by baking at lower temperatures and is a material with very low outgassing rates. At the same time, it is a highly competitive structural material for future accelerator vacuum chamber based on its good electrical conductivity, high strength and hardness.
Paper: THPB079
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPB079
About: Received: 17 May 2025 — Revised: 14 Oct 2025 — Accepted: 14 Oct 2025 — Issue date: 05 Nov 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-IPAC2025-THPB101
About: Received: 23 May 2025 — Revised: 02 Jun 2025 — Accepted: 06 Jun 2025 — Issue date: 05 Nov 2025
THPM009
Model-based optimisation for automated multi-turn extraction tuning at the CERN Proton Synchrotron
2703
Multi-Turn Extraction (MTE) is a resonance-based technique employed in the CERN Proton Synchrotron (PS) to split the beam in horizontal phase space before extraction to the Super Proton Synchrotron (SPS). The splitting efficiency is evaluated based on the uniformity of intensities across the beamlets, requiring fine-tuning of multiple parameters. In this paper, we investigate the influence of key parameters on MTE efficiency to improve the understanding of their impact on the process. Using a Gaussian Process model and various visualization techniques, we assess the sensitivity of the MTE efficiency to horizontal tune, transverse feedback gain, excitation frequency, beam intensity and magnetic hysteresis. Results from experiments and simulations indicate a complex, non-convex relationship between MTE performance and the parameters listed above. Additionally, external factors such as thermal fluctuations may contribute to performance variability. Our findings highlight the need for a model-based controller to counteract parameter drift, thereby ensuring consistent MTE beam quality during operation. We propose a solution supported by experimental results.
Paper: THPM009
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPM009
About: Received: 26 May 2025 — Revised: 30 May 2025 — Accepted: 01 Jun 2025 — Issue date: 05 Nov 2025
THPM071
Synchronous phase measurement and study at the Taiwan Photon Source
2835
A bunch-by-bunch synchrotron phase detector system has been implemented to investigate the synchronous phase behavior of the storage ring at the Taiwan Photon Source. This detector employs I/Q demodulation to cal-culate the beam phase on a bunch-by-bunch basis. The acquired data is integrated into the accelerator control system, visualized through a graphical user interface, and made available for further analysis. Independent component analysis (ICA) is employed to identify under-lying sources. For a trapezoid-like filling pattern, transi-ent beam loading effects are clearly observed in the flat-top region, whereas significant phase variations occur along the sloped edges of the pattern. During the beam decay period, an in-phase synchrotron phase oscillation at 7 kHz is observed, which originates from the rotation frequency of the radio-frequency transmitter. During injection, three distinct modes are identified through ICA decomposition. Among them, the amplitude of the syn-chronous oscillation mode shows a strong dependence on the injected bucket address.
Paper: THPM071
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPM071
About: Received: 20 Apr 2025 — Revised: 30 May 2025 — Accepted: 31 May 2025 — Issue date: 05 Nov 2025
THPM072
The online emittance monitor at Taiwan Photon Source
2839
This study summarizes the X-ray pinhole camera results from two recently constructed diagnostic beamlines. We provide updated emittance and energy spread measurements for the TPS storage ring and implement online measurements for routine operational monitoring.
Paper: THPM072
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPM072
About: Received: 19 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025
THPM073
The Issue with XBPM2 in the TPS Front End
2842
Two sets of blade-type beam position monitors (XBPMs) are installed in the Taiwan Photon Source (TPS) front-end. The upstream XBPM, referred to as XBPM1, has been calibrated and can calculate the photon beam center position. The downstream XBPM, referred to as XBPM2, encountered difficulties during calibration. It was unable to obtain an effective linear range. Adjustments to the blade spacing and alternative calibration methods were explored to address this issue. These details will be discussed in the article.
Paper: THPM073
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPM073
About: Received: 23 May 2025 — Revised: 14 Oct 2025 — Accepted: 14 Oct 2025 — Issue date: 05 Nov 2025
THPM075
The efforts on beam stability improvement in TPS
2845
This report discusses various efforts to improve beam stability at the Taiwan Photon Source. The Fast Orbit Feedback (FOFB) system is essential for maintaining beam stability in the light source. Considering the trade-off between FOFB reliability and performance, we optimize the FOFB parameters to achieve better orbit stability in the TPS. Occasional spikes in the Beam Position Monitor (BPM) readings are observed in a few BPM pick-ups and it would degrade the efficiency of the FOFB system. The probability of these spikes occurrence could be related to the different filling patterns and beam currents. A schedule for replacing these BPM buttons will be established. Additionally, the effect of various signal processing schemes on the beam is also examined.
Paper: THPM075
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPM075
About: Received: 27 May 2025 — Revised: 14 Oct 2025 — Accepted: 14 Oct 2025 — Issue date: 05 Nov 2025
THPM086
Improvement of transverse beam size measurement using synchrotron radiation at Siam Photon Source
2859
The Siam Photon Source (SPS) has, for several decades, implemented direct imaging with synchrotron radiation for the measurement of transverse beam size. This paper describes improvements made to the transverse beam measurement system of the SPS storage ring. A synchrotron radiation interferometer system will be integrated for monitoring of beam size alongside the direct imaging system. The system's operations will be controlled and displayed through Python programming. The results from each technique will be comparatively analyzed.
Paper: THPM086
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPM086
About: Received: 28 May 2025 — Revised: 30 May 2025 — Accepted: 31 May 2025 — Issue date: 05 Nov 2025
THPS010
On-line estimation approach to fault-tolerant control of orbit stability at Siam Photon Source
2964
A novel approach combining online unknown input estimation with reconfigurable control has been developed to enhance orbit stability in the Siam Photon Source (SPS) storage ring. These unknown inputs, representing disturbances or uncertainties in the dynamic system, provide valuable insights for achieving robust control. Disturbances such as noise, temperature changes, and modeling uncertainties affecting the control variables can be treated as fault signals, allowing the application of fault estimation and compensation techniques from Fault Diagnosis (FD) and Fault-Tolerant Control (FTC) theories. The initial implementation of this slow orbit feedback (SOFB) system has significantly reduced X-Y orbit fluctuations while maintaining robust control stability against temperature disturbances in the SPS storage ring. This presentation will cover the FD/FTC principles, hardware, software, commissioning results of the current SOFB system, and plans for future developments.
Paper: THPS010
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPS010
About: Received: 21 May 2025 — Revised: 14 Oct 2025 — Accepted: 14 Oct 2025 — Issue date: 05 Nov 2025
THPS060
Photon stimulated desorption from cryogenic surfaces of high temperature superconductor and amorphous carbon thin films
3101
High Temperature Superconductor (HTS) and amorphous Carbon (a-C) thin films, and their combination, are being considered as possible surface coatings for the FCC-hh beam screen (BS) with the aims of reduction of the resistive wall impedance and mitigation of the electron cloud. Along with these required properties, i.e., the high electron conductivity and low secondary electron yield, the Photon Stimulated Desorption (PSD) yield is one of the most essential characteristics in the design and operation of the FCC-hh vacuum systems. For this purpose, a series of the PSD measurements is currently conducted at a dedicated beamline in the KEK Photon Factory, where similar conditions to FCC-hh in terms of the Synchrotron Radiation energies and power density are available. In order to realize a similar cryogenic condition of the BS (40-60 K), the sample container is equipped with a LN2 jacket (77 K) and installed in an insulation vacuum chamber. The conditioning behaviors of the PSD yields as a function of the photon dose are being obtained for uncoated copper and HTS, and a-C coated copper and HTS, and each sample is examined at cryogenic and room temperatures for comparative analysis.
Paper: THPS060
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPS060
About: Received: 31 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 05 Nov 2025
THPS073
Developing an Object Detector Using Synthetic Data from CAD Models
3117
This work investigates the potential of using synthetic images generated from CAD models to train an object detector for identifying components of a particle accelerator. The study focuses on magnets within the new ALS Accumulator Ring at Lawrence Berkeley National Laboratory. Generating large volumes of real-world training data is often challenging in such complex systems. To address this, CAD files were converted into 3D models and used to produce diverse synthetic datasets. These datasets were augmented with a smaller set of real-world images to train a YOLOv8-based model. This approach aims to evaluate whether synthetic images can effectively support the development of object detectors in environments where real data collection is limited. The study lays the groundwork for future development of real-time recognition tools to assist accelerator operations.
Paper: THPS073
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPS073
About: Received: 28 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025