WEPB
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Wednesday Poster Session: WEPB
04 Jun 2025, 16:00 -
18:00
HEPS Magnet power supply with magnetization and demagnetization functions
After the magnet is magnetized, due to the characteristics of the magnetization curve, there will still be residual magnetism in the magnetic field even after the magnetizing power supply is turned off. When measuring the same magnet multiple times, the residual magnetism not only affects the measurement of the magnetization curve but also impacts surrounding devices and instruments. In the magnetic measurement work prior to the installation of the magnet, it is sometimes necessary to demagnetize the already magnetized magnet. The magnetic measurement power supply described in this article can operate in both magnetization and demagnetization modes, where the magnetization mode provides a DC current with high stability for magnetization, and the demagnetization mode automatically demagnetizes the magnet.
WEPB002
Advancements in magnet power supply systems at KARA: enhancing stability, efficiency, and operational capabilities
1691
The Karlsruhe Research Accelerator (KARA) has undergone a significant modernization of its power supply infrastructure, including dipole, quadrupole and sextupole magnet systems. These updates, completed by replacing the storage ring quadrupole power supplies in summer 2024, introduce improved stability, reduced energy consumption, and advanced control capabilities. The new controls and control system integration enable new operational modes, including energy ramp-down to refill the machine or reduce radiation by dumping the beam at lower energy. This allows consecutive beam optics and collective effects testing at high beam currents without creating too high radiation losses. The upgrades to the quadrupole power supplies further support these advancements by improving compatibility with modern control systems, ensuring reliable and efficient operation, and enabling more flexible operation modes. This paper summarizes operational experience over a year and compares the performance of the new systems to the previous ones. It highlights improvements in control interfaces, reliability, and overall performance, showcasing the upgrades' benefits for KARA.
Paper: WEPB002
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB002
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
Cryocooler-based conduction cooling for 1.3 GHz Nb3Sn superconducting RF cavity
Superconducting radio frequency (SRF) cavities are, along with superconducting magnets, indispensable technologies for modern particle accelerators. The current cooling method for SRF cavities is immersion in liquid helium bath, which is ideal in terms of cooling because the entire outer surface of the cavity can be maintained at liquid helium temperature. On the other hand, using helium has several difficulties such as costs, availability, large facilities, and high pressure gas safety. Conduction cooling for SRF cavities are currently widely focused all over the world to sweep away above problems. KEK is pushing conduction cooling technology development for 1.3 GHz Nb3Sn cavity towards beam acceleration. We have ever done several RF tests under conduction cooling by cryocoolers and copper rings on the cavity equator. In the poster, we will introduce our progress and future plan.
Development status of a NbTi conduction-cooled superconducting quadrupole magnet combined with dipole correctors for the ILC main linac
In the International Linear Collider (ILC) main linac, superconducting quadrupole (SCQ) magnets combined with dipole correctors, together with superconducting radio frequency (SRF) cavities, will be used to transport and accelerate electron and positron beams to the collision point. The SRF cavity accelerates the beam up to 125 GeV per side, the SCQ focuses the beam, and the dipole collectors steer the beam and transport it along with the geoid. A 5-year plan to manufacture one ILC-type cryomodule began at KEK in 2023 with international collaboration. A prototype SCQ is being manufactured currently. It consists of 4 sets of race-track coils and each set has three coils for quadrupole, vertical dipole, and horizontal dipole. An excitation test will be performed at cryogenic temperature with a newly fabricated stand-alone test cryostat by March 2026. In the poster, the status of SCQ fabrication and the stand-alone test cryostat will be reported.
WEPB007
Operation status of superconducting RF system in SuperKEKB with high beam current
1695
SuperKEKB continues the operation with the aim of achieving high luminosity. The beam current has already exceeded 1.3 A in the electron ring and 1.6 A in the positron ring. Eight superconducting RF (SRF) systems are operating in the electron ring. The SRF system including cavities, input couplers, HOM dampers, and so on was designed for KEKB and modified to handle the higher beam current of SuperKEKB. The SRF system is operating stably without any major problems. There are many issues that need to be resolved, such as large beam power and HOM power increasing with beam current, and various risks of failure due to aging of the system. To maintain stable SRF system operation, it is essential to establish an anomaly detection system and methods for assessing and recovering system performance. We will report on the operating status of the SRF system in the high beam current and countermeasures for the issues.
Paper: WEPB007
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB007
About: Received: 27 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
WEPB008
Higher order mode power in superconducting cavities of SuperKEKB with high current operation
1699
SuperKEKB is a high-current machine for high-luminosity.Eight higher order mode (HOM) damped single-cell superconducting cavities accelerated an electron beam in the main ring since KEKB. A strong dependence of the absorbed power of the ferrite HOM dampers on the number of bunches was observed in 2022 operation. One of the reasons for this is thought to be a build-up effect of some parts of the HOM caused by narrow bunch spacing. It was found in the last operation that this problem has an individual difference for each cavity. In particular, TM011 can propagate on the LBP side, and the frequency is quite close to an integer multiple of the RF frequency, the build-up effect is remarkable. As the accelerator is expected to reach its design current in the future, the HOM power will also increase and ferrite HOM dampers will have to cope with the increasing HOM power resulting from the build-up. This report provides an overview of the status of the superconducting cavity HOMs last operation in 2023-2024 and a countermeasure plan for the future.
Paper: WEPB008
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB008
About: Received: 26 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
WEPB009
Superconducting β=0.19 half-wave cavity for CiADS
1703
A 162.5 MHz, optimal beta = 0.19 pure niobium half-wave resonator (HWR) called HWR019 for the superconducting driver linac of the China initiative Accelerator-Driven subcritical System (CiADS) has been designed and analyzed at the Institute of Modern Physics, Chinese Academy of Sciences (IMP, CAS). The linac requires 24 HWR019s to accelerate protons from 6.8 MeV to 45 MeV. This paper mainly presents a design scheme of HWR019. Meanwhile, electromagnetic field optimization, and mechanical structure design are carried out, to predict the behavior of the cavity under practical operating process. At present, this superconducting cavity has been fabricated a prototype and awaits further testing.
Paper: WEPB009
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB009
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
WEPB010
RF design for a quadrupole resonator with a fundamental frequency of 325 MHz at IMP
1706
The Quadrupole Resonator (QPR), originally developed at CERN, is a dedicated radio-frequency characterization equipment for evaluating superconducting material. It employs the calorimetric compensation technique and has a surface resistance resolution of less than 1 nOhm, operaing over a wide range of parameters, such as tem-peratures, resonant frequencies and magnetic fields. As a part of R&D work of superconducting material for SRF application in particle accelerators. A QPR with operating frequency of 325 MHz has been developing at Institute of Modern Physics (IMP), CAS. In this paper, we present the detailed electromagnetic design of the QPR, the design focuses on reducing the risk of multipacting, field emis-sion (B<sub>pk</sub>/E<sub>pk</sub>) and mode overlapping (delta f = f<sub>QPR</sub>-f<sub>dipole</sub>), enhancing the attainable peak magnetic field (B<sub>sample</sub>/B<sub>pk</sub>). The electromagnetic simulation results indicate that the optimized structure has good electromagnetic performance. Additionally, the coupler design compatible with four QPR modes will be introduced. The cavity will be fabricated soon.
Paper: WEPB010
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB010
About: Received: 09 Apr 2025 — Revised: 31 May 2025 — Accepted: 31 May 2025 — Issue date: 06 Jun 2025
Recent progress in the coating and application of Nb3Sn thin film SRF cavity at IMP
Systematic research work including coating process optimization of Nb3Sn thin film on single cell cavity, quality control before and after coating Nb3Sn thin film on multi-cell cavity, and the construction and operation of LHe-free Nb3Sn SRF demo electron accelerator was carried out at IMP. The evolution of Nb3Sn thin films in the whole growth cycle was tracked by experiments, and the mechanism of the oxide layer on the uniform growth of Nb3Sn thin films was clarified by theoretical calculation. Field flatness of the Multi-cell cavity during different post-treatments involving long-distance transport, handling and lifting, light BCP polishing, disassembly, reassembly and coating has been verified. The one-year operation experience of LHe-free Nb3Sn SRF demo electron accelerator will be shared. In addition, the experiment of degradation of wastewater by electron beam irradiation was carried out based on the Nb3Sn SRF electron accelerator.
Status of the RF system design for the SC240 cyclotron
The superconducting cyclotron SC240 is used to accelerate proton beams to 240 MeV for proton therapy. The SC240 is an isochronous 4 sectors compact cyclotron with a central magnetic field of 2.5 T. Particles acceleration is performed under the second harmonic mode of the radio-frequency (RF) system, consisting of two independent cavities located in the cyclotron valleys. Block on the chimney is designed to avoid interference between two cavities. The isolation (S21) is less than -30dB. In cavities, two types of tuners applied to compensate for frequency offset are tuning loop and trimmer plate. The tuning frequency range of tuning loop is more than 1MHz, that can be used to adjust the frequency offset caused by machining error and installation error during cold test, rather than caused by thermal deformation when feeding high power into cavities, While the trimmer plate is just used in the opposite way. Efficiency of acceleration voltage in center region caused by different ground position of ion source is presented in the paper. Design and optimization of inductive coupler are described in details. Besides, the current operating status of the RF system will also be discussed.
WEPB013
Thermal analysis for the fundamental power coupler of the 197 MHz crab cavity for EIC
1710
The Electron-Ion Collider (EIC) is being designed by BNL in collaboration with Jefferson Lab. The Phase-I design includes the installation of two cryomodules of 197 MHz crabbing cavities installed at the Hadron Storage Ring (HSR) at the interaction region, IP6 that has a crossing angle of 25 mrad. Each cryomodule consists of two 197 MHz RFD type crabbing cavities. The first article cavity has been designed following the machine requirements and specifications including the fundamental power coupler (FPC), higher order mode couplers, and field probes. A detailed rf analysis has been completed to determine the worst operational case of the FPC. Next, the thermal analysis was carried out to design the warm-to-cold section of the FPC. This paper presents the detailed rf and thermal analysis of the 197 MHz first article crabbing cavity.
Paper: WEPB013
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB013
About: Received: 03 Jun 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
WEPB014
Sensitivity analysis of the 197 MHz prototype crab cavity for EIC
1714
The Electron-Ion Collider at BNL requires several crabbing systems that will be operating at 197 MHz and 394 MHz to compensate for the loss of luminosity due to the large crossing angle of the colliding beams. Two 197 MHz crab cavity cryomodules containing two cavities each will be installed in the Hadron Storage Ring (HSR) at the IP6 interaction region. Due to its large size compared to previously developed crabbing cavities, the 197 MHz crabbing cavity system was identified as one of the critical rf systems in the EIC. Therefore, a cavity has been designed including the ancillaries, and is in the fabrication process, in-house at Jefferson Lab. This cavity will be used to verify the required performance of the first 197 MHz crabbing cavity. Detailed tolerance analysis has been carried out considering cavity operating frequency and HOMs. This paper presents the results from the study in comparison with the achieved tolerances during the fabrication of cavity components.
Paper: WEPB014
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB014
About: Received: 04 Jun 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
WEPB015
Multicell parameterisation for sensitivity analysis and uncertainty quantification of elliptical accelerator cavities
1718
Elliptical cavity geometries are typically parameterised using a canonical set of variables that define the shape of the cavity half-cells. In multicell cavity optimisation, the mid-cells are modelled with identical dimensions, while the end-cells are optimised to ensure good field flatness. However, manufacturing tolerances can introduce slight variations between individual half-cells, as cavities are produced with separate dumb-bells, which are thereafter welded together. To address these variations, a multicell parameterisation is proposed, where each half-cell is defined by its own set of variables. This parameterisation method offers a more accurate representation of real-world cavity geometries and facilitates a detailed analysis of the impact of geometric uncertainties on cavity performance. A sensitivity analysis is presented to quantify the influence of each independent geometric variable on key performance metrics, providing valuable insights for optimising both cavity design and manufacturing processes.
Paper: WEPB015
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB015
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
First magnetic field penetration results of multilayer samples and A15 materials for the use in SRF applications
Superconducting radiofrequency cavities made of bulk Nb are reaching their theoretical limits in the maximum accelerating gradient, Eacc, where Eacc is limited by the maximum magnetic field, B, that can be applied on the surface of the accelerating cavity wall. To increase Eacc, the maximum B field, Bmax, which can be applied to the surface, must also be increased. The A15 materials or multilayer structures are the potential solution to increase Bmax., Since coating and RF testing of full size RF cavities is both expensive and time consuming, one need to evaluate new ideas in superconducting thin films quickly and at low cost. A magnetic field penetration experiment has been designed and built at STFC Daresbury Laboratory to test superconducting samples (< 100 mm ). The facility produces a parallel DC magnetic field, which applied from one side of the sample to the other similar to that in an RF cavity. The facility applies an increasing magnetic field at a set temperature to determine the field of full flux penetration which can give an insight into the quality and structure of the superconducting structure.
Identifying the connections between grain growth and flux expulsion in low RRR niobium SRF cavities
The SRF community has shown that high temperature annealing can improve the flux expulsion of niobium cavities during cooldown. The required temperature will vary between cavities and different batches of material, typically around 800 C and up to 1000 C. However, for niobium with a low residual resistance ratio (RRR), even 1000 C is not enough to improve its poor flux expulsion. The purpose of this study is to observe the grain growth behavior of low RRR niobium coupons subjected to high temperature annealing to identify the mechanism for improving flux expulsion. We observe that low RRR material experiences less grain growth than high RRR when annealed at the same temperature. We search for the limitations to grain growth in low RRR material and develop a diagnostic based on grain structure to determine the appropriate recipe for good flux expulsion. The results of this study have the potential to unlock a new understanding on SRF materials and enable the next generation of high Q/high gradient surface treatments.
WEPB018
ESS RF power station (400 kW @ 352 MHz) for spokes: issues identified due to soak testing and operational insights
1722
The first section of the ESS superconducting linac is the Spoke Linac, which raises the beam energy from 90 MeV to 216 MeV. This is achieved by 26 superconducting spoke cavities, housed in 13 cryomodules. These cavities are powered by Spoke RF Power Stations (RFPS), each delivering a maximum power output of 400 kW at 352 MHz. This power is generated by combining the outputs of two tetrode TH595A-based amplifiers using a hybrid combiner. The RFPS units are supplied by Elettra as part of Italy's in-kind contribution to the ESS. To date, 27 RFPS units have been delivered to ESS, with 26 installed and commissioned in the ESS gallery. The RFPS units have been utilized to test and qualify various systems. The interfaces for the Personal Protection System (PSS) and the Machine Protection System (MPS), both critical for beam operation, have also been successfully validated. Additionally, the RFPS units were employed in the warm and cold coupler conditioning of the spoke cavities. They will continue to be used for cold cavity conditioning and beam commissioning. This paper addresses the issues identified during soak testing and the corresponding mitigations that were implemented.
Paper: WEPB018
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB018
About: Received: 29 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
Upgrade of low-level RF system for J-PARC linac RFQ-TS
The radio-frequency quadrupole test stand (RFQ-TS) was prepared for conditioning the spare RFQ in the J-PARC Linac. Additionally, the RFQ-TS is used for the development of accelerator components and the acquisition of beam parameters. The digital feedback system of the Low-Level RF (LLRF) in the RFQ-TS was previously using the discontinued cPCI system, which had been in use for 20 years since its development. In order to continue improvements of the RFQ-TS and to allow for future development, the system has been upgraded to use $\mu$TCA.4-based system, which can be developed further. In this presentation, we will report the details of the upgrade, as well as the feedback and feedforward adjustments.
WEPB020
Highly stable pulse operation of 476 MHz solid-state amplifiers with a precision of 0.01 degrees at SACLA
1725
We have introduced new 476MHz solid-state pulsed amplifiers to the X-ray Free Electron Laser facility, SACLA. The 476 MHz booster cavity requires high stability and reliability with a 100 kW power for 50 us pulse width. Previously, an Inductive Output Tube (IOT) was employed for this purpose. However, due to the reduced operational range caused by aging of IOT components and increasing difficulties in obtaining maintenance parts, a transition to solid-state amplifiers has been undertaken. The modular configuration of solid-state amplifiers with a combiner allows continuous operation even in the event of module failures and facilitates easy repairs. Additionally, their design eliminates the need for high voltage, as required by IOTs, which is expected to improve fault tolerance. This poster presents the operational status of the solid-state amplifiers, along with evaluation results of pulse-by-pulse stability with a precision of 0.01% for the amplitude and 0.01 degrees for the phase, respectively.
Paper: WEPB020
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB020
About: Received: 27 May 2025 — Revised: 31 May 2025 — Accepted: 31 May 2025 — Issue date: 06 Jun 2025
WEPB021
Design of a 2300 W 352 MHz solid-state amplifier module with integrated EtherCAT interface for monitoring and control
1728
For multi-unit RF amplifier systems, a 2300 W solid-state RF power amplifier module with integrated EtherCAT and USB interface has been developed. The RF amplifier section is constructed from the latest LDMOS from Ampleon with a power of 2300 W at an efficiency of 72 % and is fully shielded and offers space for adding a driver amplifier or phase shifter circuit. The module is equipped with a DIN 7/16 output connector and an N-type input connector and is housed in a metal housing of 200 x 95 x 80 mm. The cooling of the RF LDMOS is done via a CNC milled copper cooling plate that is gold-plated. The gold layer prevents chemical oxidation with other aluminum parts such as an aluminum main plate. In a multi-unit system, the EtherCAT interface provides lightning-fast and synchronous control and monitoring of parameters such as supply voltage and current, heat sink and LDMOS temperature, forward and reverse RF power. Outside the EtherCAT environment, the USB interface can be used in combination with a Windows GUI. Eight LEDs are available as visual indicators. The entire process of design, assembly and testing takes place in the Netherlands, which guarantees quality and traceability.
Paper: WEPB021
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB021
About: Received: 16 Apr 2025 — Revised: 30 May 2025 — Accepted: 01 Jun 2025 — Issue date: 06 Jun 2025
WEPB022
Design and Implementation of a Power Monitoring and Distribution System for the SSPA-Based RF Transmitter at NSRRC
1732
This paper presents the design and implementation of a power distribution and monitoring system for a high-power RF solid-state amplifier (SSPA) system at the Taiwan Photon Source (TPS). The system consists of four SSPA towers delivering a combined RF power of 300 kW. Given efficiency and safety considerations, a robust distribution and protection architecture was implemented. The system features remote monitoring and control via a Modbus-connected PLC and HMI, enhancing reliability and operational insight.
Paper: WEPB022
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB022
About: Received: 26 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
WEPB023
Transitional solution of solid-state power amplifier at NSRRC
1734
The Taiwan Photon Source (TPS) of the National Synchrotron Radiation Research Center (NSRRC) in Taiwan has integrated Solid-State Power Amplifiers (SSPAs) into routine operations since 2023, supporting a stored beam current of 500 mA. In response to the phasing out of Ampleon's BLF578 and the growing demand for improved energy efficiency, a new SSPA was developed based on the existing module configuration, utilizing the BLF978P as an interim solution. This approach serves as a bridge while the development of the next-generation SSPA, employing GaN transistors, is still underway. Both SSPA configurations, with and without circulators, were explored during development. This paper presents the performance of the prototypes and the implementation details.
Paper: WEPB023
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB023
About: Received: 28 May 2025 — Revised: 31 May 2025 — Accepted: 31 May 2025 — Issue date: 06 Jun 2025
WEPB024
Linear weight optimization of local magnetic field sensors for the integral field measurement in accelerator magnets
1737
The measurement of the integral magnetic field in accelerator magnets is crucial for the precise control and operation of particle accelerators. Traditional methods often rely on a fixed distribution of magnetic field sensors or long integral coils. Nonetheless, integral coils are sometimes unavailable in the magnet bore. This study presents an approach to enhance integral magnetic field measurements through the linear weight optimization of local magnetic field sensors. Our methodology involves strategically placing and weighing sensors within the magnet to minimize errors between the measured and actual integral magnetic fields for different powering cycles. We employ optimization algorithms to determine the optimal linear combination of sensor readings that best approximates the integral field. This process improves measurement accuracy and reduces the number of required sensors. We validate our approach through simulation and experimental setups. The results indicate that our optimized sensor placement and weighting scheme can be effectively implemented in existing accelerator systems, offering a scalable solution for enhancing particle accelerator performance.
Paper: WEPB024
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB024
About: Received: 28 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
WEPB025
The study of the eddy current-type septum magnet for fast extraction in J-PARC MR
1741
The eddy current type septum magnets (Eddy-septa) are used for fast extraction in J-PARC MR from 2022. Currently, the operation of the Eddy-septa is very stable. However, we have some still technical issue. One is an output pulsed current measurement by current transfers. The peak value of the output pulsed current is measured pulse by pulse and the measured value is used for a feedback system using by PXI system for long-term stability. The output current is also measured with different current transfer in same time for double checking. However, we don't have good reproducibility with the measurement result by the PXI feedback system yet. We have found the noise which are generated by the kicker magnets and extraction beam in 2023, thus, we started to investigate the detail of the process of generation and method of removal. Second is residual field along the circulating beam line in Eddy-septa. We had reported the leakage field by exciting current on the circulating beam line and the strength was very small. In summer of 2023, we found large residual field on the same line. In this presentation, we report the status of measurement of output current, and residual field.
Paper: WEPB025
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB025
About: Received: 27 May 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
WEPB026
Magnetic design of the cSTART magnets
1745
The KIT project cSTART (compact STorage ring for Accelerator Research and Technology) aims to store ultra-short electron bunches in a very-large-acceptance compact storage ring. The magnetic lattice of the storage ring is laid out for a variety of beam optics, including ultra-low positive and negative alpha as well as isochronous optics. These put high demands on the magnet quality and alignment. The spatial constraints for the storage ring impose further challenges on the magnet design. In this contribution, we give an overview of both the challenges and solutions for the cSTART storage ring magnet design.
Paper: WEPB026
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB026
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
WEPB027
Compact quadrupole-sextupole magnet units for the FLUTE-cSTART injection line
1749
One of the major goals of the cSTART project (compact STorage ring for Accelerator Research and Technology) at KIT is injecting and storing ultra-short bunches from the FLUTE linac into a very large-acceptance compact storage ring. To cope with the spatial constraints of the injection line connecting FLUTE with the storage ring three meters above, compact quadrupole-sextupole magnet units were designed, fabricated, and characterised. In this contribution, we describe the magnetic design of these units and the underlying considerations, particularly with respect to cross-talk effects and their mitigation by design. We present the results of rotating coil and Hall probe measurements validating the magnetic design.
Paper: WEPB027
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB027
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
WEPB028
Kicker magnets for fast-switching elliptical polarized undulators beamline of the TPS
1753
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-IPAC25-WEPB028
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
WEPB029
Transient finite-element simulations of fast-ramping normal-conducting magnets for a 10 TeV muon collider
1756
Ongoing conceptual studies for a 10TeV muon collider identified rapid cycling synchrotrons as major engineering challenge. Due to the muon’s short lifetime of only 2.2µs at rest, normal-conducting bending magnets with field rise rates of well beyond 1kT/s are indispensable to support accordingly fast acceleration cycles. Energies of 100MJ will be interchanged between magnets and capacitor banks within few milliseconds. Accurate models of the magnets are thus required to optimize the overall system performance. The non-uniform temperature distribution in the magnet strongly affects material properties like the electrical conductivity of copper and must therefore be considered in the electromagnetic field problem. This contribution presents recent advancements in addressing this multi-physical problem by using problem-specific finite-element tools allowing to describe the inherently transient behavior. The ferromagnetic yoke is accurately resolved by using a novel combination of a Bergqvist hysteresis and a homogenized eddy current model. Finally, different magnet design concepts are compared in terms of material costs, magnetic energy, losses, field quality and temperature buildup.
Paper: WEPB029
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB029
About: Received: 22 May 2025 — Revised: 31 May 2025 — Accepted: 31 May 2025 — Issue date: 06 Jun 2025
WEPB030
Efficient nonlinear simulations of the fast corrector magnets for PETRA IV
1760
Fast orbit feedback systems are an important component in fourth-generation synchrotron radiation sources such as PETRA IV at DESY in Hamburg, Germany. These control systems are designed to stabilize the particle orbit, i.e., to correct deviations from the design orbit due to various disturbances. To that end, such a system employs fast orbit corrector magnets, which must be powered at frequencies up to the kilohertz range. This leads to significant eddy current effects that must be predicted via finite element simulations. Therefore, extensive simulation studies have already been conducted. These simulations did not, however, consider the magnetization curve’s nonlinearity since doing so requires prohibitive computational effort when using commercial software. Hence, we have constructed a dedicated method, based on a combination of the harmonic balance finite element method and homogenization schemes, to enable nonlinear simulations. This contribution outlines the general idea and application of our method to the corrector magnets of PETRA IV and presents the most important findings regarding the impact of the nonlinear magnetization curve on the magnet’s performance.
Paper: WEPB030
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB030
About: Received: 05 May 2025 — Revised: 30 May 2025 — Accepted: 30 May 2025 — Issue date: 06 Jun 2025
Measurement of magnetic field characteristics using the stretched wire system
In order to explore an efficient and accurate method for measuring the magnetic field information of accelerator magnets, this paper used the stretched wire system to measure a quadrupole magnet prototype of Hefei Advanced Light Source. In the measurement process, the integral field of the magnet at multiple points was first measured to calculate the magnetic center and multipole components of the magnet, and the influence of various measurement methods on the multipole components of the magnet was explored. Furthermore, the method of measuring magnet deflection angle using the stretched wire system and the method of correcting multipole components through magnet deflection angle were explored. The measurement results indicate that the stretched wire system has sufficient functionality and accuracy to measure the magnetic field information of the magnet.
Progress on the design of solenoids for the 6D cooling channel of a muon collider
In the current and most evolved design concept of a muon collider, there exists two long (~1 km) channels for cooling newly created muons and anti-muons. Termed the `6D cooling channels', the beam is cooled in momentum and position space using a series of alternating polarity solenoids, which create an oscillating field in the beam direction, absorbers and radio-frequency cavities. In total there are around 3000 solenoids per channel, contributing to a significant portion of the cost and engineering demands of the entire machine. The integration of the requirements of the field profile with feasible solenoid configurations is a difficult and unique problem, without analytic descriptions to readily relate these. Our approach addresses this problem in two steps: in the first we constrain the beam optics optimization studies by setting engineering limits on solenoid parameters; in the second we have developed a numerical optimization routine to find the best configuration given a desired field profile, in terms of cost and engineering complexity. The following paper reviews this approach and key features,and presents optimization results on the latest optics solution.
WEPB034
Beam impact experiment to qualify the damage limits of Nb3Sn sample coils pre-irradiated to 30 MGy
1764
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-IPAC25-WEPB034
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
WEPB035
Preparing the commissioning of the HL-LHC superconducting magnet circuits: From the inner triplet string to the CERN accelerator complex
1768
The High Luminosity-Large Hadron Collider (HL-LHC) project at CERN aims to increase the integrated luminosity of the Large Hadron Collider by an order of magnitude compared to the LHC original design performance. To achieve this, the existing magnets surrounding the CMS and ATLAS experiments will be replaced with next-generation, high-performance superconducting magnets featuring larger apertures and higher magnetic fields than those currently used in the LHC. These magnets will be powered using a novel superconducting link and state-of-the-art power converters. Upgraded quench detection and protection systems will protect the magnet circuits. This work provides a comprehensive overview of the HL-LHC magnet circuits and their associated complexities. The commissioning methodology for the HL-LHC magnet circuits is outlined, detailing its validation within the HL-LHC Inner Triplet String test facility, currently under construction, prior to deployment within the CERN accelerator complex. These procedures ensure the reliability and operational readiness of the upgraded systems, paving the way for a successful magnet circuits operation in the HL-LHC era.
Paper: WEPB035
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB035
About: Received: 28 May 2025 — Revised: 31 May 2025 — Accepted: 31 May 2025 — Issue date: 06 Jun 2025
WEPB036
Nanometer sensitive vibration measurement system R&D status for SuperKEKB final focus
1772
SuperKEKB, a double ring circular collider with 7 GeV electron and 4 GeV positron beams, utilizes “nano-beam collision scheme” in which low emittance beams collide at large crossing angle. Positional fluctuations of the colliding beams are predicted to have a deleterious impact on luminosity; therefore, it is important to measure position oscillation of its superconducting quadrupole Final Focus (FF) magnets. KEK has developed, in collaboration with Brookhaven National Lab, a stabilized pickup-coil system to measure the magnetic field center oscillations of FF quadrupoles. This system is currently undergoing checkout and calibration at KEK using a permanent magnet quadrupole as a FF stand-in. In this paper, we will report on the measurement system status and our calibration results. This work is relevant for any high-luminosity collider that uses few-nanometer sized beams such as the proposed future ILC and FCC-ee Higgs Factories.
Paper: WEPB036
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB036
About: Received: 27 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
WEPB037
Faint magnetic field shield using the Meissner effect
1775
Magnetic fields play an important role in many physics studies, and many measurement items in physics experiments require control of micro magnetic fields. Although superconducting accelerating cavities can generate high electric fields at low power, the material niobium is a type-II superconductor, and trapping the ambient magnetic flux during the superconducting transition increases the operational losses. For this reason, micro magnetic shielding is important, and strengthening micro magnetic shielding is essential when aiming for further power saving. Therefore, we have begun to study the shielding effect of micro magnetic fields based on the Meissner effect of superconductors, which are perfectly antimagnetic. We have selected AMR (Anisotropic-Magneto-Resistive) type 3-axis sensors, drive five 3-axis sensors under cryogenic temperature, and bring their signals to the room temperature side with nine cables, including the power supply, by multiplexing. The signals were calibrated with the output of the FluxGate under cryogenic conditions. Preliminary results show that the amount of flux rejection is generally monotonically increasing with temperature gradient.
Paper: WEPB037
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB037
About: Received: 02 Jun 2025 — Revised: 03 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
WEPB038
Magnetic circuit design and consideration for HTSW using 12mm HTS tape
1779
The National Synchrotron Radiation Research Center (NSRRC) is focused on the application of 2G high-temperature superconducting tape (2G-HTS) for the insertion device in the Taiwan Photon Source (TPS) synchrotron ring. A preliminary design for a 2G-HTS wiggler (HTSW) is being developed, with considerations for sharing the SRF straight-section to make efficient use of space. The target field strength of the HTSW is 3.5 T, chosen to avoid increasing electron beam emittance. The HTSW is also designed to operate using a cryogen-free cryostat with a cryocooler to reduce liquid helium consumption. Safety margins for the current density applied to the HTS tape have been considered to prevent quenching during operation. Various parameters of the HTSW have been optimized and discussed to meet operational requirements, and a set of suitable parameters for HTSW in TPS is presented in this letter.
Paper: WEPB038
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB038
About: Received: 16 May 2025 — Revised: 29 May 2025 — Accepted: 31 May 2025 — Issue date: 06 Jun 2025
R&D of 2G-HTS wiggler operated in the cryogen-free system
The National Synchrotron Radiation Research Center (NSRRC) has been at the forefront of advancing synchrotron radiation technologies, including the development of advanced magnet systems. We integrated a wiggler magnet utilizing 2G High Temperature Superconductor (HTS) tape into a cryogen-free system. The wiggler, an essential component for enhancing radiation output, operates effectively within a cryogen-free environment, enabling operational stability and efficiency. The use of 2G-HTS tape significantly improves the magnet's performance, providing a high field strength while reducing thermal load and cryogenic requirements.
Preliminary study of a cryogen-free cryostat for a low-temperature superconducting magnet
This report details the mechanism design and heat load budget for a cryostat that replace liquid helium and liquid nitrogen with commercially available cold heads (cryocoolers). However, to ensure the proper functioning of cryogenic superconducting magnets with the limited cooling capacity of cryocoolers, careful management of heat transfer, insulation, cooling, electrical power, and vacuum components is essential. This paper provides an in-depth analysis of the thermal loads of a prototype superconducting wiggler magnet within a three-layer cavity, suspension system, current system, and electron beam chamber, utilizing two cryocoolers.
WEPB042
Third order resonance correction using new Trim-S system in J-PARC MR
1783
In the Japan Proton Accelerator Research Complex (J-PARC) Main Ring (MR), to address the issue of resonance correction for third-order resonances in both on- and off-momentum particles, an upgrade project utilizing 24 Trim-S units has been proposed based on numerical simulations. As a first step in verifying its effectiveness, four additional Trim-S (new Trim-S) power supplies, configured with a System-on-Chip (SoC) Field Programmable Gate Array (FPGA) controller, have been installed. The performance of the new system was experimentally verified by correcting the resonance using these 4 new Trim-S units. Beam loss was successfully reduced compared to that with the original Trim-S system, demonstrating the effectiveness of the new system.
Paper: WEPB042
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB042
About: Received: 14 Apr 2025 — Revised: 31 May 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
WEPB043
A study on the pattern waveform high-voltage power supply for the rapid cycling induction synchrotron
1787
The application of a 10 Hz repetitive induction synchrotron (IS) to the next generation of heavy ion therapy drivers is under investigation* **. The IS is characterized by the use of a pulse voltage to accelerate the beam, but until now, due to technical limitations, the magnitude of the pulse voltage could not be perfectly matched to the acceleration conditions. Instead, a pulse density modulation method has been adopted. However, this method inevitably induces synchro-beta coupling, which increases beam emittance. To overcome this problem, we develop a pattern-voltage dc power supply in which the output voltage waveform has a sinusoidal half-wave shape that matches the acceleration conditions. First, a mini-model was fabricated, and comparative experiments were conducted with three different circuit schemes: (A) a bipolar-controlled full-bridge circuit, (B) a unipolar-controlled full-bridge circuit, and (C) a series connected half-bridge circuit. This paper describes the results of these tests and issues for future study.
Paper: WEPB043
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB043
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
WEPB044
Development of a modular corrector magnet power supply with N+1 redundancy for TPS facilities
1790
This study presents a multi-module parallel current output system based on the correction magnet power supplies (CMPS) of the TPS storage ring. An N+1 re-dundant control interface card was designed to enable high-current, bipolar modular parallel output. The system integrates external DCCTs and current feed-back signals from the internal module. After PI com-pensation, these feedback signals are compared with the reference current to compute correction values distributed to each CMPS for closed-loop current con-trol. Each CMPS module provides an output of ±48 V/±10 A, and up to eight modules can be connected in parallel for a maximum output of ±80 A. Experimental results demonstrate long-term output current stability within 0.6 mA (or 7.5 ppm), with current noise spectra primarily below 500 µA. The system also supports N+1 redundancy and bipolar current output, offering a stable and flexible solution for magnet power control.
Paper: WEPB044
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB044
About: Received: 20 May 2025 — Revised: 31 May 2025 — Accepted: 01 Jun 2025 — Issue date: 06 Jun 2025
WEPB045
Performance Analysis and Stability Enhancement Plan for the Sextupole Magnet Power Supply in Storage Ring
1793
Since its official operation in 2016, the Taiwan Photon Source (TPS) has been dedicated to providing a stable and high-quality synchrotron radiation light source. The TPS storage ring is divided into 24 sections, each equipped with 7 sextupole power supply units, totaling 168 units. These power supplies are responsible for delivering precise and stable current to drive the sextupole magnets. This paper focuses on evaluating the long-term operational stability of the sextupole power supply system since its commissioning and proposes a targeted upgrade strategy to address potential reliability issues. To enhance overall system stability and yield, and to effectively reduce the frequency of beam trips caused by power supply faults, an upgrade plan involving the adoption of ultra-high-precision power supplies has been proposed. In addition, the removed high-precision power supplies will be repurposed as spares to improve system redundancy and fault response capability. The upgrade project is scheduled for full implementation by 2028. A pilot installation has already been completed in Cell 22, and successful electron beam storage was achieved at the end of 2024. Preliminary assessments suggest that, upon completion, the upgrade will reduce the number of beam trip events by approximately 2 to 3 times per year and decrease the total annual downtime by around 4 to 6 hours, thereby significantly improving the operational reliability of the TPS storage ring and the quality of service provided to users.
Paper: WEPB045
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB045
About: Received: 22 Apr 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
WEPB047
Insertion devices for the ultralow emittance storage ring ALBA II
1796
The ALBA synchrotron light source is undergoing a transformative upgrade to become a state-of-the-art fourth-generation facility, known as ALBA II. This upgrade will reduce the electron beam emittance to approximately 200 pm·rad, achieving a twentyfold improvement over the current performance. A key goal of the project is to maintain the existing source points for the insertion device beamlines; in fact, most of the currently installed devices will be kept after the upgrade. Nevertheless, selected insertion devices will be replaced to fully exploit the enhanced capabilities of the upgraded electron beam. Additionally, two available straight sections will be utilized to support the development of ultra-long beamlines exceeding 250 meters, enabling advanced nano-probing and coherence-based experimental techniques. This paper outlines the strategic plans for the new insertion devices, detailing the design criteria and the constraints guiding their development.
Paper: WEPB047
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB047
About: Received: 27 May 2025 — Revised: 30 May 2025 — Accepted: 31 May 2025 — Issue date: 06 Jun 2025
WEPB048
Magnetic measurement of a decommissioned insertion device at the Canadian Light Source
1800
The Canadian Light Source has decommissioned three insertion devices in recent years, replacing each with upgraded devices. The decommissioned devices are planar undulators that have seen approximately 15 years of operation in a 2.9 GeV storage ring, two being out-of-vacuum devices with 45 mm and 185 mm periods and one being an in-vacuum 20 mm device. In this paper we present magnetic measurements of the decommissioned 185 mm device (U185) with comparisons against the original measurements from before it was put into service.
Paper: WEPB048
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB048
About: Received: 24 May 2025 — Revised: 30 May 2025 — Accepted: 31 May 2025 — Issue date: 06 Jun 2025
WEPB049
Upgrade of the insertion device measurement benches and associated software at the ESRF
1804
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-IPAC25-WEPB049
About: Received: 26 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
WEPB050
Test coil-unit fabrication of Nb3Sn superconducting multipole wiggler for next generation light source in KEK-PF
1808
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-IPAC25-WEPB050
About: Received: 25 May 2025 — Revised: 31 May 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
A positron beamline for channeling experiments at MAMI
The Institute for Nuclear Physics of the University of Mainz operates the accelerator complex MAMI. Outstanding qualities are the continuous beam with an excellent beam quality, a very low energy spread, as well as its extremely high reliability. All kinds of channeling experiments require such a high quality beam with a low divergence. Positrons, however, are more preferable because they have a significant longer de-channeling length. The aim the project is the preparation of high-quality positron beam using the features of the MAMI accelerator. Positrons will be created by pair conversion of bremsstrahlung, produced by a focused 855 MeV electron beam of MAMI in a 10 um thick tungsten converter target, and energy selected by an outside open electron beam-line bending magnet. A sector magnet bends back the beam. Magnetic focusing elements in between are designed to prepare in a well shielded chamber about 6 m away from the converter target a low divergence positron beam. The features of the positron beam line such as the positron rate, the beam spot size and the divergence of the positron beam will be discussed. First channeling experiments with Silicon crystals will be presented.
WEPB052
The impact of insertion devices on Solaris storage ring optics
1812
This study investigates the influence of insertion devices (IDs) on the optical properties of the Solaris electron storage ring through a combination of experimental measurements and simulations. The effects of various ID settings were analyzed using tune measurements and the Linear Optics from Closed Orbits (LOCO) method. These results were compared with simulations performed using the Python Accelerator Toolbox (pyAT). Furthermore, a Long Short-Term Memory (LSTM) neural network was developed and tested for forecasting corrector magnet currents associated with the IDs. Diagnostics included monitoring the electron beam in the storage ring and photons delivered to beamlines. Additionally, the performance of both slow and fast orbit correction systems in response to ID-induced perturbations was assessed. This work provides insights into ID impact on beam dynamics and highlights the potential of machine learning for predictive control in accelerator systems.
Paper: WEPB052
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB052
About: Received: 26 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
Status of elliptically polarized undulator at NSRRC
Since the completion of Taiwan Photon Source (TPS) commissioning in 2015, we have developed and constructed nine APPLE-II undulators of various designs to provide users with soft X-ray sources, particularly for circularly polarized light. To optimize the use of straight-section space, the lengths of the APPLE undulators range from 4.4 to 0.8 meters to accommodate installation constraints. Additionally, an APPLE undulator capable of tapering up to 2 mrad has been developed to meet the spectral demands of broad bandwidth. In pursuit of EPU designs suitable for operation in low-emittance accelerators, we have initiated studies on closed-gap EPUs and constructed as well as experimentally validated a novel insertion device, known as the THU, capable of delivering strong circularly polarized magnetic fields. Moreover, we are also developing a closed-gap type undulator combining electromagnets with permanent magnet structures to generate time-varying magnetic fields, enabling rapid switching of circularly polarized light.
WEPB054
Advanced power density mapping for FEA simulations of synchrotron accelerator high heat load components
1815
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-IPAC25-WEPB054
About: Received: 07 May 2025 — Revised: 30 May 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
WEPB055
Design and development a measurement system for magnetic tuning of undulator magnets
1818
The permanent-magnet in-vacuum undulator technique is critical for the Taiwan Photon Source(TPS) at the National Synchrotron Radiation Research Center(NSRRC). Before installing the magnet arrays in the vacuum chamber, the phase error of the undulator is optimized by adjusting the magnetic field. Optimizing phase errors is a complex and time-consuming task. The conventional measurement method involves using Hall probes to measure the magnetic field and a stretched-wire(SW) to measure the integral field of the undulator. In this work, we propose a method for tune the local magnetic field by utilizing the correlation between the gap and the magnetic field. We have demonstrated that using gap sensors allows us to more effectively determine whether to tune the magnetic field of the upper or lower magnet array. Additionally, we have demonstrated for the first time the use of the pulsed wire measurement (PWM) method for magnetic sorting.
Paper: WEPB055
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB055
About: Received: 14 May 2025 — Revised: 01 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
WEPB056
Status of VPU development for PAL-XFEL
1822
PAL-XFEL is planning to install second hard X-ray undulator line (HX2) to meet the high beamtime demand from the users. The photon energy range for the second hard X-ray beam line is from 2~ to 11 keV which is lower than the first hard X-ray photon energy range (2 ~ 20 keV). The required undulator parameters are 35 mm period, max Keff=3.48 at 9.00 mm gap, ~ 3.0 m magnetic length with phase error less than 5 degrees. In addition to the existing conventional undulator design, horizontal gap vertical polarized undulator (HGVPU) concept is also being considered. HGVPU is well developed by LCLS-II team and applied in LCLS-II. In this report, we summarize the VPU design for PAL-XFEL HX2, and reports progress in the prototyping.
Paper: WEPB056
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB056
About: Received: 29 May 2025 — Revised: 30 May 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
WEPB057
Field measurements of a short period helical superconducting undulator
1825
Superconducting undulators (SCUs) may be capable of generating stronger magnetic fields at shorter periods than can be achieved using permanent magnet undulators. Therefore, the range of x-ray wavelengths that an XFEL facility can generate for users could be expanded by exploiting SCU technology. Prototyping work is ongoing at STFC to build a helical superconducting undulator (HSCU) with 13 mm period and 5 mm magnetic gap designed for future XFEL facilities. As part of this work, a test cryostat has been built to cool 325 mm long prototype magnets to 4 K and to measure the field profile of the HSCU using a cryogenic Hall sensor. The magnetic field measurements are necessary to confirm the peak-to-peak field quality and trajectory wander of an electron beam through the device. These quantities must be measured to understand the impact of the HSCU on the FEL radiation output. The trajectory wander can be minimised through the use of field integral corrector coils at either end of the HSCU coil. We present here a description of the test cryostat and the results of the magnetic field measurement regime performed on the prototype HSCU coil.
Paper: WEPB057
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB057
About: Received: 21 May 2025 — Revised: 06 Jun 2025 — Accepted: 06 Jun 2025 — Issue date: 06 Jun 2025
Radiation damage and refurbishment of undulator in SXFEL
Irradiation-induced damage to undulators has become a critical problem in the operation of synchrotron radiation facilities and free-electron laser facilities. During the commissioning and light output phases of the Shanghai Soft X-ray Free Electron Laser facility, the performance of the radiation deteriorated. The main reason for this problem is the impact of high-energy particles on the undulator magnets, which compromised the quality of the magnetic field. This paper examines the radiation damage sustained by the undulators and their refurbishment process.
WEPB059
Testing and characterization of surface treatment techniques for enhancing the HV performance of kickers
1829
Accelerator kicker magnets, which commonly use ferrite and other insulating materials, can encounter High Voltage (HV) performance limitations due to interactions with the particle beam. These interactions, can lead to electron cloud buildup and charging phenomena on exposed surfaces, negatively impacting kicker performance, particularly at high beam intensities. To mitigate these effects, surface treatment techniques are investigated to improve the HV kicker performance under such conditions. A dedicated set-up is under development to perform HV testing of treated surfaces in both ambient and in vacuum conditions, closely simulating operational conditions. This paper presents insights into the effects of these surface treatments on material properties, supporting strategies to enhance HV kicker reliability at higher beam intensities.
Paper: WEPB059
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB059
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
WEPB060
Stripline kicker design for FCC-ee booster injection and damping ring
1833
The FCC-ee booster injection kicker, will be injecting 4 particles bunches per single kick. The bunch separation in the booster ring is 25 ns and therefore requiring a faster kicker rise and fall time to not perturb injected or already circulating bunches. The wakefield impedance of the stripline is also important to not perturb the stored beam as well as it is necessary to ensure a good integrated fields and field homogeneity for kicking the bunches. The major challenge is to provide a precise impedance matching along the entire path of the electric pulse from the generator to the stripline termination. Transmission line cables, connectors and feedthroughs may already distort the pulse. 3D model of the stripline magnet including the high voltage connectors and simulation model of cables and generator was designed. It is shown that the results of the stripline magnet simulations meets the requirements, but the design of the entire system will need to be supplemented by research into active compensation for cable pulse distortion. The results are discussed in terms of validity due to assumed component parameters and ideas for benchmarking on a laboratory prototype are outlined.
Paper: WEPB060
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB060
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
WEPB061
High repetition tests of a pulsed power supply using SiC-MOSFETs for a fast kicker system in KEK-PF
1837
A pulsed power supply (PPS) using SiC-MOSFETs is an essential component in the camshaft-bunch system at KEK-PF *. The system requires the PPS to generate half-sine pulses with a peak current of 500 A, a pulse width of 200 ns, and a repetition rate (rep-rate) of 800 kHz. We have developed a prototype PPS consisting of a resonant circuit (RC) to generate half-sine pulses with a SiC-MOSFET switching module (SWM). The SWM, manufactured by NexFi Technology, has a rated voltage of 24 kV and a maximum rep-rate of 400 kHz. The main challenges in RC development were to reduce the charging time of the RC and power consumption during high-frequency operation. Additionally, film capacitors used in a previous prototype * required replacement because their permittivity had degraded during high-frequency operation. To overcome these challenges, we designed a RC with an energy recovery circuit, which reduced the charging time to 1 µs and power consumption by 90%. To ensure reliability, the film capacitors were replaced with vacuum capacitors. This report presents the prototype design, performance tests at a rep-rate of 400 kHz, and evaluation of long-term reliability at a rep-rate of 100 kHz.
Paper: WEPB061
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB061
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
WEPB062
Development of a compact high voltage pulse power supply of MARX-type for muon linac klystron
1841
We have been developing a compact pulse power supply with output pulse waveform specifications of 75kV/40A/50us/25Hz. This power supply is used to drive klystron for muon linac, which requires high stability and reliability. Next-generation power semiconductor SiC-MOSFETs with excellent characteristics of ultra-high breakdown voltage and low loss at 13kV, which were realized through the technological development of wide bandgap semiconductor devices, are used. Combining this SiC-MOSFET with the MARX circuit will realize a more compact pulse power supply with lower loss than conventional ones. In addition, it can be applied to portable accelerators in the future. In this presentation, the circuit design of the MARX power supply will be reported.
Paper: WEPB062
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB062
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
WEPB063
Study of a fast kicker magnet for beam scanning in VHEE therapy
1844
Over the past two decades, very high-energy electron (VHEE) beams ranging from 50 to 250 MeV have been explored as a potential technology for treating deep-seated tumors. FLASH radiation therapy (FLASH-RT) delivers ultra-high dose rates (UHDR) within a few milliseconds, suggests the possibility of enhanced cancer cell lethality while reducing damage to normal tissues. Combining VHEE with FLASH-RT shows potential in cancer treatment. Pencil beam scanning (PBS) is an important technique in VHEE radiotherapy. However, the ultra-short treatment times required by FLASH-RT (0.1–1 second) imply that the scanning speed must be very high, necessitating linear accelerators (LINACs) with a repetition rate significantly higher than 1 kHz, which is challenging to achieve. A fast kicker magnet, consisting of a one-turn coil and a pulsed power supply, can generate a magnetic field with rapid rise and fall times. A LINAC can produce an electron beam with a variable bunch train of 0.1-1 μs. By deflecting the bunch train using a fast kicker magnet, it is possible to generate a line scan that approximates the functionality of pencil beam scanning.
Paper: WEPB063
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB063
About: Received: 07 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
WEPB064
Development of a 13 kV SiC-MOSFET-based pulsed power supply for evaluating metallic materials under high electric fields
1847
To perform high electric field experiments for evaluating the vacuum breakdown characteristics of accelerator materials, we have developed a high-voltage pulsed power supply capable of providing a 10 kV peak voltage, 1 µs pulse width, and 1 kHz repetition rate. This system is designed to reliably apply intense fields to metallic electrodes with load capacitances up to 650 pF. To ensure operational reliability and prevent potential equipment damage, it incorporates an interlock system that halts operation when load short-circuits or external interlock signals are detected. By employing a 13 kV SiC-MOSFET developed under the Tsukuba Power Electronics Constellation (TPEC), we reduced the number of components and improved overall reliability. This report presents the technical features and performance of the power supply, demonstrating that it meets the operational specifications necessary for evaluating candidate materials under high electric field conditions.
Paper: WEPB064
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB064
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
WEPB065
Development of compact ultra-high power pulsed power supply
1850
Currently, pulsed power supply systems with output power of several GW, output voltage of several hundred kV, and pulse width of 100 ns are difficult to miniaturize and portability is a limitation for industrial applications. We are developing a pulsed power supply with an output power of 4 GW, an output voltage of 200 kV, and a pulse width of 100 ns, which is 1/20th the mass of conventional products, in order to solve this limitation. In this presentation, we will give an overview of the system design and the current status of the development.
Paper: WEPB065
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB065
About: Received: 27 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
Status of PIP-II HB650 cavities production
STFC is responsible for delivering 20 high-beta 650 MHz cavities for the PIP-II project, with industry partners now producing series cavities. Both pre-series cavities have set world records in performance and cleanliness, meeting the project’s stringent requirement for field emission-free operation, accelerating gradient, and Quality factor. Achieving this milestone required an industrialization of advanced processing techniques, including cold electropolishing and nitrogen doping, and a major effort to optimize cleanroom operations at the vendor’s facility. We will present the journey from prototyping to industrial production, highlighting the technology transfer, cleanroom upgrades, and QA/QC procedures that enabled these record-breaking results. Early performance data from the first series cavities will also be shared, demonstrating progress toward full-scale production.
WEPB067
High-power, high-repetition-rate X-band power source at X-LAB, the X-band laboratory for accelerators and beams at the University of Melbourne
1853
The X-LAB has been commissioned at the University of Melbourne. A key project within this laboratory involves rehoming half of the CERN high-gradient X-band test stand, XBOX3, now known as Mel-BOX. This initiative aims to validate the performance of high-gradient traveling wave accelerating structures operating at a frequency of 12 GHz. Mel-BOX is employed to evaluate the performance of these accelerating structures under high-power pulsed RF conditions. Two TD24 high-gradient structures, previously conditioned at CERN, were reconditioned at X-LAB after being shipped and stored for five years. Additional components have also been tested, including a compact pillbox-type RF window with traveling waves in ceramic, SLED-I type pulse compressors with a novel piston design, and high-power loads fabricated via 3D titanium printing and 1-meter-long stainless steel. As with XBOX3, Mel-BOX utilizes the combined power of two high-average-power klystron units to feed two test slots at a repetition rate of up to 400 Hz. Additionally, there are plans to leverage this technology as a foundation for developing compact accelerators for medical and university applications.
Paper: WEPB067
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB067
About: Received: 28 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
Optimization of deposition parameters of Nb3Sn thin film on copper with and without buffer layer
In this study, superconducting Nb3Sn films were synthesised on different substrate such as sapphire, diamond turned copper and polished Nb, by DC magnetron sputtering from a single stoichiometric alloy Nb3Sn target. The structural, morphological and superconducting properties of the films were investigated. The effect of different deposition and substrate was examined. The film properties are characterized by XRD, SEM, EDX, SIMS and XPS. The DC superconducting properties of the films deposited on sapphire are characterized by a four-point probe measurement and squid magnetometer down to cryogenic temperatures. The RF surface resistance and critical temperature of films deposited on copper was measured over a temperature range of 4–23 K using 8.7 GHz choke Nb cavity. As-deposited Nb3Sn films on sapphire had a superconducting critical temperature of 18.26 K for optimum deposition condition. For the films deposited on copper and niobium has Tc of 16.5 K to 17.5 K , the surface resistance for direct 2.5 µm thick Nb3Sn, on copper was 25μΩ, which increased by two orders of magnitude when deposited on buffer layer of 4 µm thick Nb.
Defects characterization of superconducting RF cavities via replica technology
The SHINE project requires more than six hundred of 1.3GHz cavities and sixteen 3.9GHz cavities for the superconducting accelerator. These cavities are from both domestic and foreign companies. Surface defects, such as cat-eyes, aluminum inclusions and scratches, are one of the most important factors strongly related to RF performance of cavities. The multiplicity of sizes, depths and locations of defects on cavities will bring different effects in RF test. Characterizing the precise data of 3D size and location of the defects is of great significance to study the corresponding relationship between the surface defects and RF performance. In this paper, we will report a technology of replicating and characterizing surface defects on the superconducting cavities in SHINE.
Development of a variable power divider for the ILC power distribution system
The R&D of the radio frequency (RF) power distribution system (PDS) for the International Linear Collider is ongoing. The PDS is designed to drive 39 superconducting RF (SRF) cavities by a 10 MW multibeam klystron. The key feature of the PDS is the usage of power dividers and phase shifters, which allow driving all cavities below their respective operational limits over the whole flattop. This is necessary to maximize the beam energy. Following the design of the variable power divider (VPD) developed at SLAC, we intend to combine power dividing and phase shifting capabilities in a single device. The VPD consists of two folded magic tees (FMTs), four small WR650 waveguides, and two U-bends. The U-bends serve as variable phase shifters. The FMTs have been designed, fabricated, and tested. A prototype for the checking the working mechanism of U-bend phase shifter was produced. Preparations for its high-power testing are currently underway.
Impact of ion and neutral angular distribution on thin film deposition in HiPIMS and bipolar HiPIMS
Unipolar and bipolar High Power Impulse Magnetron Sputtering (HiPIMS) are widely used techniques for depositing superconducting thin films, utilizing various magnetron configurations such as planar and cylindrical. In this study, ion energy and flux were measured from both planar and cylindrical magnetrons under varying pressure and power conditions, using mass spectrometry and Retarding Field Energy Analyzers (RFEA). To investigate the angular dependence of these configurations, diagnostics were performed over a full 180° sweep of the sputtered material. A Langmuir probe was employed to measure the current-voltage (I-V) characteristics of the plasma. The angular dependence of the deposition rate was evaluated using a charge-selective quartz crystal microbalance and compared across the different magnetron configurations. Superconducting Nb films were then deposited at various angular positions, with substrates either grounded or biased, and analyzed via X-ray Photoelectron Spectroscopy (XPS) and Scanning Electron Microscopy (SEM). The findings of this work provide insights into optimizing deposition rates and film growth, with potential in enhancing 1.3 GHz cavity coating.
Characterization and modeling of electropolishing for copper cavities in superconducting applications
To enhance the performance of superconducting radiofrequency (SRF) cavities, a promising solution involves depositing a superconducting material onto copper RF cavities. A prerequisite for this process is the electropolishing of the copper cavities. At Jefferson Lab (JLab), a modeling study of the electropolishing process for 1.3 GHz copper cavities was conducted. This paper focuses on two main aspects. First, the characterization of the electropolishing solution, consisting of H?PO? and n-butanol, was carried out through chemical and electrochemical analyses. This enabled the development of a comprehensive surface preparation process for the electropolishing of copper cavities, which involved defining all critical parameters such as voltage, temperature, and electrolyte flow.Second, these parameters were used as inputs for COMSOL simulations to optimize the electropolishing process. The simulations incorporated modules for secondary current density, heat transfer, and laminar flow to refine the cathode shape and enhance the process efficiency
WEPB075
ESS superconducting linac cold technical commissioning
1857
The European Spallation Source (ESS) superconducting linear accelerator (linac) represents a key component in delivering high-intensity proton beams for cutting-edge neutron science research. This paper details the first cold technical commissioning of the superconducting linac in 2MW configuration, focusing on the performance validation of cryomodules, superconducting radio-frequency (SRF) cavities and associated systems.
Paper: WEPB075
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB075
About: Received: 03 Jun 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
WEPB076
RF design for optimal high-gradient performance of a four-quadrant structure for the ASTERIX project
1861
The ASTERIX project, funded by CSN5 and proposed at INFN-LNF, aims to demonstrate a practical, meter-long X-band RF structure for linear accelerators made of hard copper and divided into four quadrants. The prototypes will be constructed by TIG welding. In the first year of the feasibility study, we will design the RF cavities for two full structures working at single-bunch and multi-bunch operation. In this paper, structures operating at single-bunch mode for ASTERIX are numerically studied. The surface field enhancements of the quadrant-type accelerating structures are the most challenging issue to be resolved. The geometry near the gap between four quadrants is carefully optimized and obtain low surface field while maintaining high RF performance.
Paper: WEPB076
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB076
About: Received: 28 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
WEPB077
Performance on high-power test bench of RF couplers for the LIPAc’s RFQ
1864
The Linear IFMIF Prototype Accelerator (LIPAc) in Rokkasho, Japan, designed to accelerate p+ to 4.5 MeV and D+ to 9 MeV at 62.5 mA and 125 mA in Continuous Wave (CW) mode, respectively, is under commissioning and about to enter into its final stages. A high-power test bench was developed for the testing and conditioning of the Radio-Frequency (RF) couplers of the RF Quadrupole (RFQ) cavity. The processing, requiring thermomechanical validation up to 200 kW and CW, is currently ongoing. Several tests were done, during which multipacting and thermal outgassing was observed in numerous power bands, particularly at 70 - 90 kW for the couplers, which is crucial for RFQ conditioning at nominal voltage. Subsequent tests showed that the cavity and couplers performed as expected at forward power levels close to beam operation (~ 160 kW).
Paper: WEPB077
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB077
About: Received: 27 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
WEPB078
LIPAc RF system commissioning: busting one EMC problem at a time
1867
Addressing electromagnetic compatibility (EMC) issues at the design stage is important. However, for a prototype like the Linear IFMIF Prototype Accelerator (LIPAc) and its RadioFrequency (RF) system providing over 2 MW of RF power, problems during the commissioning have to be expected. Random interlocks and probability of occurrence increasing with the number RF modules, the power level or the duty cycle are often evidences of EMC problems, sometimes known as RF noise. Those conditions are difficult to reproduce by the manufacturers and if no margins are considered, they need to be addressed by a dedicated team onsite*. Two solved EMC problems will illustrate the basics of the mitigation strategy: locate and stop the RF noise at the source or protect the victims from the RF noise. The first approach is applied on the air cooling: the noise from an inverter, driving a motor over tens of meters of cables, affected multiple systems sharing the same cable tray and had to be fixed at its source. The second way is applied on the tetrodes high voltage input monitor, affected by RF leaking probably from the tetrode: a source difficult to stop that called for a protection of the victim.
Paper: WEPB078
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB078
About: Received: 26 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
Predicting LANSCE klystron health and performance
Beam production through the LANSCE accelerator is currently disrupted due to lack of critical klystrons spares that power the Side Coupled Cavity Linear accelerator (SCCL). The situation is so dire that the facility had to compromise running beam at 100MeV for 2024 run cycle instead of its nominal 800MeV. This project aims to predict the future performance of those critical klystron units through upgrading our current testing capabilities and developing a prediction model that can warn about klystron failures before they happen. This paper will cover improving current measurement, diagnostics, and controls, developing initial klystron health and performance prediction model and automating expert dependent klystron testing. This project will increase klystron reliability for the SCCL enabling LANSCE to provide reliable 800MeV proton beam for the upcoming run cycles.
Magnetron-driven superconducting linacs for UNF transmutation
We describe a program to develop 805 MHz magnetron power sources to enable a cost effective one GeV Linac that is capable of CW operation at greater than 50 MW beam power. Compared to the klystrons now used at the ORNL SNS, magnetrons have about a factor of ten lower capital cost ($1/W vs $10/W) and much higher wall power to beam power efficiency (almost 90% vs 50%). Two applications under consideration to ARPA-E are to use a spallation target driven by a high power proton Linac to produce copious neutrons to induce transmutations of all actinides in UNF for energy production or to destroy unwanted elements that have been extracted from stored UNF.
WEPB083
The cavity combiner development for TPS SSPA tower at NSRRC
1869
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-IPAC25-WEPB083
About: Received: 29 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 06 Jun 2025
WEPB084
Design of normal conducting quadrupoles for the spin rotator section in the EIC electron storage ring
1872
The interaction region IR6 in the Electron Storage Ring of the planned Electron Ion Collider facility at Brookhaven National Laboratory includes a section to rotate the electron spin into or out of the longitudinal direction. This section consists of superconducting solenoids, and normal conducting dipoles and quadrupoles. The geometry and field gradient requirements of the quadrupoles pose a challenge in their design with regards to yoke saturation and thereby field quality. Electromagnetic design of one such quadrupole is the focus of discussion in this article. The design process involves optimization of the pole tip, yoke and conductor size using two and three-dimensional finite element method tools.
Paper: WEPB084
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB084
About: Received: 22 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
WEPB085
Design and development of an extraction septum for the MYRRHA 100 MeV proton target facility
1875
SCK CEN is developing MYRRHA, a large-scale Accelerator Driven System. MYRRHA shall be a subcritical nuclear reactor driven by a high-power linear proton accelerator, which sustains the nuclear reaction. In the initial phase, known as the MINERVA project, the goal is to demonstrate the high reliability requirements on the accelerator. The two primary end users of the MINERVA project are the Full Power Facility and the Proton Target Facility. In collaboration with SCK CEN, CERN studied and designed an extraction septum for the 100 MeV Proton Target Facility. Two distinct topologies have been evaluated magnetically and tracked particle simulations have been executed to validate the designs. A preferred low-power solution has been retained for a subsequent detailed design. A final magnetic verification to confirm the mechanical design requirements has been carried out. This has allowed to develop a detailed 3D mechanical design including all manufacturing tolerances required for subcontracting the magnet fabrication to the industry. This article covers the 2- and 3-dimensional magnetic modelling, the tracked particle simulations and the mechanical design of the septum magnet.
Paper: WEPB085
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB085
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
WEPB086
Design of prototype magnets for FETS-FFA
1878
Fixed Field Alternating gradient accelerators (FFA) hold promise for pulsed high intensity applications. No such FFA has been constructed to date; therefore a prototype - the Front End Test Stand-FFA (FETS-FFA) has been pro- posed to explore the feasibility of using FFA technology for the next generation spallation neutron source, ISIS-II. A key component of this prototype is its main magnets, which must meet several critical requirements: maintaining zero chro- maticity during acceleration, offering tune point flexibility, and providing a large dynamic aperture. The selected lattice incorporates a doublet spiral magnet design for more flexi- ble operations in the tune space. The magnetic field profile is generated by distributed conductors wound over the pole face; a 3D analysis using OPERA software was conducted to evaluate the settings necessary to produce the desired field. The cell tune variation was found to be within ±0.0015 hor- izontally and ±0.002 vertically, for four different working tune points.
Paper: WEPB086
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB086
About: Received: 28 May 2025 — Revised: 30 May 2025 — Accepted: 31 May 2025 — Issue date: 06 Jun 2025
WEPB087
Design of FFA magnet for the laser-hybrid accelerator for radiobiological applications (LhARA)
1882
LhARA, which stands for “Laser-hybrid Accelerator for Radiobiological Applications”, is a novel and flexible facil- ity dedicated to research in radiobiology. A proton beam of energy up to 15 MeV can be produced by a laser driven source, the beam then enters a Fixed Field Alternating (FFA) gradient accelerator for acceleration to produce a variable ex- traction energy between 15-127 MeV. To avoid uncontrolled beam loss, the operational tune was picked carefully to avoid resonances. The magnetic field must be adjusted to ensure that the tune stays at the same working point for different energy ranges. The FFA ring uses combined-function spiral magnets, which create a radial magnetic gradient through distributed conductors wrapped around the pole, each car- rying a different current. A three-dimensional study was carried out in OPERA 3D and the parameters of the magnet were optimized. The results showed that resonances up to fourth order were avoided for the entire range of acceleration for different operational energies entire range of acceleration and different operational energies.
Paper: WEPB087
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB087
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
Permanent magnet version of longitudinal gradient bending magnet for Korea-4GSR Project
A 4th generation storage ring based light source is being developed in Korea since 2021. It features <60 pm rad intrinsic beam emittance, about 800 m circumference, 4 GeV e-beam energy, full energy booster injection, and more than 40 beamlines which includes more than 24 insertion device (ID) beamlines. To optimize the beam emittances, longitudinal gradient bending magnet is applied in the storage ring design. The initial design was using conventional electrical excitation, but the design is changed to use permanent magnet (Sm2Co17) to minimize energy costs. In this report, the physics design and prototyping is described including field integral, field tuning, and temperature compensation scheme.
Development of moving long coil magnetic measurement system based on HALF magnets
Hefei Advanced Light Facility (HALF) consists of two main components: the injector and the storage ring, the core of the facility includes nearly one thousand magnets, of which there are more than one hundred conventional dipole magnets and longitudinal gradient bend magnets.The longitudinal integral field and its uniformity of these dipole magnets are typically measured by the Hall probe measurement system, which takes a long time to measure, and the measurement accuracy of the uniformity repeatability of the integral field can only reach 0.01%. The accuracy of the integral field uniformity of the long coil magnetic measurement system can reach less than 0.01%, and the measurement accuracy of the uniformity repeatability of the integral field can reach less than 0.005%. Therefore, to efficiently and accurately measure the uniformity of the integral field, there is a necessity to develop the moving long coil magnetic measurement system. This paper develops a moving long coil magnetic measurement system based on the technical requirements for the measurement of the integral field of dipole magnets in the HALF project.
The Canted Cosine Theta HTS sextupole demonstrator of FCC-ee
A single-aperture two-layer Canted-Cosine-Theta (CCT) sextupole magnet using as conductor high-temperature superconducting (HTS) ReBCO tape has been developed for the short straight sections (SSS) of the FCC-ee study. Manufacturing details, including paraffin wax impregnation and cryogenic temperature measurements, are presented. This demonstrator represents the first CCT magnet constructed from HTS tape.
Cryogenic cooling of superconducting devices
Superconducting magnets, RF cavities, undulators and wigglers are widely employed for particle accelerators and cooled under the cryogenic condition below 100 K. This paper describes the cryogenic cooling schemes of superconducting devices and the sources of the cooling power capacities: refrigerators, cryoplants, and cryocoolers. Their main features, such as temperature, pressure, and cooling powers will be presented, which facilitate R&D of superconducting devices.
MagCCT - magnetic field calculation and analysis code for CCT magnet
In order to develop a lightweight gantry for proton therapy, the canted–cosine–theta (CCT) superconducting magnet was considered to apply in the gantry development. The code MagCCT intended for magnetic field calculation and analysis for CCT magnet is described. The main features of the MagCCT are that it can calculate the magnetic fields of 3 different magnets: curved CCT, straight CCT and solenoid, analyzing harmonic field, and an easy-to-operate GUI interface. The usage of matrix operation ideas and parallel computing is a key issue in the MagCCT development. Comparison of magnetic field calculation results from MagCCT and those from TOSCA was presented.
WEPB099
Advancements in LINAC performance for enhanced stability and control: Integration of the Libera LLRF systems into the ScandiNova modulators
1886
For years, Instrumentation Technologies and ScandiNova have developed advanced products to optimize RF performances in LINAC applications. In 2024, the companies began integrating the Libera LLRF system into ScandiNova modulators during assembly. This innovation enables the modulators to offer enhanced operational flexibility and improved performances. This paper will focus on mechanical integration and performance results. The integrated system enables real-time monitoring of critical signals such as drive power to the RF amplifier and klystron, as well as forward and reflected klystron power. Performance metrics include amplitude stability <0.01% RMS and phase stability <0.01° RMS. Experimental results are presented using a ScandiNova modulator with an Sband klystron and a standard Sband Libera LLRF. Pulse-to-pulse stability measurements demonstrate consistency between conventional electrical methods and RF-based methods, achieving stability in the 10 ppm range. Electromagnetic compatibility tests confirm that the modulators do not interfere with the LLRF system. Additionally, new tools are introduced to identify components with the greatest impact on phase stability.
Paper: WEPB099
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB099
About: Received: 24 May 2025 — Revised: 30 May 2025 — Accepted: 31 May 2025 — Issue date: 06 Jun 2025
WEPB100
Development of ultra high power compact X-band pulse compressor
1890
We have developed a new SLED-type RF pulse compressor for powering ultra-high gradient X-band photoinjectors with pulse lengths shorter than 10 ns. Klystrons capable of generating these short pulses at multi-MW levels are non-existent. However, RF pulse compression is an alternative technique used to increase klystron output peak power at the cost of pulse length. Over the years, we have developed numerous pulse compression systems, including super-compact SLEDs for X-band transverse deflectors at SLAC’s LCLS and LCLS-II. Our new compact pulse compressor uses spherical cavities with axially-symmetric TE modes which have no electric field on the cavity surface. This allows our new SLED to potentially achieve higher peak RF power compared to the LCLS-II SLEDs. We present the design of this SLED composed of two spherical cavities and a waveguide hybrid with TE01 circular waveguide ports. During high power test this SLED produced peak RF power up to 317 MW.
Paper: WEPB100
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB100
About: Received: 28 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 06 Jun 2025
Design of high frequency pulse power supply for electron gun
The grid control power supply of the electron gun of the free electron laser (FEL) is a high frequency pulse power supply (HF-PPS), which has a special time structure. The macro pulse repetition frequency of the HF-PPS designed in this paper is 10 Hz, and the micro pulse repetition frequency is 476 MHz.
Upgrade of the kicker pulser based on LC resonanr circuit
LC resonant circuit is widely used in all kinds of pulse power supply because of its simple structure and reliable performance. Among them, the scheme with thyratron as the main power device has been verified for a long time in the BEPCII injection system. With the continuous improvement of the technical requirements of all kinds of accelerators, the performance of the pulser has become critical. In order to obtain the pulse signal with higher voltage and shorter bottom width, it is necessary to upgrade the equipment. This paper aims to introduce a new type of the pulser topology to meet the needs of the injection and extraction system for BEPCII-U and HEPS.
A half-sine type Marx generator designed for HEPS pre-kicker
HEPS is a nearly finished fourth-generation photon source with a 6 GeV energy storage ring. When machine protection is activated in the storage ring, the low beam emittance causes most particles to deposit nearly vertically on the collimator. This can result in concentrated heating, potentially leading to material melting of the collimator. Thereby, two pre-kickers are used to generate 4.52 µs half-sine magnetic fields in both horizontal and vertical directions upon receiving the protection signal, dispersing the particles throughout the entire ring to safeguard the collimator. However, during engineering construction, the circuit may have a total inductance that far exceeds the initial design, leading to inadequate voltage output from the prepared HV charging power supply. Comparing the Marx generator and the inductive adder voltage boosting topologies, the Marx generator offers a more compact and simpler design for long pulse applications. Therefore, this paper presents the design and testing of a two-stage Marx generator based on LC resonance to deliver a half-sine pulse to the pre-kicker.
WEPB107
A technique to improve the energy leakage of TM020-mode cavity for Super Tau Charm Facility
1894
TM020-mode cavity with a higher quality factor and a lower R/Q as compared to TM010 cavity is an attractive candidate for RF system of Super Tau-Charm Facility. However, the symmetrical electromagnetic field distribution at radial nodes is diluted by the introduction of a high-power input port and cavity frequency tuners. This results in the leakage of the accelerating mode and a weak damping of harmful modes. In order to address these issues, this paper proposes elliptic coaxial slots and tuning bumps on the inner wall to optimize the performance of the accelerating mode and harmful modes. Simulation results demonstrate that the energy leakage of the accelerating mode can be reduced below 1% during operation and all of harmful modes can be strongly damped.
Paper: WEPB107
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB107
About: Received: 27 May 2025 — Revised: 31 May 2025 — Accepted: 03 Jun 2025 — Issue date: 06 Jun 2025
WEPB108
A TM020-mode cavity with choke geometry for Super Tau-Charm Facility
1897
To meet the requirements of collider rings of Super Tau-Charm Facility (STCF) with a beam current of up to 2 A, a TM020-mode cavity with improved performance is designed in this paper. In order to address the issues of leakage of accelerating mode into the slots which has dampers inside, a choke geometry is introduced for this cavity. Through optimizations on this choke, the accelerating mode is fully reflected back into the cavity and all of harmful modes can be heavily suppressed. In addition, the nose shape and frequency tuner are also optimized in detail.
Paper: WEPB108
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB108
About: Received: 03 Jun 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 06 Jun 2025
WEPB113
Design of an online adjustable waveguide coupler for the TM020-mode cavity of proposed STCF
1901
The Super Tau-Charm Facility (STCF) project plans to use 12-15 TM020-mode cavities for each collider ring to compensate for the beam energy loss. Each cavity is designed to provide a voltage of 0.5 MV and a power of 250 kW for the beam. Therefore, an online adjustable waveguide coupler with a power capacity of CW 300 kW has to be developed for each cavity. This input coupler has a waveguide size the same as the half-height WR1500. The coupling between the cavity and the half-height WR1500 is realized by a rectangle hole with blending. This paper presents the electromagnetic design, the multipacting simulation, and the thermal and stress analysis of the input coupler in detail.
Paper: WEPB113
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB113
About: Received: 27 May 2025 — Revised: 30 May 2025 — Accepted: 01 Jun 2025 — Issue date: 06 Jun 2025