distributed
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
MOPB063
Spatial polarization distribution measurements of gamma rays produced by inverse Compton scattering
194
Highly polarized MeV gamma rays, produced by Laser Compton Scattered (LCS) of a polarized laser with an electron beam, offer a unique probe for basic and applied physics research. As the polarization characteristics of these gamma rays vary with the position of the beam cross section, it is essential to understand the polarization properties when using polarized gamma rays * . However, detailed measurements of the two-dimensional spatial polarization distribution have not yet been conducted. In the UVSOR synchrotron facility, a polarimeter was developed to measure the spatial polarization distribution of linearly polarized gamma rays. The polarimeter is based on asymmetry measurements of the Compton scattering cross section. In this conference, we will report on measurement results of the spatial polarization distribution of linearly and circularly polarized LCS gamma-rays. The polarization axis of the polarized gamma rays was clearly measured to vary with scattering and azimuth angle. In the near future, we plan to use the developed polarimeter to also measure the spatial polarization distribution of gamma rays generated by an axially symmetric polarized laser ** .
Paper: MOPB063
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPB063
About: Received: 28 May 2025 — Revised: 01 Jun 2025 — Accepted: 01 Jun 2025 — Issue date: 05 Nov 2025
MOPB108
Coherent undulator radiation with account of the beam energy spread
254
When a microbunched beam is sent to a resonantly tuned undulator it radiates coherent radiation with the intensity propotional to the bunching squared of the beam. According to *, the radiated energy increases with the undulator length. This conclusion, however, is only valid if one ignores the energy spread of the beam (and also the beam angular spread). The finite energy spread smears the microbunching, ultimately suppressing coherent radiation beyond a certain distance. In this work, we calculate the radiation of a microbunced beam with an energy spread and find the maximum energy that it can radiate coherently.
Paper: MOPB108
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPB108
About: Received: 22 May 2025 — Revised: 30 May 2025 — Accepted: 03 Jun 2025 — Issue date: 05 Nov 2025
MOPM017
Do transverse bunch tails produce luminosity?
314
Heavily populated transverse beam tails can be an issue for the operation and the performance of present and future particle colliders. In this respect, the tailoring of beam distributions through transverse halo scraping is a powerful technique for limiting beam losses and maximizing beam lifetime. By doing so, a portion of the bunch intensity is sacrificed, to the benefit of a reduced bunch transverse emittance. In this paper, we assess the impact on the luminosity performance of the LHC using such bunches, based on an analytical approach supported by numerical integration. In particular, we quantify the interplay between beam scraping, bunch intensity loss, transverse emittance reduction and collider luminosity performance.
Paper: MOPM017
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPM017
About: Received: 26 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025
MOPM023
Damage potential and machine protection criticality of the FCC-ee beams
338
The lepton beams of the Future Circular Collider FCC-ee will store 17.5 MJ of energy per beam during Z mode operation. The damage potential of these beams is an essential input for the design of the machine protection system. In this paper, first, the stored energy and energy density of the FCC-ee beams are reported and compared with the values for the Large Hadron Collider (LHC) and the High-Luminosity LHC (HL-LHC). Then, results of energy deposition studies using FLUKA for the generic scenario of a direct beam impact on graphite are presented. Due to the small beam sizes and the distinct shower development, the FCC-ee beams cause peak energy depositions that for Z mode intensities can be comparable to the LHC proton beams. In a last step, the initial hydrodynamic response of the material is simulated using ANSYS Autodyn for a round beam featuring an equivalent peak energy deposition. The calculated temperature rise and density depletion are presented and discussed.
Paper: MOPM023
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPM023
About: Received: 28 May 2025 — Revised: 30 May 2025 — Accepted: 30 May 2025 — Issue date: 05 Nov 2025
MOPM043
Comparison of particle in cell and soft-Gaussian beam-beam solvers
414
A crucial component for designing particle colliders is the assessment of beam-beam effects at collisions. Particle In Cell (PIC) solvers are popular numerical tools, which solve the Poisson equation for the electromagnetic (EM) potential $\Phi$ produced by the colliding beam's bunches spread on a discretized grid, and compute the Lorentz force acting on the particles subjected to the gradient of $\Phi$. The main limitation of this approach is the high computational cost, which can be alleviated at the expense of accuracy by using approximation techniques, such as the soft-Gaussian approximation, which assumes the bunch particles to have transverse Gaussian distributions. Both methods are widely used in the accelerator physics community. The Xsuite framework is the first multiparticle tracking tool, which aims to support both approaches. This contribution compares the performance of their Xsuite implementation.
Paper: MOPM043
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPM043
About: Received: 24 May 2025 — Revised: 02 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
MOPM050
Combining quadrupole-driven slow extraction with RFKO at the CERN SPS
441
The CERN Super Proton Synchrotron (SPS) employs quadrupole-driven third-integer slow extraction to deliver beam to the North Area. This process is controlled by ramping all the magnets in the lattice, gradually driving the circulating beam into the tune resonance. In medical synchrotrons, Radio-Frequency Knock Out (RFKO) has proven to be a reliable alternative for driving the extraction process while maintaining good spill quality. Inspired by these efforts, a hybrid scheme was tested in the SPS, where a transverse exciter was used to apply a sinusoidal excitation in parallel with the magnetic ramp. It is demonstrated that this setup improves spill uniformity both in simulation and measurements.
Paper: MOPM050
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPM050
About: Received: 26 May 2025 — Revised: 30 May 2025 — Accepted: 01 Jun 2025 — Issue date: 05 Nov 2025
MOPM063
Collimator damage study for the Diamond-II storage ring
462
To understand the risk of damage to the collimator blades and the permanent magnets in Diamond-II, the BDSIM code has been used to model the beam losses. To improve the accuracy, the engineering model and 3D field maps have been used to build the machine model. Energy deposition in the main storage ring components and the fluence of secondary particles (particularly neutrons) have been determined. This paper explains the simulation process and give the BDSIM tracking results.
Paper: MOPM063
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPM063
About: Received: 27 May 2025 — Revised: 02 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 05 Nov 2025
MOPM080
Optimisation of drift tube cooling and drift tube geometries of an additive manufacturing IH-type cavity
510
Additive manufacturing is a now-powerful tool for the rapid prototyping and manufacturing of complex geometries. A proof-of-concept 433 MHz IH-DTL cavity was constructed for direct additive manufacturing of linear accelerator components. The CFD analysis of the initially designed cooling for the drift tube revealed a design with insufficient heat dissipation; this can lead to thermal deformations as well as problems in keeping the frequency stable during operation. In this respect, an optimization of the cooling system was done in detail with the help of advanced thermal simulation and iterative design improvements. Furthermore, the geometries of the drift tubes were refined to improve mechanical stability and thermal efficiency without compromising electromagnetic performance. The results illustrate that additive manufacturing can achieve significant design freedom, enabling new approaches toward the thermal management challenges faced by high-frequency linear accelerator components.
Paper: MOPM080
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPM080
About: Received: 28 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025
MOPM093
Positron contamination in the muon beam at the J-PARC's surface muon beamline (S-line)
542
The surface muon beamline at J-PARC provides high-intensity muon beams that are essential for advanced materials science research, particularly in techniques such as muon spin rotation/relaxation (μSR). However, positron contamination in the beam poses a significant challenge by introducing background noise that affects the measurement precision. Therefore, achieving high-purity muon beams is critical for improving experimental reliability and accuracy. In this study, the G4beamline Monte Carlo simulation toolkit was employed to model the transport of muons and positrons from the production target through the beamline. The system includes a momentum and charge-based separator followed by a collimating slit. While the current slit configuration effectively suppresses positrons, it also causes substantial muon loss of approximately 76%, which significantly reduces the usable muon flux for downstream applications. To address this issue, a detailed investigation into slit size was performed. The results indicate that modest adjustments to the slit aperture size can improve the muon-to-positron ratio while retaining a greater fraction of the muon beam. These results provide valuable guidance for optimizing beamline performance and improving the quality of muon-based experiments at J-PARC.
Paper: MOPM093
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPM093
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025
MOPS004
Longitudinal hollow electron beam
588
The intra-beam scattering in high charge state intense heavy ion beams is a problem worth considering. With the help of controlling the longitudinal distribution of the ion beam, it may be possible to alleviate the ion beam loss and to improve the ion beam lifetime caused by intra-beam scattering. Unlike the traditional cooling process of direct current electron beams or longitudinal uniform distribution electron beams, a longitudinal hollow electron beam is used to cool heavy ion beams. Ions at the edge of the ion beam will receive stronger cooling, while ions at the center of the ion beam will receive weaker cooling, avoiding overcooling at the center of the ion beam. This paper discusses the generation, measurement, and related issues of longitudinal hollow electron beams. Corresponding solutions and suggestions have been proposed for the problems and challenges that may be encountered in the research. The cooling process of longitudinal hollow electron beams will be simulated and experimentally studied in the further, with the hope of obtaining beneficial effects.
Paper: MOPS004
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPS004
About: Received: 09 May 2025 — Revised: 30 May 2025 — Accepted: 08 Oct 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
MOPS006
The Vaccaro stability diagram of scaling FFAs
596
Fixed Field Accelerators (FFAs) are a promising candidate for future high intensity machines such as ISIS-II. It follows that the largely unexplored topic of coherent transverse beam instabilities in these machines is of increasing importance. Transverse instabilities, such as head-tail, can be mitigated in synchrotrons by adjusting the chromaticity appropriately. However, in scaling FFAs, the chromaticity is fixed at zero by design. On the other hand, the relatively strong tune shift with amplitude caused by the nonlinear field of FFA magnets provides a source of Landau damping. Here we evaluate the resulting stability region in the complex tune shift plane comparing an analytical prediction based on the extracted detuning with amplitude with the results from numerical tracking simulations. Hence, the impedance threshold of FFAs can be established.
Paper: MOPS006
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPS006
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025
TUAN2
No parametric instabilities in actual linear accelerators except the envelope instability
870
Our studies indicate that parametric instabilities except the envelope instability are unlikely to be observed in actual linear accelerators unless waterbag or KV distributions are generated. Furthermore our studies and previous literatures indicate the dominance of particle resonances over parametric instabilities in high-intensity linear accelerators. Any counter evidence has not been found yet. We propose a way to overcome the previous design rule to avoid the zero-current phase advance > 90° for the high-intensity linac.
Paper: TUAN2
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUAN2
About: Received: 15 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025
TUCD3
Evaluation method and countermeasures for the beam loss in fourth-generation light sources
919
Unlike the situation under the third-generation light sources, we will have to pay more attention to control electron beam loss under the fourth-generation ones. The main causes of the beam loss are (i) a beam dumped by switching off RF cavities and (ii) electrons lost by electron-electron scattering (the Touschek effect). Due to the low emittance, if the highly-dense dumped beam directly hits a chamber, that will induce a vacuum accident. Due to the short beam lifetime, the number of scattered electrons hitting insertion devices (IDs) increases, and demagnetization would severely shorten the ID lifetime to be less than 10 years. Here we evaluate and elucidate how a dumped beam and scattered electrons are lost in the storage ring. To investigate the process of Touschek loss, we developed an analytical method following Piwinski’s formulation and calculated the spatial and energy distributions along the ring. Taking SPring-8-II as an example, our calculation indicates that a beam shaker is effective to reduce beam power density, and the installation of vertical scrapers in the long straight sections and shielding materials in the IDs can prevent the component damage of the ring.
Paper: TUCD3
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUCD3
About: Received: 28 May 2025 — Revised: 01 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 05 Nov 2025
TUPB002
Consideration for improving the longitudinal beam matching between RCS and MR at the J-PARC
932
The J-PARC 3 GeV Rapid-Cycling Synchrotron (RCS) delivers the high-intensity proton beam to the 30 GeV Main Ring (MR). The improvement of longitudinal beam matching between RCS and MR is desired to suppress the beam loss in the MR. A scenario to improve the longitudinal beam matching between RCS and MR is designed. For the RCS, the bunch lengthening scheme using the unstable fixed point generated by the second harmonic is considered. For the MR, the RF voltage pattern is adjusted to match the longitudinal beam emittance of the RCS. The details of the scenario for improving the longitudinal beam matching between RCS and MR and the results of beam simulation studies are reported.
Paper: TUPB002
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPB002
About: Received: 26 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 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
TUPB018
Towards tailored beam distributions for fixed target experiments at CERN
987
The time-of-flight (nTOF) facility at CERN uses neutrons produced by a proton beam interacting with a fixed target. To prevent target damage, an upper bound on the peak energy density has been imposed. Adhering to this constraint requires a large beam size. Similarly, at CERN’s North Area, a large beam size is required at the septa splitting the beam towards different experiments. However, both cases suffer from limitations associated to losses of the primary beam, leading to poor transmission efficiency and high radioactive activation. This paper proposes an alternative approach by manipulating the beam distribution. Given the absence of strong nonlinear elements in both transfer lines, the focus shifts to tailoring the distribution before extraction. Particle tracking simulations are presented alongside experimental results, characterizing the phase space distribution as a function of machine parameters. Advanced deep learning methods that enable efficient exploration of the parameter space are also discussed.
Paper: TUPB018
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPB018
About: Received: 27 May 2025 — Revised: 30 May 2025 — Accepted: 30 May 2025 — Issue date: 05 Nov 2025
TUPB023
Simulation studies on bent silicon crystals for loss reduction in slow extraction operation at J-PARC Main Ring
1006
Reducing beam loss during slow extraction remains a critical challenge for the J-PARC Main Ring, which aims to enhance beam power for its 30 GeV proton beam. Since beam loss during slow extraction mainly occurs at the electrostatic septum, it is important to reduce beam loss at this location. Researchers at CERN SPS have recently reported that beam loss can be reduced by installing bent silicon crystals in the accelerator ring and utilizing their charged particle deflection effect. In this paper, we report the results of a simulation study on the expected beam loss reduction effect when the bent silicon crystal is installed upstream of the electrostatic septum of the J-PARC Main Ring and the beam deflection effects of the bent silicon crystal, called channeling or volume reflection, are utilized. The required size and installation position of the silicon crystal, and the required accuracy for adjusting the position and angle will also be reported.
Paper: TUPB023
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPB023
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025
TUPB031
Overview of seven-unit collimator system and its operation for J-PARC main ring
1037
The J-PARC main ring has three linear sections, and one have a beam collimator system downstream of the injection devices to localise beam losses. In September 2024, the seventh collimator unit was installed, completing an upgrade of the collimator system that has been underway since 2012. The system was changed from one that scatters and captures the beam halo to one that draws the jaw close to the beam core and directly removes its halo. This allowed a number of collimator units to be placed in a limited area. The original beam loss capacity in the collimator area was 450 W. Seven collimator units allow a beam loss of 3.5 kW. Currently, six collimator units are used to deliver 800 kW beams to neutrino experiments with losses of less than 500 W. By using seven collimator units, a beam of 1.3 MW can be delivered with a reasonable loss amount. The combination of units effectively removes the halo component of the beam and localises the beam losses. However, the direct removal method can create loss spots downstream of the collimator according to phase advance. This paper describes the operation of collimators in actual beam operation.
Paper: TUPB031
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPB031
About: Received: 29 May 2025 — Revised: 30 May 2025 — Accepted: 30 May 2025 — Issue date: 05 Nov 2025
TUPB032
Application of bayesian optimization in magnetic horn design
1040
Bayesian optimization is an effective method for designing complex systems with costly, non-analytic black box objective functions. It enables efficient exploration of the parameter space, making it well-suited for challenging problems in accelerator design which involve computationally intensive simulations such as FLUKA. This study presents a framework to apply Bayesian optimization techniques to design the magnetic horn of Neutrinos from Stored Muons (nuSTORM) experiment for increased pion capture. The optimization process spans a wide range of operational energies, from 1 to 7 GeV, to address the physics reach of nuSTORM. Batch sampling is enabled through specialized acquisition functions, allowing simulations to run in parallel across a computational cluster and significantly reducing the time needed to identify optimal target and horn configurations for the muon source. By leveraging the surrogate models generated through Bayesian optimization, horn configurations at different energies are systematically compared. This facilitates sensitivity studies to determine a minimal set of horn designs that efficiently cover the nuSTORM kinematic range.
Paper: TUPB032
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPB032
About: Received: 28 May 2025 — Revised: 01 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 05 Nov 2025
TUPB039
Design and optimization of a 3 GHz SCDTL for carbon ion acceleration in a medical injector
1053
Linear accelerators offer key advantages over circular machines in hadron therapy, such as rapid energy modulation and reduced activation. In this work, we optimized a 3~GHz Side-Coupled Drift Tube Linac (SCDTL) in terms of energy efficiency and the maximum achievable acceleration voltage. Comparative analyses were performed with alternative optimized configurations in TE and TM modes for ions with $\beta = 0.15-0.40$. The optimized structures were subsequently implemented in beam dynamics simulations for the energy upgrade of a carbon ion injector to be installed at the Instituto de Física Corpuscular in Valencia, Spain, achieving full transmission.
Paper: TUPB039
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPB039
About: Received: 28 May 2025 — Revised: 31 May 2025 — Accepted: 06 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
TUPB066
Design and calculation of the RF system of the U400R cyclotron
1113
Flerov Laboratory of Nuclear Reaction of Joint Institute for Nuclear Research carries out the works under creating of FLNR JINR Irradiation Facility based on the cyclotron U400R. The main systems of U400R are based on the U400 cyclotron. The objectives of this project are: - to increase the intensity of accelerated 48Ca ion beams from 1.2 puA to 2 puA; - to expand the energy range of accelerated ions from 2–20 MeV per unit mass to 0.8–25 MeV per unit mass; - to extract ion using stripping foil and deflector; - to reduce the energy spread in the beam to 3×10⁻³. The results of calculating the parameters of the new RF-system are given in this work.
Paper: TUPB066
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPB066
About: Received: 27 May 2025 — Revised: 02 Jun 2025 — Accepted: 13 Oct 2025 — Issue date: 05 Nov 2025
TUPM008
Six-dimensional phase space reconstruction with multimodal CNN
1182
The information on phase space in all six dimensions is required for various accelerator experiments. We developed an algorithm based on Convolutional Neural Network (CNN) that can be used instead of the traditional back projection techniques because it is less computationally intensive and has a simple architecture. Our method has shown consistency with the simulation, and we plan to validate it on data taken at the KEK–Superconducting Test Facility (STF).
Paper: TUPM008
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPM008
About: Received: 29 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025
TUPM045
Latest dark current studies of RF photocathode gun of Delhi Light Source
1252
The Delhi Light source is a pre-bunched Free Electron Laser facility to generate coherent THz radiation. The electron beam is generated from a normal conducting 2.6 cell RF photocathode (PC) gun operated at 2860 MHz. The RF gun is powered by a high power RF source for a duration of 4 µs at 10 Hz repetition rate. The dark current during the operation of the RF gun has been found to be substantially high with increasing forward powers (above 3 MW) even after prolonged RF conditioning. Dark current measurements has been done with an in-house developed faraday cup with an objective to understand the possible primary dark current source from locations at the PC that witnesses high accelerating fields. The measurements include the study of solenoid field variation to understand the dark current energies and effect of its steering to understand the possible dark current locations. Simulations to make inference from the measurements has been done assuming different radial position of dark current emitters at the PC surface. The details of the measurements, simulation results and the inference drawn are discussed in the paper.
Paper: TUPM045
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPM045
About: Received: 27 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025
TUPM076
Refined FLUKA simulation model of neutrino-induced effective dose from a multi-TeV muon collider
1329
Most muons injected into a muon collider decay into an electron (or positron) and a neutrino-antineutrino pair, producing a narrow disk of high-energy neutrinos emitted tangentially to the beam in the collider plane. These neutrinos reach the Earth’s surface at distances far away from the collider. Vertical diffusion of the neutrino cone, reducing integrated neutrino flux at any surface exit point, has been proposed as mitigation technique. This study presents effective dose calculations performed with the FLUKA Monte Carlo code for various geometrical models, each representing conservative radiation exposure scenarios from neutrino flux emerging from the ground at specific distances from muon decay points. These scenarios correspond to different parts of the muon collider ring: bending sections and long straight sections housing experiments. Results are provided as effective doses for annual exposure scenarios with a 100% occupancy. Two muon beam energies are considered: 1.5 TeV and 5 TeV, with a more detailed approach applied to the higher energy.
Paper: TUPM076
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPM076
About: Received: 27 May 2025 — Revised: 01 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025
TUPM092
Design studies on a kHz–MHz repetition rate pulsed muon source based on electron accelerator
1372
Certain types of muon experiments, such as muon spin rotation techniques and muon lifetime measurements, require beams with repetition rates around 50 kHz for optimal statistical performance. However, existing facilities are limited to pulsed beams operating at 25-50 Hz or continuous beams, both constrained by the time structure of proton drivers. Despite ongoing efforts to optimize these proton time structures, significant limitations in flexibility persist. This work introduces an alternative approach to muon production using high-repetition-rate (kHz-MHz) electron beams generated by superconducting linacs at XFEL facilities. This method provides unique temporal characteristics, promising substantial improvements in beam precision, flexibility, and experimental efficiency. We present comprehensive particle tracking simulations for the design of a surface muon beamline and detailed Monte Carlo studies to optimize target materials and geometries. The results underscore the potential of electron-driven muon sources to complement muon-based fundamental and applied physics research while extending the capabilities of current and future XFEL facilities.
Paper: TUPM092
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPM092
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 05 Nov 2025
TUPS051
Avoiding overcooled ion beams by exciting energy spread through electron cooling
1546
Ion accelerators use electron cooling to improve luminosity and beam lifetime. However, extremely low momentum spread in a cold beam weakens Landau damping, enabling the development of instabilities and potentially decreasing lifetime. To combat this, the NICA Booster electron cooling system allows to generate electron beams with oscillating energy to increase the momentum spread in ion beams. Here we describe the implementation of the energy oscillation technique and provide numerical calculations predicting the achievable momentum spread.
Paper: TUPS051
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPS051
About: Received: 27 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025
TUPS134
Improvement of electron beam properties for Few-TW LWFA conducted in a sub-mm gas cell filled with a helium-nitrogen mixture
1627
Developing a laser wakefield acceleration (LWFA) scheme by focusing few-TW laser pulses into a thin, dense gas target paves the way for generating high-average-current electron beams driven by a modern high-repetition-rate laser. Our previous study demonstrated that using a sub-mm nitrogen (N₂) gas cell facilitates the routine generation of 10-MeV-scale electron beams from few-TW LWFA with ionization-induced injection*. However, excessive ionization-induced defocusing of the pump laser pulse tends to occur in an N₂ target, motivating the use of a helium (He) – nitrogen (N₂) mixture as the gas target to mitigate pump pulse defocusing in few-TW LWFA**. In this study, the effect of nitrogen doping ratio ranging from 0.5% to 5% was investigated using 40-fs, 1-TW pulses with a 0.4-mm-long gas cell. We found that a manifest peak repeatedly appears around 10 MeV in the energy spectra with the 99.5% He - 0.5% N₂ gas mixture - a result never observed with the pure N₂ cell. Using the He-N₂ mixture also leads to a noticeable increase in the charge of high-energy electrons (>5 MeV) and a reduction in the pointing fluctuation of the output beams compared to the pure N₂ target.
Paper: TUPS134
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPS134
About: Received: 27 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025
TUPS152
Study on 200 MeV separated drift tube linac in Korea Multi-purpose Accelerator Complex
1644
Korea Multi-purpose Accelerator Complex (KOMAC) has been preparing 200 MeV energy upgrade. As a possible upgrade choice, separated drift tube linac (SDTL) type is considered in this study. From 2D analysis, optimum cell design deriving maximized effective shunt impedance and minimized Kilpatrick number is obtained. Then, final tank parameters considering stems, slug tuners, vacuum ports are determined under resonance frequency of 350 MHz. Based on that, 3D calculation is conducted to address electromagnetic and thermo-mechanical analysis. Electromagnetic mode and field flatness are analyzed by tuning slug tuners. In addition, appropriate cooling system is designed to minimize resonance frequency and electromagnetic structure variation.
Paper: TUPS152
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPS152
About: Received: 27 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025
WEPB015
Multicell parameterisation for sensitivity analysis and uncertainty quantification of elliptical accelerator cavities
1753
Elliptical cavity geometries are typically parameterised using a canonical set of variables that define the shape of the cavity half-cells. In multicell cavity optimisation, the mid-cells are modelled with identical dimensions, while the end-cells are optimised to ensure good field flatness. However, manufacturing tolerances can introduce slight variations between individual half-cells, as cavities are produced with separate dumb-bells, which are thereafter welded together. To address these variations, a multicell parameterisation is proposed, where each half-cell is defined by its own set of variables. This parameterisation method offers a more accurate representation of real-world cavity geometries and facilitates a detailed analysis of the impact of geometric uncertainties on cavity performance. A sensitivity analysis is presented to quantify the influence of each independent geometric variable on key performance metrics, providing valuable insights for optimising both cavity design and manufacturing processes.
Paper: WEPB015
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPB015
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 05 Nov 2025
WEPB022
Design and Implementation of a Power Monitoring and Distribution System for the SSPA-Based RF Transmitter at NSRRC
1775
This paper presents the design and implementation of a power distribution and monitoring system for a high-power RF solid-state amplifier (SSPA) system at the Taiwan Photon Source (TPS). The system consists of four SSPA towers delivering a combined RF power of 300 kW. Given efficiency and safety considerations, a robust distribution and protection architecture was implemented. The system features remote monitoring and control via a Modbus-connected PLC and HMI, enhancing reliability and operational insight.
Paper: WEPB022
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPB022
About: Received: 26 May 2025 — Revised: 02 Jun 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
WEPB084
Design of normal conducting quadrupoles for the spin rotator section in the EIC electron storage ring
1915
The interaction region IR6 in the Electron Storage Ring of the planned Electron Ion Collider facility at Brookhaven National Laboratory includes a section to rotate the electron spin into or out of the longitudinal direction. This section consists of superconducting solenoids, and normal conducting dipoles and quadrupoles. The geometry and field gradient requirements of the quadrupoles pose a challenge in their design with regards to yoke saturation and thereby field quality. Electromagnetic design of one such quadrupole is the focus of discussion in this article. The design process involves optimization of the pole tip, yoke and conductor size using two and three-dimensional finite element method tools.
Paper: WEPB084
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPB084
About: Received: 22 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 05 Nov 2025
WEPB113
Design of an online adjustable waveguide coupler for the TM020-mode cavity of proposed STCF
1944
The Super Tau-Charm Facility (STCF) project plans to use 12-15 TM020-mode cavities for each collider ring to compensate for the beam energy loss. Each cavity is designed to provide a voltage of 0.5 MV and a power of 250 kW for the beam. Therefore, an online adjustable waveguide coupler with a power capacity of CW 300 kW has to be developed for each cavity. This input coupler has a waveguide size the same as the half-height WR1500. The coupling between the cavity and the half-height WR1500 is realized by a rectangle hole with blending. This paper presents the electromagnetic design, the multipacting simulation, and the thermal and stress analysis of the input coupler in detail.
Paper: WEPB113
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPB113
About: Received: 27 May 2025 — Revised: 30 May 2025 — Accepted: 13 Oct 2025 — Issue date: 05 Nov 2025
WEPM029
Trajectory design for passing through solenoid magnet fringe field and method for adjusting its strongly X-Y coupled phase space for three-dimensional spiral beam injection
2020
A three-dimensional spiral beam injection scheme* has been developed to realize very precise measurement of the muon spin precession frequency in the level of sub-ppm. A 300MeV/c muon beam is injected into a precisely adjusted storage magnet of sub-ppm uniformity by applying medical MRI magnet technologies for J-PARC muon g-2/EDM experiment. A strongly X-Y coupled beam is required to deliver beam into the storage volume via strong radial fringe field volume of solenoid magnet followed by beam injection channel through iron yoke**. A dedicated design work of reference trajectory and beam phase space has been made in this injection section. In this presentation, we show evaluated the tolerance for the accuracy of the reference trajectory and the orbital position dependence of the required X-Y coupling parameters and discuss the required accuracy of the transport line placed upstream of the beam-line which includes eight rotating quadrupoles on the 10m of beam transport line**. Additionally, a pair of dedicated magnets called active shield steering magnet will be set at the entrance and the exit of the beam channel to perform orbital correction of the reference trajectory.
Paper: WEPM029
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPM029
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 05 Nov 2025
WEPM046
Optimising multi-turn extraction at CERN using transverse feedback
2077
Initial experimental investigations of transverse beam splitting, carried out at the CERN Proton Synchrotron, have demonstrated that transverse feedback is highly effective in controlling the characteristics of the transversally split beam. The feedback notably improves the intensity distribution among the beamlets and the emittance of the core, which is the portion of the beam remaining near its centre after the resonance-crossing process. The transverse feedback is set in resonance with the horizontal betatron tune while the tune crosses the fourth-order resonance, creating a double-resonance condition. A simple Hamiltonian model has been employed to explore the underlying double-resonance mechanism. This paper thoroughly examines detailed numerical simulations based on a realistic lattice model alongside beam measurements, to identify optimisation strategies for the use of transverse feedback in controlling the properties of split beams.
Paper: WEPM046
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPM046
About: Received: 02 Jun 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 05 Nov 2025
WEPM055
Design of beam phase space distribution to realize precise three-dimensional beam injection at J-PARC muon g-2/EDM experiment
2101
In the J-PARC muon g-2/EDM experiment, a three-dimensional beam injection scheme will be adopted to inject a 300 MeV/c muon beam into a compact storage orbit. In this scheme, a low-emittance muon beam with X-Y coupling is injected from the edge of a solenoidal magnet and guided to a compact beam storage region where the magnetic field is precisely tunned for a muon g-2 measurement with a good systematic uncertainty. The method to design the injected beam phase space distribution was previously unclear, as muons pass through an area with a largely position-dependent, non-linear, and time-dependent magnetic field created by the solenoidal fringe field and kicker field during the injection process. This presentation introduces a new design method. By utilizing a linear approximation of beam transportation, an acceptance is defined for the injected beam distribution. This acceptance is represented as a three-dimensional hyperplane, allowing for a search of an optimal beam distribution by comparing it to beam phase space distribution candidates. The presentation reports the procedure and results of this method, as well as its limitations due to the assumed linear approximation.
Paper: WEPM055
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPM055
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 05 Nov 2025
WEPM093
A particle-in-cell implementation of intra-beam scattering for Xsuite
2191
Intra-Beam Scattering (IBS) remains one of the primary mechanisms of emittance blow-up and performance degradation in the Large Hadron Collider (LHC) accelerator chain. The phenomenon is particularly relevant following the recent injector upgrades to achieve the high-brightness beams required for the High Luminosity LHC (HL-LHC) era. Traditional IBS models, as those already implemented in Xsuite, rely on the assumption of Gaussian beam distributions. However, observations in the CERN complex indicate the presence of q-Gaussian beam profiles, for which these models do not accurately reproduce IBS effects. To address this limitation, a Particle-In-Cell (PIC) approach was developed that operates independently of distribution assumptions. This methodology behind the PIC approach, and benchmarks against existing models as well as experimental data from the LHC are presented in this contribution. Current limitations are also discussed.
Paper: WEPM093
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPM093
About: Received: 22 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 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
WEPM095
Transverse coherent direct space charge: comparison between several approaches
2199
The proton driver of a future Muon Collider complex is designed to deliver a multi-GeV, short and high-intensity proton bunch to a target in order to maximize the muon yield. In the International Muon Collider Collaboration (IMCC), two high power H- Linac configurations are studied: a 2 MW with a beam energy of 5 GeV, and a 4 MW with a beam energy of 10 GeV. The Linac is followed by an accumulator ring and a compressor ring. With a single bunch intensity of 5.0e14 protons within a transverse emittance of ~15 mm mrad, strong space-charge effects can be expected in these rings. In this framework, different simulation codes used to estimate the transverse coherent space-charge mode frequency shifts in synchrotrons have been compared: BimBim, based on the Circulant Matrix Model (CMM); the Effective impedance method for space-charge; GALACTIC based on the Vlasov equation; the boxcar model for space-charge only; and the ABS model which assumes an Air-Bag bunch distribution in a Square well.
Paper: WEPM095
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPM095
About: Received: 29 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 05 Nov 2025
WEPS010
Photoinjector beam halo formation due to a secondary picosecond time-delayed laser pulse
2260
Beam halo formation is a significant challenge for high-intensity accelerators, as it can lead to performance degradation and radiation safety risks. This study investigates the formation and mitigation of beam halos caused by a picosecond time-delayed laser pulse, which generates a secondary electron bunch in the same RF bucket as the main bunch. The energy difference between the two bunches creates a defocusing effect, leading to the halo generation. Experimental validation of RF-Track simulations was conducted at the AWAKE Run 2c test injector (ARTI). The research outlines methods for identifying, analyzing, and mitigating laser-driven beam halo formation, contributing to more effective control of beam halos in accelerator operations.
Paper: WEPS010
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPS010
About: Received: 16 May 2025 — Revised: 31 May 2025 — Accepted: 02 Jun 2025 — Issue date: 05 Nov 2025
WEPS011
Machine learning-based symplectic model for space-charge effect simulation
2264
Symplectic simulation of space-charge effects is important for high-intensity particle accelerators. In this work, we propose to use a generative model to efficiently simulate space-charge effects in JuTrack, a Julia-based particle tracking code. The one-step symplectic transverse transfer map of the particles is obtained by differentiating the predicted space-charge Hamiltonian. This model effectively preserves the phase-space structure and reduces non-physical effects in long-term simulations by ensuring symplecticity in the calculation.
Paper: WEPS011
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPS011
About: Received: 16 May 2025 — Revised: 01 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 05 Nov 2025
WEPS029
Predicting losses in the SPS using longitudinal tomography during bunch shortening in the PS
2306
The efficient transfer of protons from the Proton Synchrotron (PS) to the Super Proton Synchrotron (SPS) is crucial for beams in the Large Hadron Collider (LHC). A particular challenge at the intensities required for the High-Luminosity LHC is the handover from a 40 MHz to a 200 MHz RF system. This requires a non-adiabatic bunch shortening in the PS triggered by a fast RF voltage jump. However, nonlinearity of the synchrotron frequency distribution causes tails to emerge during rotation, resulting in uncaptured beam in the SPS. The uncaptured particles lost at the start of acceleration in the SPS, and the additional flat bottom losses, can currently only be evaluated with the beam intensity and loss monitors. In this work, detailed studies of the bunch rotation in the PS were carried out both in simulations and in measurements. A tomography-based tool was developed to predict uncaptured losses in the SPS from bunch profile measurements in the PS during bunch shortening. This tool enables detailed monitoring of the PS-to-SPS transfer of LHC-type beams by identifying potential losses due to uncaptured beam, before injection into the SPS.
Paper: WEPS029
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPS029
About: Received: 27 May 2025 — Revised: 01 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 05 Nov 2025
WEPS035
Characterizing proton beam properties for cell irradiation study using GEANT4 simulation
2314
The purpose of this research is to characterize proton beam properties - beam energy, energy spread, beam size, and transverse emittance - to establish the initial setup for simulation in planning cancer cell culture experiments at the Cyclotron Medical Accelerator at King Chulalongkorn Memorial Hospital in Bangkok, Thailand. The characterization was performed using GEANT4 Monte Carlo (MC) simulations. Proton energies of 70 MeV, 100 MeV, 150 MeV, and 220 MeV were selected, and the 80%-20% distal fall-off of the depth profile was utilized to determine the energy spread. The simulated results were then verified against experimental data and compared with the Treatment Planning System (TPS). The details of the validating procedure, as well as results on the optimized energy spread, beam size, and emittance, and the irradiated setup for cell irradiation, will be discussed in this contribution.
Paper: WEPS035
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPS035
About: Received: 26 May 2025 — Revised: 30 May 2025 — Accepted: 30 May 2025 — Issue date: 05 Nov 2025
WEPS041
GPU accelerated longitudinal phase space tomography
2329
Longitudinal tomography is widely used in the CERN synchrotrons as an essential beam diagnostics tool. In recent years, more complex applications of phase space tomography, such as voltage calibration and multi-bunch tomography, have been explored. For these applications, large numbers of reconstructions are required, and computation time has a significant impact on usability. The current implementation is Python based, with the numerically intensive components written in C++. To further increase performance, a GPU-accelerated version has been developed using CuPy and CUDA. The most computationally demanding parts of the algorithm can now be run on the GPU, whilst maintaining the Python interface for maximum flexibility. Performance benchmarks showed speedups up to a factor of 35 in the scope of the entire application and even higher values when only considering the computationally intensive parts. This contribution discusses the implementation of GPU tomography as well as the additional performance improvements it enables.
Paper: WEPS041
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPS041
About: Received: 15 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 05 Nov 2025
WEPS062
RF design of an integrated X-band mode-launcher for an open-structure TW LINAC
2370
In this paper, we present the RF design of a mode-launcher integrated with an open-type, multi-cell 12 GHz 4-sector structure. The electromagnetic design is carried out using the 3D full-wave electromagnetic solver CST-Microwave Studio. To ensure compactness, a key focus of the integration process is the minimization of the distance between the coupler cell and the accelerating open structure. We evaluate the feasibility of two solutions: two conventional couplers, and another configuration with two mode-launchers employed at both the input and output ends of the accelerating structure. A comparison is performed to assess the performance of the proposed design
Paper: WEPS062
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPS062
About: Received: 29 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 05 Nov 2025
WEPS067
Development of high-power RF components for an X-band transverse deflector system at SACLA
2385
We have been developing an X-band transverse deflector system (XB-TDS) with sub-fs time resolution, which will be installed after the undulator sections at SACLA. A sub-fs XFEL pulse is desirable for user experiments such as the measurements of structural disordering in an XFEL interaction with a matter, as the degree of damage depends on the pulse duration. The demand for a shorter and shorter XFEL pulse is increasing. The SACLA’s XFEL pulse duration is 6 fs at FWHM. In order to achieve a shorter XFEL pulse duration and to satisfy users’ needs, a diagnostic system of the longitudinal bunch distribution is essential. We adopt an X-band frequency to efficiently deflect an 8 GeV electron beam. We feed 20 MW to the pulse compressor, and the peak power is increased to around 100 MW, which is divided into four cavities, generating HEM11 horizontal mode. We utilize a dipole magnet before the beam dump to measure the energy-time distribution.The current status is to manufacture high-power RF components such as deflector cavity, pulse compressor, and dummy load. In this presentation, we will show the design, manufacturing method, and commissioning status of these components.
Paper: WEPS067
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPS067
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 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
WEPS102
Reconstructing wake functions using Haissinski distributions from multiple bunch charges
2419
Accurate knowledge of wake functions is crucial in accelerator physics, serving as the cornerstone for understanding intra-bunch interactions and for controlling or mitigating instabilities that limit accelerator performance. Haissinski distributions, which describe the steady-state longitudinal bunch density, are intrinsically determined by the wake function experienced by the bunch. While these distributions are typically computed from a given wake function, we investigate the inverse problem: extracting the wake function directly from measured Haissinski distributions. In this theoretical work, we introduce a novel method to reconstruct wake functions by utilizing Haissinski distributions obtained at multiple bunch charges. By combining these profiles into an overdetermined system, we address challenges posed by the inverse problem, which is sensitive to noise and discretization errors. Here, our preliminary results suggest that the use of regularization techniques may help achieve more stable reconstructions of the wake function.
Paper: WEPS102
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPS102
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 05 Nov 2025
WEPS110
An updated HL-LHC halo population model based on recent experimental measurements
2435
The transverse beam halo population in the Large Hadron Collider (LHC) has been found to carry a significant fraction of the total stored beam energy, potentially reaching several percent. With the anticipated increase in beam brightness for the High Luminosity LHC (HL-LHC), this poses an increasing risk to machine safety, particularly during abrupt orbit shifts or critical component failures. A comprehensive understanding and an accurate modelling of the transverse beam halo are crucial for simulations of beam losses around the ring as a consequence of such failure scenarios in the HL-LHC era. Various models, including Gaussian, double-Gaussian, and q-Gaussian distributions, have been used to describe the LHC beam halos for fitting the measured distributions. This paper provides an in-depth analysis of halo modelling based on collimator scraping measurements from the LHC operational Run 2 and Run 3, and evaluates the accuracy and representativeness of these different distribution models.
Paper: WEPS110
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPS110
About: Received: 27 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 05 Nov 2025
WEPS113
Update on multi-objective genetic optimizations of the photoinjector for CARIE
2439
We present updated simulation results on the maximum brightness achievable by a 1.6-cell cold copper C-band photoinjector, designed for testing and commissioning as part of the Cathodes and RF in Extremes project at Los Alamos National Laboratory. Previous simulations highlighted the high brightness attainable with a 250 pC bunch charge, attributed to the high accelerating gradients and the benefits of a radially symmetrized photoinjector design. However, these earlier simulations relied on idealized temporal beam profiles, overlooked the temporal evolution of the gradients, and did not account for the influence of cathode plug geometry on the gradients—factors that significantly affect the maximum achievable brightness. In this work, we report the results of Multi-Objective Genetic Optimizations that incorporate more realistic temporal beam profiles and gradients, accounting for both the cathode plug geometry and the effects of time-dependent gradient evolution.
Paper: WEPS113
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPS113
About: Received: 28 May 2025 — Revised: 14 Jun 2025 — Accepted: 14 Jun 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
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
THPB034
A radiation-resistant distributed temperature sensor for CERN’s accelerators
2583
Optical Fibre Sensors (OFS) possess unique features, such as high sensitivity, versatility, and the ability to operate in harsh radiation environments. Distributed OFS are notable for enabling real-time monitoring over large-scale facilities, making them ideal for applications in particle accelerators. Their distributed measurement capabilities provide comprehensive monitoring while offering a cost-effective alternative to conventional pointwise technologies. As part of the Innovation work package of CERN’s Personnel Safety System Consolidation program, an experimental study was conducted to characterize the performance of a radiation-hard Distributed Temperature Sensor (DTS) to complement CERN’s safety systems, addressing cryogenic leaks and fire risks. Several fire tests were performed to assess the sensor's accuracy and temporal response under emergency-like conditions. A phenomenological model was derived from these tests to predict the system's behaviour in real-world scenarios. The obtained results are key to the first deployment and operation of a dedicated DTS demonstrator in a part of the LHC in 2025.
Paper: THPB034
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPB034
About: Received: 26 May 2025 — Revised: 14 Oct 2025 — Accepted: 14 Oct 2025 — Issue date: 05 Nov 2025
THPM008
Virtual temperature measurements of ferrite in in-vacuum kicker magnets
2699
The Large Hadron Collider (LHC) Injector Upgrade project has achieved unprecedented beam brightness levels, to fulfill the High Luminosity LHC requirements. This higher intensity has introduced significant challenges for some of the Super Proton Synchrotron (SPS) kickers, specifically concerning beam-induced heating and vacuum rise due to electron cloud. The primary concern is the integrity of the ferrite within the kicker magnets, which is critical to the system's operation and availability. Currently, temperature monitoring relies on temperature probes (PT100) installed on the magnet's frame, but these do not provide direct measurements of ferrite temperature. To address this limitation, we present a method using deep learning techniques to develop a virtual temperature sensor, enabling real-time monitoring of ferrite temperatures across the kicker module. We apply this approach to some of the SPS injection kicker family, the so-called MKP-S, and discuss the general applicability of the method to other systems.
Paper: THPM008
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPM008
About: Received: 20 May 2025 — Revised: 02 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 05 Nov 2025
THPM023
The journey towards a specialized text embedding model for accelerator physics
2730
We present PhysBERT and AccPhysBERT, specialized sentence-embedding models trained on 1.2 million arXiv physics papers and fine-tuned for accelerator physics, respectively. Evaluation across retrieval, clustering, and similarity tasks shows gains of up to 12\% over general-purpose models for physics corpora and 18\% for accelerator-specific tasks. Applications include semantic reviewer–paper matching, Retrieval-Augmented Generation for control-room logbooks, and rapid sub-domain adaptation. We analyze key design choices—data curation, masking objectives, and contrastive fine-tuning—and outline strategies for continual adaptation, providing a blueprint for domain-specific embeddings in the physical sciences.
Paper: THPM023
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPM023
About: Received: 30 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025
THPM035
MENT algorithm for transverse phase space reconstruction at SIRIUS
2758
The injector system of SIRIUS, the brazilian 4th generation synchrotron light source, currently operates with non-ideal injection efficiencies, which may impose limits to future top-up operation modes. Within this context, diagnostic techniques to access beam quality in the injector are essential tools for optimizations. In this work, the MENT algorithm was implemented for the reconstruction of two-dimensional probability densities, aiming to determine the electron density in the transverse phase space at the end of the LINAC. The implemented method has been validated through simulations of several distributions, demonstrating its reliability, and applied to analyze preliminary experimental results.
Paper: THPM035
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPM035
About: Received: 28 May 2025 — Revised: 01 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 05 Nov 2025
THPM043
Performance assessment of profile monitors at CERN’s LHC using systematic analysis tools
2777
In this paper, we investigate statistical and systematic tools to establish performance benchmarks for future beam profile measurement tools, using extensive data from both prototype and legacy Beam Wire Scanners and the Beam Synchrotron Radiation Telescope at the LHC. We detail direct and comparative analyses, including variability in beam size measurements, positioning accuracy, and profile shape fidelity relative to theoretical models, with particular focus on non-Gaussian tails influenced by the beam halo effect. This work establishes a foundation for systematic performance assessment applicable to both current and next-generation profile measurement tools.
Paper: THPM043
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPM043
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 05 Nov 2025
THPM044
Selecting 1D projections for 2D tomography reconstruction
2781
Previous works on reconstructing the 4D phase space using tomography require optimal selection of projection views to achieve accurate reconstruction. In 2D reconstruction, the process is straightforward, as an object can be evenly sampled by dividing the angles evenly. However, extending this concept from 2D to 4D is not intuitive. This work demonstrates that quaternions can be used to more effectively describe views in 4D and introduces the Fibonacci Flower algorithm and repulsive force algorithm to evenly space views in 4D space in order to achieve higher reconstruction accuracy.
Paper: THPM044
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPM044
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025
THPM063
Extended phase space tomography for EOSD simulation considering crystal geometry effects
2818
This theoretical study presents an advanced method for longitudinal phase space tomography in electron storage rings, focusing on reconstructing phase space densities from electro-optical spectral decoding (EOSD) measurements that incorporate crystal geometry effects. The EOSD crystal geometry significantly impacts the measurement signal due to signal integration along its length and interference from wake fields and Cherenkov diffraction radiation (ChDR). These effects add challenges to reconstructing the original phase space density from experimental data. To address these challenges, we integrate two theoretical frameworks. First, we employ the Vlasov-Fokker-Planck equation to model the turn-by-turn evolution of the charge density distribution. Second, CST simulations of the bunch profile characterize the electric field inside the crystal, enabling a tailored simulation for the EOSD system at the Karlsruhe Research Accelerator (KARA). By combining these approaches, we propose a refined tomography method that more accurately reconstructs the longitudinal phase space from sensor data, effectively capturing the interplay between bunch dynamics and the EOSD system configuration.
Paper: THPM063
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPM063
About: Received: 23 May 2025 — Revised: 01 Jun 2025 — Accepted: 04 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
THPM090
Study of Cherenkov diffraction radiation from radiator with periodic structure in THz-region
2874
We have studied classical radiation from relativistic electrons at a facility, test accelerator as a coherent terahertz source (t-ACTS), the Research Center for Accelerator and Radioisotope Science (RARiS), Tohoku University. Cherenkov radiation is generated when a relativistic charged particle passes through a dielectric medium, while Cherenkov diffraction radiation (ChDR) is emitted when the relativistic charged particle passes near the dielectric medium. In general, the ChDR spectrum is broadband. However, when a periodic structure is used as a radiator, interference effects can monochromatize the ChDR. At t-ACTS, a proof-of-principle experiment in the THz region was conducted using a high-density polyethylene (HDPE) radiator with a periodic structure. We successfully measured ChDR from radiator with periodic structure and achieved narrowband ChDR (NbChDR) in the THz region. This paper will discuss the characteristics of NbChDR in the THz region, as observed at t-ACTS.
Paper: THPM090
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPM090
About: Received: 26 May 2025 — Revised: 14 Oct 2025 — Accepted: 14 Oct 2025 — Issue date: 05 Nov 2025
THPM095
Benchmarking of new approach for analyzing transverse beam emittance measurement
2882
A recent analysis of emittance measurements highlighted the limited reliability of tools for precise method evaluation and error calculations. In this paper, a new analysis method is presented with its associated errors calculations. It is evaluated using realistic beam simulations and compared to the linear regression method commonly referenced in the literature. This new analysis method is shown to be easier to implement and provides results with a good confidence interval.
Paper: THPM095
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPM095
About: Received: 22 May 2025 — Revised: 02 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 05 Nov 2025
THPM111
Characterization of an IRRAD beam profile monitor at the CERN T8 beamline and possible improvements via cross-analysis with multiwire proportional chamber
2921
A new Beam Profile Monitor (BPM) system has been recently developed at the IRRAD Proton Facility to monitor the high-intensity 24 GeV/c proton beam from the CERN Proton Synchrotron accelerator. Thanks to the use of a new sensor manufacturing technology based on the microfabrication of metal nano-layers and updated readout electronics based on a Charge-Sensitive Amplifier with integrated 20-bit ADC and ARM controller, this system features minimal particle interaction, improved radiation hardness and higher sensitivity than earlier solutions. The growing users’ demand for precise irradiation of modern electronics, requiring ever more detailed beam information, is driving the introduction of future IRRAD upgrades, by leveraging on the presence of additional detector, a Multiwire Proportional Chamber, a detailed comparison-based analysis was performed to better characterize the IRRAD BPM system. It allowed us to introduce improvements in beam monitoring via advanced software and data processing. These results are crucial for future improvements at IRRAD by formulating requirements for the profile monitoring of new types of beams in IRRAD, e.g. heavy-ion and low-intensity proton beams.
Paper: THPM111
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPM111
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 05 Nov 2025
THPM112
Detecting anomalies in non-static environments: continual learning applied to CERN's kicker magnet
2924
The CERN accelerator complex relies critically on fast injection and extraction processes to transfer particle beams between accelerators via fast pulsed magnets, or kickers. Ensuring high availability is paramount, as the reliability of these systems directly impacts the large number of experiments conducted at CERN. In this paper, we propose to explore Continual Learning (CL) methods, specifically using Variational Autoencoders (VAEs), to develop an anomaly detection system for the fast kicker magnets. By continuously learning from evolving data while retaining prior knowledge, these models will be capable of detecting anomalies without the need for repeated retraining. This approach is particularly relevant for ensuring the reliability and stability of kicker magnets, where early anomaly detection is critical for preventing performance degradation.
Paper: THPM112
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPM112
About: Received: 27 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025
THPS021
Application of distributed temperature sensor for fire and cryogenic leak detection in accelerator tunnels
2996
High-energy accelerators like CERN’s Large Hadron Collider (LHC) present hazards characterized by temperature variations such as cryogenic leak or fire. Considering that LHC tunnels are large, underground, and radioactive areas, alternatives to traditional systems are explored to improve hazard detection. CERN is investigating the feasibility of installing a large-scale temperature monitoring system in LHC tunnels using Distributed Temperature Sensor (DTS) technology. Based on optical fibre, such a system would be resistant to the LHC radioactive environment and could detect temperature anomalies associated with both fire and cryogenic leak events. This paper presents ongoing studies and a prototype of DTS equipment in the LHC tunnel installed and tested at the beginning of 2025. This publication evaluates the DTS as a safety enhancement tool for accelerator facilities. The potential improvements brought by installing a DTS in LHC tunnels will also be discussed.
Paper: THPS021
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPS021
About: Received: 19 May 2025 — Revised: 31 May 2025 — Accepted: 01 Jun 2025 — Issue date: 05 Nov 2025
THPS022
Consolidation of personnel safety systems at CERN
3000
Personnel Safety Systems provide prevention and mitigation barriers to protect personnel, users, equipment, and the environment against the risks associated with the operation of the CERN Accelerators and Experiments, such as Radiation, Fire, Gas and Oxygen Deficiency Hazards. Due to the obsolescence or ageing of technology, evolutions of the facility and the Safety rules, it is now time to consolidate existing safety systems to prepare the CERN complex for the coming decades. A dedicated program has therefore been launched to refurbish the Fire, Gas and Oxygen Deficiency Hazard Detection Systems, and to implement a new Voice Alarm and Evacuation System in the Large Hadron Collider, among others. The paper provides insight into the methodology used to define the appropriate safety levels required to pragmatically ensure the Safety of personnel and the environment in the facility. Lessons learned from 20 years of operation, interpretation of the legal framework, and the process of risk definition and reduction through preventive and protection measures will be discussed. The main ongoing projects and the challenges ahead of the teams in charge will also be briefly presented.
Paper: THPS022
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPS022
About: Received: 23 May 2025 — Revised: 31 May 2025 — Accepted: 14 Oct 2025 — Issue date: 05 Nov 2025
THPS023
Renovation of the technical gallery network at CERN
3003
The distribution of services throughout a large scientific facility like CERN relies on a 14-km-long network of technical galleries. They provide essential utilities to CERN's office buildings and technical facilities, such as hot water, drinking water, compressed air, gas and electrical supply. This network has been gradually expanded or partially discontinued based on the Laboratory's needs. After 60 years of service, it is now time to refurbish the galleries and their associated infrastructure, to address existing issues and establish a robust foundation for the organization's future endeavors. A dedicated project has therefore been launched to enhance the maintainability, reliability, overall safety, and environmental performance of the technical infrastructure. Adapting all the networks to current and future needs following modern standards while minimizing service disruptions is also a priority. This paper provides insight into the methodology developed to re-engineer the targeted areas, the results of design studies, and lessons learned from implemented improvements. These insights may serve as a valuable example for other consolidation projects within CERN and beyond.
Paper: THPS023
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPS023
About: Received: 23 May 2025 — Revised: 14 Oct 2025 — Accepted: 14 Oct 2025 — Issue date: 05 Nov 2025
THPS044
Performances of new frequency sources for TRIUMF ISAC accelerator chains
3061
The TRIUMF ISAC-1 and ISAC-2 accelerator chains uses multiple fixed frequencies in their RF cavities. These include 5.8933 MHz, 11.7866 MHz, 35.36 MHz, 106.08 MHz and 141.44 MHz. These need to be synchronized in phase with respect to each other’s. The new frequency sources use x2, x3 and x4 low phase noise multipliers to generate these frequencies from a single low phase noise 5.8933 MHz frequency synthesizer. Bench tests have shown that the frequency multipliers do not generate additional phase noises, except those that are theoretically produced due to frequency multiplication. With an average performance frequency source as a reference which has -85dBc/Hz at 10 Hz offset, the integrated rms phase noise of 141.44 MHz multiplied output is less than 0.5°.
Paper: THPS044
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPS044
About: Received: 24 May 2025 — Revised: 30 May 2025 — Accepted: 01 Jun 2025 — Issue date: 05 Nov 2025
THPS053
Integrating community codes for accelerator design and optimization
3083
Advances in fidelity and performance of accelerator modeling tools, in tandem with novel machine learning capabilities, has prompted community initiatives aiming to realize “virtual test stands” that can serve as true analogues to physical machines. Such efforts require integrated, end-to-end modeling capabilities with support for parametric optimization and benchmarking. We present the ongoing development of an integrated Sirepo application to support the holistic modeling of accelerators. Our approach leverages existing modeling workflows, such as the Light Source Unified Modeling Environment (LUME), as well as community I/O frameworks, such as openPMD, to provide a toolbox for constructing and modeling beamlines. Users can build and test simulations using different community modeling tools, as well as connect individual tools to produce end-to-end simulations. Additional workflows have been developed to support machine learning tools that facilitate optimization and the development of surrogate models. We discuss some specific beamline modeling demonstrations as well as ongoing efforts to support code-agnostic design and development.
Paper: THPS053
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPS053
About: Received: 29 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 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
THPS120
Considerations for the transverse feedback system for the CERN FCC-ee collider ring
3206
The FCC-ee, a 90.7 km circumference e+ and e- collider under study at CERN, will require a transverse feedback system capable of handling risetimes as fast as four turns for the lowest order coupled-bunch modes. This can be realized by a distributed system of pick-ups and kickers in more than one location of the ring. The advantages are weighed with respect to the flexibility to respond to different choices of transverse tune working points and the possibility to operate the transverse kickers as an exciter for several measurement applications including as a depolarizer for energy calibration at Z and W energies. Options for the signal processing are outlined together with the overall specifications for the system components. The choice of frequency, a multiple of 40 MHz, is determined by requirements of the baseline 25 ns bunch spacing and the desire for a power efficient kicker system favoring stripline kickers. Performance of different variants of the system are compared in simulation and evaluated for added flexibility and complexity with respect to the placement in the ring.
Paper: THPS120
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPS120
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025