radiation
MOZN1
Overview of permanent magnet implementations for advanced light sources
42
The utilization of permanent magnets in the design of accelerator magnets has witnessed a surge in prominence, particularly within the realm of advanced light sources. Following pioneering initiatives at SIRIUS and ESRF-EBS, current projects are increasingly embracing permanent magnet technology. Notably, in the case of SLS2.0, over 30% of the magnets in the new storage ring are powered with permanent magnets. Permanent magnets offer manifold advantages, including compactness, much simpler requirements in terms of services (such as power supplies, cables, and cooling systems), and reduced operational costs. Nonetheless, they also present significant challenges that demand careful consideration. In this study, the author provides an overview of permanent magnet implementations across various projects and delves into a detailed analysis of the Swiss Light Source upgrade.
Paper: MOZN1
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOZN1
About: Received: 02 Jun 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 05 Nov 2025
MOPB007
Echo-enabled harmonic generation at the DELTA storage ring
87
Echo-enabled harmonic generation (EEHG) has been proposed as a seeding method for free-electron lasers but can also be employed to generate ultrashort radiation pulses at electron storage rings. With a twofold laser-electron interaction in two undulators ("modulators"), each followed by a magnetic chicane, an electron phase space structure with high harmonic content is produced, which gives rise to coherent emission of radiation at short wavelengths. The duration of the coherently emitted pulses in a third undulator ("radiator") is given by the laser pulse durations. Thus, EEHG pulses can be three orders of magnitude shorter but still more intense than conventional synchrotron light pulses. The worldwide first storage ring implementation of EEHG was undertaken at the 1.5-GeV synchrotron light source DELTA at TU Dortmund University by reconfiguring an electromagnetic undulator. With a total length of only 4.75 m, the setup is very compact and fits in a single straight section. The paper presents technical aspects of the EEHG implementation as well as first results.
Paper: MOPB007
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPB007
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025
MOPB014
Relativistic strophotron free electron laser
95
The scheme with quadrupole lenses is presented for realization relativistic strophotron type Free electron laser. Equations of motion are solved and trajectories are found. It is shown, that movement of electrons in presented scheme is stable in both transverse directions.
Paper: MOPB014
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPB014
About: Received: 24 Apr 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025
MOPB015
Tapering enhanced superradiance - tapering rate optimization using analytical magnetic field maps
98
THz sources are typically very limited in power, making high-power sources scarce. One of the most promising THz sources are the Free Electron Lasers (FELs), which can generate high-power THz radiation using an undulator structure. Undulator radiation is an incoherent synchrotron spontaneous emission whose energy is proportional to the number of particles in the beam (𝑁). By longitudinally bunching the charged particle beam, a coherent spontaneous emission is generated and referred to as a super-radiant emission. Unlike spontaneous emission, super-radiant energy yield is proportional to N^2. However, like typical FELs, the energy conversion efficiency is rather low. Here, we demonstrate a novel THz source structure based on a radiative interaction scheme of super-radiance – Tapered Enhanced Super-radiance (TES), which employs a tapered (amplitude) undulator in the zero-slippage condition. This method yields a significantly more powerful and efficient THz radiation source. An optimization algorithm was developed to obtain a tapering rate that yields the most efficient energy conversion from the electron beam to the radiation field.
Paper: MOPB015
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPB015
About: Received: 02 Jun 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025
MOPB021
Commissioning of the soft X-ray variable polarization afterburner at the European XFEL
106
Following the successful commissioning of the soft X-ray planar undulator system (SASE3), the European XFEL user community expressed a strong demand to extend the radiation properties and provide the possibility to obtain variable polarization modes. It was therefore decided to build a helical afterburner behind the SASE3 system in collaboration with Paul Scherrer Institute (PSI). The final installation of the undulators in the tunnel took place at the beginning of 2024. Since then, a series of measures have been taken to commission four APPLE-X undulators, which form the base for the helical afterburner. The main objective is to maximally suppress the linear polarization of planar undulators in order to obtain the purest radiation from helical undulators. The methods and results of the optimization to achieve a maximum contrast between the pulse intensity generated by planar and helical undulators as well as the operating experience are presented.
Paper: MOPB021
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPB021
About: Received: 26 May 2025 — Revised: 01 Jun 2025 — Accepted: 01 Jun 2025 — Issue date: 05 Nov 2025
MOPB034
Numerical simulation of on-axis helical undulator radiation using SCILAB-Xcos model
134
Abstract—A SCILAB Xcos model, developed using SCILAB software version 6.1.1, was implemented to simulate the on-axis radiation intensity of a helical undulator, (undulator parameter= 1, undulator wavelength 5cm, number of periods= 10, device length 0.6 m) with an electron beam (1, 2, & 3 GeV) and beam current as Ib = 3–6 × 10⁻⁶ Ampere. A numerical approach is utilized to perform the undulator radiation intensity calculations. The computed results were validated by comparing the on-axis undulator radiation intensity with those obtained from SPECTRA, an open-source synchrotron radiation (SR) calculation software.
Paper: MOPB034
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPB034
About: Received: 13 May 2025 — Revised: 05 Jun 2025 — Accepted: 08 Oct 2025 — Issue date: 05 Nov 2025
MOPB037
Orbit alignment study in the collimation section at the European XFEL
142
Orbit alignment plays an important role in free-electron laser (FEL) facilities, particularly in the collimation section, where multipoles are strategically positioned near the collimators as part of the specialized optics design. At the European XFEL, a strong dependence of lasing performance on the orbit in the collimation section has been observed. This study focuses on calibrating the central positions of the collimators using an orbit bump scanning technique combined with beam loss detection. Additionally, the influence of orbit alignment in the collimation section on lasing performance was systematically investigated, offering valuable insights into optimizing FEL operation.
Paper: MOPB037
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPB037
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 05 Nov 2025
MOPB055
Exploring lattice candidates for TPS upgrade
176
The design of lattice candidates for the Taiwan Photon Source (TPS) upgrade is under investigation, focusing on Multi-Bend Achromat (MBA) and Hybrid Multi-Bend Achromat (HMBA) configurations. A 5BA lattice, which offers relaxed hardware requirements, can achieve a natural beam emittance in the hundred pm-rad range for a 3 GeV storage ring. The 6BA configuration shows promise in achieving phase cancellation without the need for harmonic sextupoles but presents challenges due to limited available space. The HMBA scheme is attractive for its simpler configuration and reduced reliance on nonlinear magnets. Preliminary results highlight the characteristics and trade-offs of each configuration, providing guidance for the future TPS upgrade.
Paper: MOPB055
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPB055
About: Received: 27 May 2025 — Revised: 30 May 2025 — Accepted: 30 May 2025 — Issue date: 05 Nov 2025
MOPB105
Simulation and optimization of a sub-THz Cherenkov FEL at AREAL
246
A circular waveguide lined with a thin dielectric layer enables electron bunches propagating within the structure to radiate light in the (sub-)THz regime. In this work, we perform simulations of low-energy electron beams traversing extended waveguides to analyze the dynamics of beam bunching and lasing within the structure. By exploring the free-electron laser (FEL) process in this context, we demonstrate the potential of waveguides as a cost-effective alternative to undulator-based FELs. The study employs a simulated model of the AREAL LINAC at the CANDLE SRI to demonstrate these effects and provide realistic results. The simulations are performed using the space charge tracking algorithm ASTRA and the wakefield solver ECHO. For optimization of the system, the genetic optimization algorithm GIOTTO is applied to refine both the waveguide and accelerator variables. Using a 4 MeV electron beam with a charge of 300 pC, the optimized setup achieves a radiation frequency of 100 GHz with energy outputs exceeding 20 µJ in a waveguide of only 1.2 meters length. These results underscore the feasibility of this method, offering a innovative pathway to produce intense THz radiation.
Paper: MOPB105
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPB105
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 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
MOPM005
Refining dynamic aperture calculations for highly damped accelerators: methods and applications to the FCC-ee
270
The dynamic aperture is a key metric for assessing the stable phase space of particle accelerators and evaluating their overall stability. However, in highly damped accelerators such as high-energy electron synchrotrons like the Future Circular Collider (FCC-ee), the rapid amplitude variation of tracked particles over a few turns introduces significant sensitivity to initial conditions and the particle's starting location. This work investigates these dependencies in the context of the FCC-ee and highlights their implications for stability analyses. We propose novel, more reliable methods to compute the dynamic aperture that account for these effects, improving the accuracy of stability predictions. First results from the application of these methods to the FCC-ee are presented, demonstrating their potential for advancing the understanding of beam dynamics in next-generation accelerators.
Paper: MOPM005
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPM005
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 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
MOPM041
Estimation of FCC-ee beam lifetime from full lattice tracking
410
Across its energy range, the beam lifetime at the Future Circular Collider $e^+e^-$ (FCC-ee) will be dominated by radiative processes occurring as a result of the beam-beam collision, namely by beamstrahlung and small angle radiative Bhabha scattering. Although approximate analytical expressions exist for estimating the lifetime, it is most accurately evaluated by performing multiparticle tracking simulations, due to the interplay of magnetic errors with non-linear forces due to the beam-beam interaction. This contribution presents the first comprehensive study of the FCC-ee beam lifetime including both effects, simulated with the Xsuite framework.
Paper: MOPM041
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPM041
About: Received: 24 May 2025 — Revised: 02 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025
MOPM067
Radiation load from radiative Bhabha scattering in the FCC-ee experimental insertions
478
The lepton Future Circular Collider (FCC-ee) at CERN provides electron-positron collisions at four interaction points (IPs) along a 91 km ring, with beam energies spanning from 45.6 GeV (Z pole) to 182.5 GeV (ttbar threshold). The radiation showers produced by these collisions can reach sensitive components of the surrounding machine elements, possibly affecting their performance and lifetime. This contribution examines the case of radiative Bhabha scattering, which generates off-momentum beam particles that can be lost downstream. Some losses occur already at the superconducting final focusing quadrupoles (FFQs), where they can cause quenches and degradation of the coil materials. In this work, the Monte Carlo code FLUKA is used to study the impact of radiative Bhabha in the experimental insertion regions of FCC-ee. The radiation load in the FFQs and the radiation levels in the nearby tunnel and machine elements are simulated for the Z-pole and ttbar operational modes. For the FFQs, a tungsten shielding layer with optimized thickness is proposed to mitigate the radiation load in the magnet coils.
Paper: MOPM067
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPM067
About: Received: 28 May 2025 — Revised: 30 May 2025 — Accepted: 30 May 2025 — Issue date: 05 Nov 2025
MOPM068
FCC-ee radiation environment and shielding
482
The secondary radiation fields generated by synchrotron photons pose a significant challenge for equipment in high energy electron and positron storage rings like the Future Circular Collider (FCC-ee) at CERN. The annual ionizing dose can reach MGy-levels in the FCC-ee tunnel and requires the design of a dedicated radiation shielding enclosing the photon stoppers in dipoles. In this paper, we present a first optimization of the shielding design, taking into account different aspects such as shielding efficiency, engineering and integration constraints, raw material costs, and radiological considerations. We demonstrate that the proposed shielding solution can decrease the dose in the tunnel by about two orders of magnitude, which considerably reduces the need of expensive radiation-hard equipment. In addition, we explore the option of housing accelerator electronics in a dedicated bunker near lattice quadrupoles, which can possibly allow for custom-off-the-shelf-based radiation tolerant electronics systems. We quantify the expected radiation levels in this bunker, which are driven by photo-neutron production by the high-energy component of the synchrotron spectrum.
Paper: MOPM068
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPM068
About: Received: 27 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025
MOPM069
Power deposition studies for the FCC-ee halo collimation system
486
The Future Circular Collider (FCC-ee) at CERN requires a betatron and momentum collimation system for reducing particle backgrounds in the detectors, and for protecting the machine in case of excessive beam losses. The system is composed of primary and secondary collimators, which will be housed in one of the technical insertions of the 91 km ring. In this paper, we present a first assessment of the beam-induced power deposition in the collimators using FLUKA Monte Carlo simulations. We show that dedicated shower absorbers are needed in the collimation insertion, which intercept secondary particles from the halo collimators and reduce the energy leakage to the environment. A first optimization of the shower absorber configuration is presented, considering different absorber positions and absorber lengths. We demonstrate that the power absorption of the betatron collimation system can be increased from about 50% to over 80% by adding two shower absorbers between primary and secondary collimators.
Paper: MOPM069
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPM069
About: Received: 27 May 2025 — Revised: 22 Oct 2025 — Accepted: 22 Oct 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
MOPM077
Commissioning of the new FLASHlab@PITZ beamline extension
498
Over the past year a new beamline dedicated to R&D for electron FLASH cancer radiation therapy and radiation biology was set up at the Photo Injector Test facility at DESY in Zeuthen (PITZ). The beamline runs in parallel to the SASE THz beamline at PITZ and is connected to it with an achromatic dogleg. The dispersion within the dogleg is utilized to install an aperture to scrape off-energy dark current. The following straight section of the beamline contains a kicker system which will be capable of distributing electron bunches from a single bunch train freely over an area of 25mm x 25mm within one millisecond. So far, only the slow kicker for the vertical plane is installed – the fast kicker for the horizontal plane will be installed soon. Behind an exit window is an experimental area for conducting irradiation experiments with the 22 MeV electron beam, which can accommodate setups for a wide range of experiments. Here we report the completion of the construction of the new beamline with detailed information about the setup. Preparation results of the PITZ robot and further data of the new experimental area are described. Additionally some new simulation results are given.
Paper: MOPM077
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPM077
About: Received: 26 May 2025 — Revised: 08 Oct 2025 — Accepted: 08 Oct 2025 — Issue date: 05 Nov 2025
MOPS014
Development of a 500 MHz high power solid state power amplifier based on GaN transistors
611
The adoption of Solid State Power Amplifier (SSPA) is rapidly increasing in major accelerators worldwide, replacing tube amplifiers such as Klystron and IoT. This study aimed to develop a High-Power RF system for Multipurpose Synchrotron Radiation Accelerators and to design and implement a GaN transistor-based SSPA. Through this research, we verified control performance equivalent to that of a 150 kW SSPA and successfully developed a prototype of a 5 kW RF module. Experimental results confirmed that the GaN transistor-based SSPA provides high efficiency and stable performance in the 500 MHz band, and based on this, we established a performance assurance plan for the 150 kW SSPA. This study demonstrates that GaN devices can effectively replace LDMOS devices with similar performance and competitiveness in the RF applications operating in the 500 MHz frequency range, which has traditionally been dominated by LDMOS. These results have significant implications for enhancing the performance and efficiency of High-Power RF systems and are expected to greatly expand the potential applications of GaN-based SSPA in various scientific and industrial research fields.
Paper: MOPS014
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPS014
About: Received: 28 May 2025 — Revised: 21 Oct 2025 — Accepted: 21 Oct 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
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
MOPS060
Undulators for BESSY III
748
Helmholtz Zentrum Berlin is engaged in the conceptual design of the BESSY III facility. The BESSY III storage ring will be a fourth generation synchrotron light source with an emittance of about 100 pm rad and an energy of 2.5 GeV. It will be equipped with advanced undulators to provide users with tailor-made light. So far cryogenic permanent magnet undulators, hybrid planar undulators and a variety of APPLE II undulators - conventional (in-air) and in-vacuum are planned to meet user requirements in terms of spectral range, flux and polarisation. In this paper we give an overview of the planned undulators, discuss some of the design aspects and present their expected performance.
Paper: MOPS060
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-MOPS060
About: Received: 25 May 2025 — Revised: 01 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
TUXD1
Personnel and machine protection for high power accelerator commissioning, operations, and power ramp up
844
Safety is one of the main concerns in accelerator society. The key FRIB strategies and experience can be shared, leading to the successful FRIB operations with no safety-related incidents and meeting stringent standard in a university area. Personnel protection and machine protection are key to high power frontier facilities like FRIB. For a facility built in the middle of university campus with heavy ion beam power being ramped up order of magnitude higher than the current record, stringent engineered and administrative controls and state-of-the-art technologies are needed to safeguard commissioning, operations, and upgrades.
Paper: TUXD1
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUXD1
About: Received: 28 May 2025 — Revised: 03 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
TUCN3
Commissioning of the South African Isotope Facility
928
The South African Isotope Facility (SAIF) is a radioisotope production facility based around a 70 MeV Cyclotron from IBA. SAIF was commissioned at the end of 2023 and commenced commercial isotope production in 2024. The facility is located in three vaults at iThemba LABS in Cape Town. The vault design, radiation modelling, and an overview of construction are presented. The designs and commissioning of the cyclotron, beam lines, wobbler magnet, dedicated target stations and target transport system are described and discussed, along with their current performance.
Paper: TUCN3
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUCN3
About: Received: 28 May 2025 — Revised: 31 May 2025 — Accepted: 31 May 2025 — Issue date: 05 Nov 2025
TUPB004
Measurement of the transversal Muon Rate at the proposed CODEXb experiment with the Timepix3 Radiation Monitor
940
Using a Timepix3 radiation monitor, we measured the muon rate at the proposed CODEXb experiment location within the Large Hadron Collider (LHC) during luminosity production at the LHCb collision point. Filters were applied to the data to differentiate the background radiation from the muon signal by analyzing the particle track morphology—specifically cluster type, length, and angle within the detector. The resulting filtered muon rate was determined to be 8.6$\pm$1.5 counts/(cm $ \cdot$ pb$^{-1}$). These results were further compared to simulations performed with the FLUKA Monte Carlo code, showing agreement within the uncertainties.
Paper: TUPB004
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPB004
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 05 Nov 2025
TUPB005
Measurement of the muon rate at the SND Experiment with the Timepix3 radiation monitor
944
Using a Timepix3 radiation monitor, the muon rate at the Scattering and Neutrino Detector (SND) location at the Large Hadron Collider (LHC) was measured during luminosity production at the ATLAS collision point. Filters are applied on the measured data to distinguish between background radiation and the muon signal by analyzing the cluster type, length, and angle. The results were compared to the those reported by SND, revealing a count rate ratio of 1.24 of Timepix3 to SND measurements. Taking advantage of the Timepix3 detector capabilities, further features of the muon flux are studied. First, the bunch-by-bunch spacing (25 ns) of the beam is assessed owing to the time resolution of the Timepix3 detector (1.5265 ns). The spatial distribution of the muon flux in the Timepix3 detector surface has been studied, however the detector size is too small for the measured muon rate to yield any distinct patterns, assuming the muon gradient as measured by the SND detector. Finally, the energy deposition $E_{dep}$ of the muons in the Timepix3 detector has been studied, consistent with FLUKA simulated muons coming from ATLAS collisions, with an energy distribution peaked at 100 GeV.
Paper: TUPB005
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPB005
About: Received: 28 May 2025 — Revised: 31 May 2025 — Accepted: 02 Jun 2025 — Issue date: 05 Nov 2025
TUPB006
Readiness of the HEARTS@CERN facility for space electronics high-energy heavy-ion testing
948
The HEARTS@CERN activity in the framework of the HEARTS (High-Energy Accelerators for Radiation Testing and Shielding) EU project is targeted at enhancing Europe’s high-energy (>100 MeV/n) heavy ion electronics irradiation capability through the development of an irradiation beam combining unique penetration and ionization characteristics. These types of tests are essential for exploiting commercial electronics in space. Throughout 2024, the HEARTS@CERN efforts have focused on achieving and demonstrating compliance with the space user radiation effects testing requirements. This includes being able to offer a wide range of energies (and Linear Energy Transfer values) and fluxes, with a high level of accuracy and a rapid change between parameters. Moreover, large homogeneous beams are necessary for enabling the test of multiple electronic components in parallel, and for performing board level testing. This work will present requirements for high-energy heavy ion testing along with the level of compliance achieved, as demonstrated during the November 2024 HEARTS@CERN user run, with a focus on the beam related parameters, but including also facility and procedural considerations.
Paper: TUPB006
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPB006
About: Received: 27 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025
TUPB007
Radiation levels from a Beam Gas Curtain instrument at the LHC at CERN during ion operation
952
A prototype Beam Gas Curtain (BGC) monitor was installed on beam 1 at the Large Hadron Collider (LHC) at CERN to provide 2D images of the transverse beam profile during the ongoing Run 3 (2022 - to date) and in view of the High Luminosity LHC upgrade (HL-LHC). By design, the BGC operation generates collisions between the beam particles and an injected gas jet proportionally to the beam intensity and the gas density, possibly causing radiation-induced issues to the downstream LHC equipment. This operation has been studied for the proton run, and now the scenario for lead (Pb) ion beam is scrutinized. The radiation showers from the BGC are characterized using measured data from different LHC radiation monitors during the Run 3 BGC operation, along with Monte Carlo simulations with the FLUKA code. Finally, predictions of the expected radiation showers during operation of the BGC in the HL-LHC era are discussed.
Paper: TUPB007
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPB007
About: Received: 28 May 2025 — Revised: 29 May 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
TUPB037
New linac designs by High Energy Sources R&D Group at Varex Imaging
1050
High Energy Sources R&D group at Varex Imaging has developed several Accelerator Beam Centerline (ABC) and Linear Accelerator (linac) designs in the past 8 years. Here we present a summary of our recent progress. M9V linac, featuring our new ABC, is being developed to further improve characteristics of 9 MeV accelerator. The new ABC is shorter than the standard 9 MeV linac, and the focusing solenoid is completely removed. The overall system design increases dose rate and reduces the weight and complexity. In addition, our new version of K15, called K15V or V15, is being redesigned with a hybrid Standing Wave (SW) and Traveling Wave (TW) reverse feed configuration, protected by US patent. We expect it to produce significantly higher dose rate of up to 40000 R/min at 1 m. The first SW section of this linac may be used separately in 9 MeV system we called V9, which is also expected to deliver higher dose rate of up to 20000 R/min while substantially reducing neutron yield compared to 15 MeV machine. We have also tested a new concept implemented on 6 MeV linac, which permitted reducing the electron beam focal spot size to 350±150 µm without utilization of any magnetic systems.
Paper: TUPB037
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPB037
About: Received: 28 May 2025 — Revised: 13 Oct 2025 — Accepted: 13 Oct 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
TUPB047
CERN-MEDICIS: A unique facility for the production of radionuclides for medical research
1071
The MEDICIS facility is a unique facility located at CERN, dedicated to the production of non-conventional radionuclides for research and development in imaging, diagnostics and radiation therapy, and based on offline mass separation. It exploits a classified area for handling of highly radioactive open sources, a dedicated isotope separator beam line, a target irradiation station at the 1.4 GeV Proton Synchroton Booster (PSB) and receives activated targets from external institutes during CERN Long Shut-Downs. After collection, the batch is prepared to be dispatched to a research center. Since its commissioning in December 2017, the facility has provided novel radionuclides such as Ba-128, Tb-155, Sm-153, Tm-165 Ra-224/Pb-212 and Ra-225/Ac-225 with high specific activity, some for the first time, to research institutes part of the collaboration. CERN-MEDICIS has advanced significantly to reach mature processes to translate into clinical application for the most promising radionuclides.
Paper: TUPB047
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPB047
About: Received: 17 May 2025 — Revised: 02 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 05 Nov 2025
TUPB056
Development of a friendly high-energy irradiation environment for future space developments
1091
Effect assessments of high-energy radiations on materials and equipment are expected to become increasingly important in near future space developments. We initiated a project to construct an irradiation environment with high-energy radiations using the electron linear accelerator at Nihon University. The advantages of using this accelerator include the accelerations up to 100 MeV for high-energy and high-dose irradiations, its easy accessible location from Tokyo area. These advantages help many users including venture companies to use the irradiations with much less difficulties, that we consider as an important key to enhance future space developments. The electron linear accelerator sends electron beams with a wide energy range to the FEL line by bending them 90 degrees with two 45-degree bending magnets. Irradiation tests are planned to be conducted using the radiation produced in this process. In this study, we present a simulation result on the acceleration process of the electron beam and the amount of radiation generated by the 45-degree bending magnets. We also show dosimeter measurements by the high-energy irradiations to be compared with the simulation results.
Paper: TUPB056
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPB056
About: Received: 29 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 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
TUPB091
Dose calculations for warm quadrupoles in the LHC off-momentum cleaning insertion
1143
Interaction Region 3 (IR3) of the Large Hadron Collider (LHC) houses the off-momentum collimation system, designed to remove particles with significant energy deviations. The interaction of the beam with this multi-stage collimation system generates particle showers that impact various elements, including quadrupole magnets in the straight section. Radiation exposure to magnet coils and spacers raises concerns about potential damage. The upcoming High-Luminosity (HL) LHC upgrade will significantly increase radiation doses, necessitating further assessments. While shielding inserts were added to the quadrupoles during a previous shutdown, further shielding may be required, prompting dose predictions through the HL-LHC era in the 2040s. This paper presents FLUKA simulations where the off-momentum proton and heavy ion losses in LHC Run 2 (2014-2018) and Run 3 (2022-2026) is estimated from Beam Loss Monitors. These estimates serve as normalization factor for calculating the dose deposited in the quadrupoles. These results are then extrapolated to HL-LHC operational parameters, offering unprecedented insight into the future IR3 radiation environment
Paper: TUPB091
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPB091
About: Received: 26 May 2025 — Revised: 22 Oct 2025 — Accepted: 22 Oct 2025 — Issue date: 05 Nov 2025
TUPM030
Analysis of laser-electron-radiation interaction in laser modulators for three SSMB scenarios
1227
Recent studies explored a novel storage ring light source using steady-state microbunching (SSMB). Existing investigations predominantly focused on single-particle and pure-optics phenomena. Many SSMB schemes employ laser modulators, comprising an undulator and copropagating laser beam, to manipulate electron longitudinal bunch length. Electron bunch traversing the undulator emits coherent undulator radiation near the resonant wavelength. Laser beams may form a closed path to become a laser enhancement cavity. We developed a model* analyzing laser-electron-radiation interactions in laser modulator cavities, considering mirror-induced losses, externally injected laser power compensation, and coherent undulator radiation dynamics on multiple turns. Our approach integrates beamline transfer matrices with a low-gain FEL oscillator model, enabling quick estimation of the dynamic effects. In this work we examine three SSMB scenarios, amplifier, frequency-beating, and harmonic, accounting for laser-electron-radiation interactions. Under preliminary design parameters, our analysis suggests feasibility for the three scenarios. A potential self-seeding SSMB scheme is also investigated.
Paper: TUPM030
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPM030
About: Received: 23 May 2025 — Revised: 29 May 2025 — Accepted: 01 Jun 2025 — Issue date: 05 Nov 2025
TUPM031
Courant-Snyder formalism for modeling, optimizing and simulating broadband THz radiation transport
1231
In order to exploit the scientific potential of user-oriented accelerator facilities, it is necessary to provide adequate pump sources to enable pump-probe science. The EuXFEL R&D project, STERN, aims to equip X-ray users with an accelerator-based THz source matching the high repetition rate of the XFEL. The proposed THz radiation generation methods involve Cherenkov wakefield structures and diffraction radiation, aiming to produce a spectrum from 300 GHz to 30 THz. To enable experimental characterization, both broadband and narrowband pulses must be transported through a single beamline to a radiation-shielded laboratory. A major challenge has been the simulation, optimization and design of the STERN beamline. The OCELOT accelerator lattice optimizer is adapted for optical transport with mirrors substituting traditional focusing magnets. The performance is corroborated using a THz transport code that considers beam clipping and diffraction. The optimized beamline achieves efficient transport over 10 meters, maintaining over 75% source-to-end efficiency across the frequency range. This development marks a significant step forward in THz beamline design for advanced applications.
Paper: TUPM031
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPM031
About: Received: 28 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025
TUPM032
Cherenkov waveguide design for THz production at the EuXFEL
1235
The EuXFEL R&D project, STERN, aims to provide X-ray users with an accelerator-based THz source synchronized with the X-ray repetition rate. The main proposed THz generation method consists of electron beam wakefield excitation in Cherenkov waveguides. This work focuses on the design of a copper block that holds an array of waveguides to cover the radiation spectrum spanning from 300 GHz to 30 THz. These will include a variety of lengths and dielectric layer thicknesses to vary the spectral contents of the excited TM modes. Additionally, driving the wakefield generation process with an off-axis electron beam causes the excitation of HE modes, which are of great interest to the user community and add to the spectral content of the THz pulse. To further increase pulse energy, the implementation of radiation incouplers is analyzed, demonstrating the potential for capturing the electron beams self-field completely. Such wakefield structures offer a novel option for delivering versatile THz sources tailored to next-generation pump-probe experiments.
Paper: TUPM032
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPM032
About: Received: 27 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025
TUPM035
Performance of terahertz-wave beamlines at Nihon University's laboratory LEBRA
1239
National Institute of Advanced Industrial Science and Technology (AIST) has collaborated with Nihon University to study generation of high-intensity terahertz waves using coherent radiations at the Laboratory for Electron Beam Research and Application (LEBRA) at Nihon University. In a straight section for parametric X-ray (PXR) generation, developments of various types of coherent radiation sources and a study of superimposed coherent radiation using a ring-type resonator have been conducted. Coherent edge radiation (CER) generated in the downstream bending magnet is transported to an experimental room using the PXR beamline and is used for spectroscopic measurements and imaging experiments in an acrylic box filled with dry air. In a straight section for an infrared free-electron laser (FEL), CER generated by a downstream bending magnet during FEL oscillations is extracted from an FEL resonator by a toroidal mirror with a hole.* The extracted CER is reflected by a sapphire substrate coated with Indium-tin oxide and transported to the room using an FEL beamline. In this presentation, the status of the two THz beamlines at Nihon University's laboratory LEBRA will be described.
Paper: TUPM035
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPM035
About: Received: 26 May 2025 — Revised: 13 Oct 2025 — Accepted: 13 Oct 2025 — Issue date: 05 Nov 2025
TUPM036
Feasibility study of a THz beamline design for the THz user facility at NSRRC
1243
Feasibility design of THz beamlines for the use of the superradiant THz free electron laser driven by the NSRRC high brightness photo-injector has been studied. The Accelerator Test Area (ATA) building, where the photo-injector installed, will be transformed into a THz user facility that meets radiation safety regulations. Narrow-band intense superradiant THz radiations with pulse energy as high as 20 μJ and tunable central frequency from 0.6 to 1.4 THz, generated by injecting an ultrashort electron beam into a U100 planar undulator, can be a useful tool for nonlinear and time-resolved pump-probe experiments. There will be two stages for user experiments. Phase I will be opened for users with the experimental station installed right after the THz sources in the accelerator tunnel. Another THz beamline, which is currently being designed to maintain the quality of THz radiations after propagation over longer distances, will be built for user experiments in Phase II. This report briefly describes the beamline design and the operation of user experiments in Phase I.
Paper: TUPM036
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPM036
About: Received: 27 May 2025 — Revised: 29 May 2025 — Accepted: 01 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
TUPM071
Finalizing the multiphysics design of a high heat-load superconducting undulator
1322
RadiaBeam is developing and manufacturing a 15mm period, high temperature superconductor undulator using Magnesium Diboride (MgB2) wire at 10K-15K temperature range. This temperature range can be achieved by cryocooler, a simpler and less expensive cryogenic solution compared to a liquid helium approach. After optimizing the thermal-mechanical design, the operating temperature is finalized at 7K. We examine the current density, critical field, tensile stress, tensile strain, and temperature of MgB2 wire in multiphysics approach and determine the operating field to be 1.13T with safety margin. A quench-protected power system is developed for training the SCU to the operating point in controlled ramp rate. The SCU will be characterized by in-vacuum pulse wire measurement system.
Paper: TUPM071
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPM071
About: Received: 28 May 2025 — Revised: 31 May 2025 — Accepted: 31 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
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
TUPM077
New developments in the design of the muon production target area of a multi-TeV muon collider
1333
As the International Muon Collider Collaboration advances the conceptual design for a multi-TeV muon collider facility, new technical constraints continue to arise in the muon production stage, where a high-power proton beam interacts with a target. Achieving the required muon bunch intensity may necessitate increasing the primary beam power up to 4 MW. Consequently, the shielding design must address sustained radiation exposure, particularly on critical components such as superconducting solenoids, which generate strong magnetic fields essential for capturing both pions and decay muons. Additionally, the portion of the proton beam that passes through the target without undergoing inelastic interaction leads to a very high power density in the chicane area and an intense ionising dose on the insulation material of the normal-conducting chicane magnets, which are used to separate the muon component. A robust method to safely extract these spent protons is crucial. This study presents the latest results from FLUKA Monte Carlo simulations, modelling the radiation load on solenoids and the extraction channel across varying beam power and target designs.
Paper: TUPM077
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPM077
About: Received: 27 May 2025 — Revised: 01 Jun 2025 — Accepted: 01 Jun 2025 — Issue date: 05 Nov 2025
TUPM095
Coherent high-harmonic generation with laser-plasma beams
1379
Active energy compression scheme enables generating laser-plasma accelerator electron beams with a small relative slice energy spread, of the order of 10 ppm. When modulated by a laser pulse, such beams can produce coherent radiation at very high, about 100-th harmonics of the modulation laser wavelength, which are hard to access by conventional techniques. The scheme has a potential of providing additional capabilities for future plasma-based facilities by generating stable, tunable, narrow-band radiation.
Paper: TUPM095
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPM095
About: Received: 06 May 2025 — Revised: 29 May 2025 — Accepted: 01 Jun 2025 — Issue date: 05 Nov 2025
TUPM099
Initial characterization of a laser-driven betatron radiation source in the EuAPS project
1391
Betatron radiation is the spontaneous emission of radiation produced by the betatron oscillations of electrons in a plasma during the Laser Wakefield Acceleration (LWFA) process. A high-intensity and ultra-short laser pulse is focused on a supersonic gas jet, simultaneously creating a plasma, injecting, and accelerating electrons, which then emit this radiation. In the framework of the EuPRAXIA project, EuAPS (EuPRAXIA Advanced Photon Source) will be the first user-oriented radiation source based on betatron radiation developed at LNF-INFN Frascati in collaboration with CNR and the University of Rome Tor Vergata. This radiation source has a wide range of applications, including materials science, medical and biological research. The user facility aims to deliver 1-10 keV photons using a compact laser-driven plasma accelerator operating in a self-injection mechanism, which occurs in highly nonlinear laser-plasma interaction. In this contribution, we present the expected parameters of the source and the result of several dedicated experimental campaigns conducted within the EuAPS project to provide the preliminary characterization of the x-rays betatron radiation source.
Paper: TUPM099
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPM099
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 05 Nov 2025
TUPM115
Simulation and developmental status for generation and detection of THz using coherent transition radiation technique in Delhi Light Source
1411
THz technology being a highly growing and potent field, finds use in a wide range of research applications. Delhi Light Source (DLS) at IUAC, New Delhi is at final stage of commissioning to produce intense and coherent THz radiation based on pre-bunched Free Electron Laser principle. As an addition to the narrowband undulator radiation, broadband Coherent Transition Radiation (CTR) will also be produced by passing femtosecond electron beam bunches through an Al foil . To generate the electron bunches with multi-micro bunch structure from the RF photo cathode gun, a state of the art femtosecond fiber laser system has been developed in collaboration with KEK, Japan. The generated electron beam bunches with energy up to 8 MeV is expected to produce CTR maximum up to few microjoule of energy. The multi-micro bunch structure increases the average CTR power. This paper reports the simulation results of the CTR showing the power, angular and frequency distribution produced from DLS facility. The schematic design and developmental status of DLS for generation and detection of THz CTR are also discussed.
Paper: TUPM115
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPM115
About: Received: 27 May 2025 — Revised: 30 May 2025 — Accepted: 31 May 2025 — Issue date: 05 Nov 2025
TUPS060
Electron cyclotron resonance accelerator for industrial radiation processing
1567
Industrial radiation processing is used on a wide variety of products, including medical devices for eradication of pathogens, food for preservation and safety, and plastics for material property modification. But millions of curies of Co-60 that are still used in some industrial sterilization facilities can pose a significant security risk in an act of radiological terrorism. Lower-cost electron beam systems with high beam-power efficiency and high reliability are needed to replace Co-60 based sterilization systems. A novel accelerator under development, electron Cyclotron Resonance Accelerator (eCRA) is described here. It is highly compact and efficient to produce high power electron beams and x-ray beams. The several attractive features of eCRA include: a compact robust room-temperature single-cell RF cavity as the accelerator structure; continuous ampere-level high current output without bunching; and a self-scanning accelerated energetic e-beam, obviating need for a separate beam scanner. Details of design and predicted performance will be described.
Paper: TUPS060
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPS060
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025
TUPS093
Permanent hybrid helical micro-undulators for FELs and inverse FELs
1595
High-field micro-undulators are one of the key elements in most compact Terahertz and X-ray FEL projects. In our works, helical undulators of several helices, each made of a single piece of rare-earth magnet, are proposed for this purpose. We demonstrated previously the possibility of high-precision manufacturing helices with centimeter periods using the Wire Electric Discharge Machining. In this paper, we will discuss an experimental prototype micro-undulator of two oppositely longitudinally magnetized NdFeB helices with a period of 6 mm and an inner hole diameter of 1 mm, creating a transverse field close to 1 T. The magnitude of the field and/or the inner diameter of the helices can be significantly increased by using hybrid systems with two longitudinally pre-magnetized rare-earth and two pre-unmagnetized steel helices. We are currently developing methods for manufacturing, assembling and measuring the parameters of such systems with periods of 6 and 3 mm and a field of 1 T and will demonstrate the corresponding results in the presentation.
Paper: TUPS093
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPS093
About: Received: 14 May 2025 — Revised: 13 Oct 2025 — Accepted: 13 Oct 2025 — Issue date: 05 Nov 2025
TUPS094
Diagnosing an In-Vacuum Undulator in the ALS storage ring
1598
The Advanced Light Source (ALS) has an in-vacuum undulator named “LEDA”. It was installed in 2019 and provides high-brightness, high-energy photons for the ALS macromolecular crystallography beamline, Gemini. The undulator is a hybrid design with a minimum gap of 4.3 mm, a magnetic period of 15 mm, and a photon energy range of 5–19 keV. When the device was commissioned in the ALS storage ring, it had a negligible impact on ring operations. Recently, there has been a measured degradation in storage ring performance correlated with the Leda gap. Prior to conducting an invasive magnetic measurement, we performed a suite of beam-based measurements to characterize Leda. Herein, we detail these measurements and share them with the accelerator community, who may find them useful when encountering similar challenges.
Paper: TUPS094
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPS094
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025
TUPS135
Concrete structure and shielding in the IFMIF-DONES main building
1630
IFMIF-DONES is devoted to the irradiation of fusion materials, based on a high energy linear accelerator and a lithium-deuteron stripping reaction, creating the high intensity neutron source which simulates the damage on the 1st wall of the future fusion reactors. The core of the facility are the Accelerator, Lithium and Test Systems hosted inside IFMIF-DONES Facility, in the so-called Main Building (MB). The detailed design of this building was initiated first during the IFMIF-EVEDA activities in the framework of the Broader Approach (EU-Japan Bilateral Agreement) and pursued within EUROfusion for the development of an Early Neutron Source (WPENS). The design has evolved in which the main areas in terms of neutronics shielding are the Accelerator Vault and the Test Cell, where the nuclear reaction takes place and the materials are irradiated. Additional rooms like the Access Cell or the radwaste treatment area, are key in terms of shielding. In this work, it is presented the status of the integration into the design of the MB structure of the safety requirements from the definition of the radiation maps, neutronics studies and heavy concrete vs ordinary concrete capabilities.
Paper: TUPS135
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-TUPS135
About: Received: 27 May 2025 — Revised: 04 Jun 2025 — Accepted: 13 Oct 2025 — Issue date: 05 Nov 2025
WEPB002
Advancements in magnet power supply systems at KARA: enhancing stability, efficiency, and operational capabilities
1726
The Karlsruhe Research Accelerator (KARA) has undergone a significant modernization of its power supply infrastructure, including dipole, quadrupole and sextupole magnet systems. These updates, completed by replacing the storage ring quadrupole power supplies in summer 2024, introduce improved stability, reduced energy consumption, and advanced control capabilities. The new controls and control system integration enable new operational modes, including energy ramp-down to refill the machine or reduce radiation by dumping the beam at lower energy. This allows consecutive beam optics and collective effects testing at high beam currents without creating too high radiation losses. The upgrades to the quadrupole power supplies further support these advancements by improving compatibility with modern control systems, ensuring reliable and efficient operation, and enabling more flexible operation modes. This paper summarizes operational experience over a year and compares the performance of the new systems to the previous ones. It highlights improvements in control interfaces, reliability, and overall performance, showcasing the upgrades' benefits for KARA.
Paper: WEPB002
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPB002
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 05 Nov 2025
WEPB028
Kicker magnets for fast-switching elliptical polarized undulators beamline of the TPS
1796
The variation of polarized light is a critical characteristic of synchrotron radiation sources. To accommodate diverse user needs and enable helicity switching, a soft X-ray beamline has been designed to alternate the helicity of polarized undulator radiation. This is achieved by switching between two undulators, configured to provide right and left circularly polarized radiation, respectively. To separate and select these two circularly polarized photon beams, six kicker magnets are installed in the straight section. This paper details the design considerations, fabrication processes, and field measurement results of these kicker magnets, emphasizing their role in achieving seamless helicity switching and supporting the beamline’s functionality for cohabitation of multiple users.
Paper: WEPB028
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPB028
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 05 Nov 2025
WEPB034
Beam impact experiment to qualify the damage limits of Nb3Sn sample coils pre-irradiated to 30 MGy
1807
A series of experiments has been carried out at CERN to derive the damage limits of superconductor strands and sample coils. The latest experiment was designed to characterize the limits of Nb3Sn racetrack sample coils impacted by a 440 GeV/c proton beam at cryogenic temperature. The effect of a beam impact on superconducting coils aged by long-term radiation exposure, however, is currently unknown. This paper outlines the preparation of an experiment to be performed at the HiRadMat facility to investigate the damage on coils which have been aged with X-rays to simulate the anticipated integral dose levels reached by the HL-LHC final focusing magnets during their operational lifetime, of 25 to 30 MGy. The damage limits for these coils will be derived and compared with the results previously obtained for non-aged coils. The design and fabrication of these sample coils, the details of the X-ray irradiation and the results from their qualification tests before beam impact is discussed. The results of energy deposition simulations that define the optimal parameters for the proton beam to be used are presented. The experimental setup and procedure are discussed.
Paper: WEPB034
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPB034
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 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
WEPM063
Symmetric double-double bend lattice for a potential EUV diffraction limited upgrade of the HLS
2113
NSRL recently proposed a future plan to further upgrade the HLS to an EUV diffraction-limited storage ring, named HLS-III. In this paper, a symmetric double-double bend lattice with long and mid-straight sections is studied as a highly promising design for the HLS-III storage ring. The design achieves an ultra-low natural emittance of 2.82 nm·rad at 800 MeV, while maintaining the current eight straight sections but with significantly reduced beta functions in these straights. By minimizing the fluctuation of resonance driving terms, the nonlinear dynamics optimization yields a large horizontal dynamic aperture of about 40 mm. Additionally, error and intra-beam scattering effects are evaluated.
Paper: WEPM063
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPM063
About: Received: 08 Apr 2025 — Revised: 31 May 2025 — Accepted: 02 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
WEPM072
Computational analysis of shielding on the coherent synchrotron radiation generated by a 3D bunch
2129
The analysis and mitigation of collective beam effects, such as coherent synchrotron radiation (CSR), is a significant challenge in the generation of high-brightness beams. To this end, considerable effort has been invested in the development of simulation tools to accurately characterize the CSR generated by a bunch following a curved trajectory. In particular, with codes like LW3D and CoSyR, it is possible to model the CSR wake due to an evolving 3D bunch distribution in free space with minimal approximation. Recently, we have developed a simulation tool that self-consistently characterizes CSR through direct computation of the Liénard–Wiechert fields while accounting for the presence of shielding walls. In this work, we use this method to study the CSR shielding effect on a complex bunch moving through both a single dipole and a bunch compressor, with particular emphasis on the boundaries of validity of 1D theory in predicting the phase space evolution. This work is part of a broad effort to investigate the impact of shielding both theoretically and through a series of planned experiments at the Argonne Wakefield Accelerator (AWA).
Paper: WEPM072
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPM072
About: Received: 29 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 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
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
WEPS091
Intrabeam scattering in SRF "SKIF" storage ring
2408
SKIF (Russian acronym for Siberian Circular Photon Source) – is a new fourth generation synchrotron light source under construction in Novosibirsk, Russian Federation. One of the most important characteristics of the synchrotron radiation source SRF "SKIF", which in turn determines its brightness, is the ultra-low emittance of the electron beam, which depends on the operating regime and parameters of the storage ring: the intensity of the electron beam, the insertion devices parameters, the coupling coefficient of linear betatron oscillations, the elongation of the bunches, etc. Intrabeam scattering (IBS) is a collective effect that causes bunch volume inflation and brightness decrease for high intensity beams. Described in this work are the results of study of IBS impact on beam emittance, energy spread, Touschek lifetime and geometrical brightness for different operating regimes of the SRF “SKIF” storage ring.
Paper: WEPS091
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPS091
About: Received: 29 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025
WEPS092
Touschek lifetime and periodic beam loading effect in the storage ring of SRF "SKIF"
2411
The collective effects observed in storage rings with high-intensity beams are numerous and diverse. One such effect is that of periodic beam loading of accelerating RF cavities. This effect is contingent upon the impedance of the fundamental mode of the RF cavities and the mode of filling pattern. In a multitude of configurations, the periodic beam loading effect in storage rings leads to a change in the Touschek lifetime along the beam. This work is dedicated to the calculation of this effect in the storage ring of SRF "SKIF", a novel fourth-generation synchrotron radiation source currently under construction in Novosibirsk. Analytical calculations of this effect have been carried out for the main filling mode of the storage ring. It has been demonstrated that bunches in this regime can exhibit significantly disparate Touschek lifetimes. Furthermore, it has been shown that the effect is negligible when the RF acceptance is equal to the energy acceptance of the storage ring.
Paper: WEPS092
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-WEPS092
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 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
THPB011
Design, fabrication, and characterization of 3D-printed photonic crystals for THz filtering applications in particle accelerator
2520
The advancement of broadband terahertz (THz) sources has become increasingly important for various scientific and technological applications, including those in particle accelerators. To enable tunable and flexible THz source development, components capable of selective THz spectrum filtering are essential. In this work, we investigate the use of 3D-printed photonic crystal structures, specifically woodpile designs, for THz filtering applications. Using high-precision digital light processing (DLP) 3D printing, we successfully fabricate woodpile photonic crystals with high accuracy. The fabricated structures demonstrate effective spectral filtering capabilities within the THz range, offering promising potential for applications in advanced accelerator technology and related fields.
Paper: THPB011
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPB011
About: Received: 28 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025
THPB012
Development and laboratory validation of a precise alignment setup for electron beam-based THz radiation generation at European XFEL
2523
We present the development and laboratory testing of a precise alignment setup for the STERN experimental area at the European XFEL, aimed at exploring beam-based THz radiation generation methods using Cherenkov waveguides. The setup employs an alignment laser to simulate the electron beam trajectory, enabling the accurate positioning of critical components, such as a copper block housing dielectric waveguides. The alignment process involves scintillator screens placed before and after the vacuum chamber to measure the electron beam trajectory, with the alignment laser subsequently adjusted to replicate this path. The experimental validation focused on the reproducibility of alignment under simulated operational conditions, testing the positioning and movement of mirrors, and ensuring the stability of the alignment system for the critical components.
Paper: THPB012
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPB012
About: Received: 28 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025
THPB018
Conceptual design and optimization of a liquid lead circuit as beamstrahlung absorber for the CERN’s FCC
2540
Beamstrahlung radiation represents a new challenge at CERN's lepton Future Circular Collider (FCC-ee), specifically for electron-positron collisions. At each interaction point, its unprecedented beam intensities give rise to two photon beams with a power of several hundred kW each. Liquid lead, known for its high density and Z and relatively low melting point, is proposed as a beam dump material to safely dispose of this power. Achieving the necessary effective interaction thickness of 10 to 20 cm presents challenges in optimizing both mass flow rates and the geometric configuration of the lead. This study employs the Monte Carlo code FLUKA to simulate energy deposition and thermal simulations to investigate multiphase flow dynamics within an open-channel configuration. Various slope designs for a free-flowing liquid lead stream within an argon-filled vessel are explored to prevent oxidation. By optimizing the slope and shape of the lead flow, this work seeks to enhance energy absorption and thermal management, improving the effectiveness of liquid lead in high-power beam dump applications.
Paper: THPB018
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPB018
About: Received: 26 May 2025 — Revised: 31 May 2025 — Accepted: 05 Jun 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
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
THPB045
Permanent magnet-based dipole-quadrupole magnet for SPring-8-II
2602
In recent years, permanent magnet (PM) based multi-pole magnets have become an increasing concern as a replacement for conventional electro-magnets for light sources. The PMs are possible to save both energy and costs for operating and construction the facilities due to the absence of a power supply and cooling system. They have other advantages such as less space without magnetic coils and fewer failures than the conventional electro-magnets. PMs have specific issues, such as the adjustability of the magnetic field, demagnetization, and temperature dependence. Solutions to these issues were already confirmed with dipole structures for SPring-8-II, a major upgrade project of SPring-8 to the fourth generation. We have extended the knowledge and schemes to a dipole-quadrupole combined-function magnet (DQM) that comes in a quadrupole structure. The DQM is readily splittable into an upper and lower half for installation of a vacuum chamber. The reproducibility of the field gradient with half-splitting was less than 0.1%, which is within the required value. We report on the design and trial-manufacture of the PM based DQM.
Paper: THPB045
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPB045
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025
THPB058
Status of the low-Z SPS slow extraction electrostatic septum development
2630
The impact of high-flux protons on beam loss during slow extraction from the SPS to the North Area has been discussed, and improvements have been proposed focusing on reducing activation, lifetime reduction, and anode body distortion. The conducted studies shall demonstrate the feasibility of replacing the stainless-steel tank, flanges, and anode body with low-Z materials. A reduced-length prototype was fabricated to demonstrate mechanical, electrical, and vacuum performance. The paper presents the vacuum vessel development from the reduced-length prototype to the full-length setup, including numerical analysis. Prototype qualification tests, including vacuum performance, leak-tightness, high-voltage feedthrough performance, and deformation during evacuation, will be discussed to confirm that the tank remains within predicted non-linear buckling limits.
Paper: THPB058
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPB058
About: Received: 28 May 2025 — Revised: 30 May 2025 — Accepted: 31 May 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
THPB093
Current status of permanent magnet radiation resiliency studies at CEBAF
2664
One possible future for Jefferson Lab’s Continuous Electron Beam Accelerator Facility (CEBAF) lies in upgrading its maximum nominal energy using Fixed-Field Alternating-gradient (FFA) technology for its recirculating arcs. The current proposal aims to use permanent magnets to supply the fixed fields. One concern among reviewers is the degradation of these permanent magnets during operation due to the radiation environment in which they will be present. This work, funded by a Laboratory Directed R&D grant, aims to measure the magnet degradation in the CEBAF tunnel enclosure, and extrapolate to the energies expected from the upgrade. We present the latest results of this study, as well as plans moving forward.
Paper: THPB093
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPB093
About: Received: 27 May 2025 — Revised: 30 May 2025 — Accepted: 31 May 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
THPM002
VHEE FLASH radiotherapy: cutting-edge research at CLEAR, the CERN Linear Electron Accelerator for Research
2691
With the current availability of cost-effective and compact electron LINACs operating in the 100-200 MeV energy range, there has been a growing interest in using Very High Energy Electron (VHEE) radiotherapy (RT) for cancer treatment. A particularly intriguing aspect is the Ultra High Dose Rate (UHDR) or FLASH dose regime, which focuses on damaging cancerous cells while sparing healthy tissues. VHEE beams are well-suited for FLASH RT, given their deep penetration and high beam current, making them effective for treating large, deep-seated tumors. The CLEAR (CERN Linear Electron Accelerator for Research) facility has been at the forefront of exploring VHEE and FLASH RT, conducting numerous unique experiments in collaboration with multidisciplinary user groups having experience in dosimetric, chemical, and biological studies. This paper introduces recent measurements, techniques, and methods used to observe the FLASH effect at CLEAR.
Paper: THPM002
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPM002
About: Received: 27 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 05 Nov 2025
THPM037
Longitudinal beam size measurement at the Novosibirsk FEL
2762
The Novosibirsk Free Electron Laser (NovoFEL) is a facility that consists of three free electron laser (FEL) systems installed on different parts of the Energy Recovery Linac (ERL). These three FELs share the same acceleration system, which enables the generation of high average electron current, typically around 10 mA. Precise measurement of the electron beam parameters is essential for monitoring the performance of the accelerator and tuning its operating modes. One of the most important parameters is the length of the electron bunch, as it directly affects the efficiency of the laser radiation generation process. This paper presents the results of experiments conducted to study the behavior of the longitudinal beam size in various Novosibirsk FEL lasers. For these experiments, we used Cherenkov radiation produced by a beam of electrons passing through a thin aerogel plate. The resulting flash of radiation was captured by a streak camera, allowing us to determine the longitudinal size of the electron beam. The results of the study on the dependence of the longitudinal beam size on various accelerator parameters are presented.
Paper: THPM037
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPM037
About: Received: 27 May 2025 — Revised: 30 May 2025 — Accepted: 14 Oct 2025 — Issue date: 05 Nov 2025
THPM038
Measurement of the radiation damping time via optical methods
2766
The radiation damping time is a crucial parameter that depends on the overall magnetic structure of the accelerator. Accurate measurement of this damping time can provide insights into the fidelity of the accelerator model by allowing for a comparison with calculated damping time values. In this study, we present a series of measurements of radiation damping times at the VEPP-4M and VEPP-2000 collider at BINP. In order to determine the damping time, we recorded the transverse beam profile using a digital camera. The results includes study of the damping times at revolution frequencies and different energies of the beams.
Paper: THPM038
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPM038
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 14 Oct 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
THPM077
Measurement of vertical and horizontal emittance via undulator high harmonics at the APS-U
2852
The transition from 3rd to 4th generation synchrotron light sources can primarily be characterized by a significant reduction in horizontal emittance. This enables a nearly uniform transverse X-ray beam profile and a brilliance that approaches the diffraction limit. A consequence of the upgrade to Diffraction Limited Storage Rings (DLSRs) is that the traditional emittance measurement techniques lack the resolution required to accurately measure emittances in the picometer-radian range. At the Advanced Photon Source Upgrade (APS-U), we explore the use of high harmonics of undulator radiation for precise emittance characterization. Previously at the Advanced Photon Source (APS), vertical emittance measurements, validated through SPECTRA simulations, were performed. This drove the desire to measure the horizontal emittance at the APS-U. Simulations performed in SPECTRA and Synchrotron Radiation Workshop (SRW) guide our experimental strategy for characterization. We present measurements of both the horizontal and vertical emittance at the APS-U, including variations across different bunch timing modes. We conclude by discussing the advantages of this approach over traditional methods.
Paper: THPM077
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPM077
About: Received: 28 May 2025 — Revised: 31 May 2025 — Accepted: 05 Jun 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
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
THPS007
Oxygen deficiency detection in the LHC
2952
With the increased performance of the High Luminosity Large Hadron Collider (HL-LHC), gas leak detection in the vicinity of the superconducting magnets cooled with cryogenic helium becomes a challenge. To ensure operational safety and reliable detection of Oxygen Deficiency Hazard (ODH) for the next decade, the entire system will be refurbished during the LHC accelerator's long shutdown, scheduled to begin in 2026. The new design of the ODH detection system includes development of a detector and flashing lights that can not only cope with electromagnetic disturbances, but also with an increased radiation exposure, all while considering the restricted access for equipment maintenance. Understanding the nature and impact of these constraints at the design stage is key to specifying the requirements of the new safety systems. This paper describes the research and development work undertaken by CERN to analyse, test, and define oxygen deficiency detection taking into account lessons learned from the current systems and the future upgrade to the High Luminosity LHC.
Paper: THPS007
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPS007
About: Received: 19 May 2025 — Revised: 05 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
THPS024
Radiation monitoring and R2E performance in the LHC during the 2024 proton run
3006
The integrated luminosities in each of the ATLAS and CMS experiments at the Large Hadron Collider (LHC) have reached above 120 fb-1 during the proton run of 2024, the highest annual values since the beginning of the LHC operation. The same is true for LHCb, with over 10 fb-1 of integrated luminosity reached during proton operation in 2024. Such high levels of integrated luminosity are associated with high levels of radiation around the experiment locations, including hundreds of meters of tunnel on both sides of the interaction point, where beam losses driven by the luminosity production still occur. The ability of the LHC systems to operate in the radiation environment of the machine is analyzed in this contribution. Each year, radiation effects on electronic components installed around the LHC lead to premature beam dumps, causing accelerator down-time and loss of physics production. The number of radiation-induced beam dumps of the proton run 2024 per integrated luminosity has been comparable to previous years in LHC Run 3, and improved compared to LHC Run 2. However, due to the large integrated luminosity of LHCb, a large part of the events have been observed there, and some mitigation strategies to minimize such events are discussed.
Paper: THPS024
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPS024
About: Received: 27 May 2025 — Revised: 02 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 05 Nov 2025
THPS025
Passive Radiation Detection Using TLD in NSRRC
3010
The NSRRC is a research facility and currently op-erates two synchrotron accelerators: the Taiwan Light Source (TLS), featuring a beam energy of 1.5 GeV and a circumference of 120 meters, and the Taiwan Photon Source (TPS), with a beam energy of 3 GeV and a cir-cumference of 518.4 meters. There are hundreds of users in 40 beamlines among TPS and TLS experi-mental floors. The Thermo-Luminescent Dosimeter (TLD) is a compact instrument utilizing well-established detec-tion technology. To ensure radiation intensity at NSRRC workplace as close to background radiation levels as possible, we have deployed approximately 200 TLDs among these two accelerators. For each BL, three points are selected: the optical hutch near accel-erator shielding wall, the user experimental area with the highest occupancy, and the BL rear end. Additional TLDs are strategically placed around the accelerator's surroundings, including both the outer and inner sur-face of the shielding tunnel, downstream of the injec-tion section, the roof and downstream area of the RF cavities. In this paper, we will present the detection data col-lected at NSRRC over the past several years to reflect the proficiency of our radiation protection program.
Paper: THPS025
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPS025
About: Received: 06 May 2025 — Revised: 02 Jun 2025 — Accepted: 14 Oct 2025 — Issue date: 05 Nov 2025
THPS103
Optical electron beam diagnostics at the Novosibirsk FEL
3170
We present an overview of recent and upcoming enhancements to the optical electron beam diagnostics stations at the Novosibirsk Free Electron Laser (FEL) facility. These diagnostic stations are designed to measure key beam parameters, including beam energy spread, length and emittance, at the third FEL of Novosibirsk FEL. Currently, the stations for measuring electron beam energy spread and undulator radiation spectrum are in the commissioning phase, with initial results already obtained. The new optical diagnostics are essential for the precise tuning of the magnet system used in electron outcoupling experiments. This paper provides a comprehensive overview of the new diagnostic systems, discusses the preliminary measurement results of beam parameters, and outlines the experiments planned for the near future.
Paper: THPS103
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPS103
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 05 Nov 2025
THPS104
Development and testing of an autocorrelator for measuring the duration of picosecond pulses of near infrared radiation
3174
The paper presents a design of an autocorrelator manufactured to measure the duration of infrared picosecond pulses of radiation from the 3rd laser of the Novosibirsk Free Electron Laser facility, as well as the results of testing the autocorrelator when measuring the duration of picosecond pulses in the visible range. The results and future plans for future experiments using developed autocorrelator
Paper: THPS104
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPS104
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025
THPS107
Substrate material studies for PCB-based electro-optical bunch arrival-time monitors for XFELs
3181
The all-optical synchronization system used in many X-ray free-electron laser facilities (XFELs) relies on electro-optical bunch arrival-time monitors (EO-BAM) for measuring the single bunch arrival time with regards to an optical reference. An upgrade of the established EO-BAM is intended to achieve a sensitivity that enables stable operation with bunches down to charges of 1 pC, or to significantly increase the resolution in normal operation. Therefore, the pickup structure, the RF path and the electro-optical modulators are undergoing a fundamental redesign. The novel concept of the pickup structure comprises planar pickups on a printed circuit board (PCB) with integrated combination network and a bandwidth of up to 100 GHz. The theoretical jitter charge product of the preliminary concept has been estimated to be in the order of 9 fs pC and the concept was proven experimentally with a 67-GHz demonstrator at ELBE. In this contribution, we compare ceramic and glass substrates in terms of radiation hardness, sensitivity, and manufacturing capabilities. The achievable bandwidth and sensitivity are influenced by material losses and varying tolerances due to different fabrication methods.
Paper: THPS107
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPS107
About: Received: 28 May 2025 — Revised: 31 May 2025 — Accepted: 03 Jun 2025 — Issue date: 05 Nov 2025
THPS110
Advancing accelerator science through data-intensive research and training
3193
The Liverpool Centre for Doctoral Training in Innovation in Data Intensive Science (LIV.INNO) has made significant progress in applying data-intensive methods to accelerator research. This contribution presents research outcomes from the center with a focus on two key projects. The first focuses on optimizing 3D imaging for medical and industrial applications, integrating Monte Carlo simulations and advanced collimation techniques to enhance low-dose, portable X-ray systems, with implications for wider accelerator diagnostics. The second lever-ages deep learning models to reconstruct transverse beam distributions at CERN, addressing challenges in image distortion from multimode optical fibers under high-radiation conditions. The results are connected with wider progress made in machine learning and artificial intelligence for particle accelerators. Furthermore, the paper summarizes the outcomes of several key LIV.INNO events: the STFC Summer School on Data Intensive Science, the LIV.INNO 2024 Industry Showcase and the 2025 AI for Innovation Summit.
Paper: THPS110
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPS110
About: Received: 28 May 2025 — Revised: 31 May 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025
THPS124
Modernization of the automated radiation monitoring system for the U400M cyclotron and the main building at FLNR
3213
Currently, the Flerov Laboratory of Nuclear Reactions (FLNR) is modernizing its accelerator complex, focusing on the development of new facilities and the enhancement of existing ones. Notably, the U400M cyclotron has been successfully modernized. As part of the upgrade of the U400M's main systems, a project for the deep modernization of its Automated Radiation Monitoring System (ARMS) was initiated. In addition to monitoring the radiation environment of the U400M, the ARMS oversees other radiation-related facilities in the main building at FLNR. These include the MT-25 microtron, radiochemical laboratories of the 2nd and 3rd safety classes, and the radioactive isotope storage facility. This report presents the main types of radiation monitoring implemented by the system, the equipment used, its software features, and the interaction algorithms with the control systems of the U400M and MT-25 accelerators, as well as the U400M Interlock and Signalization System (ISS). Additionally, the current status of the project, challenges in its commissioning, and the prospects for further development of the system at FLNR are discussed.
Paper: THPS124
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPS124
About: Received: 22 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 05 Nov 2025
THPS125
Design and development of AR RF personnel protection and interlock system for RF Test with Access mode to RF cavities in ALS-U project at LBNL
3216
The ALS-U project at LBNL is a major upgrade of the ALS involving a new Accumulator Ring (AR) and an upgraded Storage Ring (SR). The new AR RF System has one operational mode with beam and three test modes without beam. Another upgraded overarching Ring Personnel Protection Systems (PPS) covering both AR and SR ring enclosure areas is in place for personnel protection from ionizing radiation during beam operation and it is interfaced with AR RF PPS subsystem for status & control signals. In the RF Test with Access mode, the controlled access of authorized personnel is permitted to AR RF cavities area when it is powered below certain predetermined power limit without beam, for conducting low power RF leakage checks, tests. For that objective, an AR RF PPS power monitor & interlocks as described in this paper has been designed & developed for use in the Test with Access mode in order to ensure that potential exposure to harmful ionizing X-rays from RF cavity operating does not result in doses above the prescribed limits. The actual X ray dose rate data will also be experimentally surveyed at various RF cavity power levels. This paper presents the design features, circuits and construction of such AR RF PPS subsystem for accurately monitoring RF Cavity power and to break the interlocked chain to turn OFF the RF input drive to AR RF High Power Amplifiers (HPA) feeding RF cavities, if the RF cavity power exceeds such pre-determined power limits.
Paper: THPS125
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPS125
About: Received: 27 May 2025 — Revised: 02 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 05 Nov 2025
THPS127
Design of RF duct shielding for the SPS-II 3-GeV electron storage ring
3219
The Siam Photon Source II (SPS-II) is a fourth-generation synchrotron light source designed to provide high-brightness, low-emittance, high-energy electron beams for advanced synchrotron applications. SPS-II is equipped with a 150-MeV linear accelerator, a 3-GeV booster synchrotron, and a 3-GeV electron storage ring, enabling the production of high-quality synchrotron radiation for a wide range of scientific research fields. The 500 MHz RF system in the storage ring serves to replenish the energy lost by electrons due to synchrotron radiation. RF cavities generate oscillating electromagnetic fields at a specific frequency, accelerating the electrons each time they pass through the cavity. The RF ducts house the waveguides and transfer RF power to the RF cavities inside the storage ring tunnel. However, penetration in the storage ring tunnel may allow radiation within the shielding tunnel to leak outside the shielding. For this reason, the design of the RF ducts must be carefully considered. The FLUKA particle transport code is used to investigate the shielding. The results indicate that the radiation dose is below the design criterion, meeting the radiation safety standards.
Paper: THPS127
DOI: reference for this paper: 10.18429/JACoW-IPAC2025-THPS127
About: Received: 27 May 2025 — Revised: 30 May 2025 — Accepted: 30 May 2025 — Issue date: 05 Nov 2025