electron
MOYD3
RF acceleration with short pulses: Breaking the high-gradient barrier
24
Achieving high-gradient acceleration is critical to enabling future linear colliders, free-electron lasers, and other compact accelerator applications. The Argonne Wakefield Accelerator (AWA) group has pioneered short-pulse structure wakefield acceleration technology, which has shown remarkable promise for surpassing the long-standing barrier of ~100 MV/m in X-band normal-conducting structures. Recent experiments have demonstrated the feasibility of this approach, with gradients exceeding 300 MV/m in a variety of X-band accelerating structures and an X-band photogun. Experimental results indicate that the empirical scaling law used to estimate the RF breakdown rate (BDR ~ E^30 * t^5) may be too conservative for RF pulse durations below 10 ns. Potential advanced accelerator designs based on short-pulse acceleration will also be presented, including a conceptual design for an ultra-compact XFEL.
Paper: MOYD3
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOYD3
About: Received: 27 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
MOZD1
ILC accelerator status
30
The international linear collider (ILC) is a Higgs Factory, where electron-positrons are accelerated by the linear accelerators using Superconducting RF (SRF) cavities to 125 GeV. In 2013, the GDE, an international organization of researchers, already compiled the TDR. It is currently being studied under the International Development Team (IDT). Especially, from 2023, the ILC Technology Network (ITN), specifically under the IDT, will work on the development through international cooperation. This presentation will show an overview of the ILC and the recent developments under the ITN. First, an overview about the latest proposed Higgs factories of more than 250 GeV energy will be given. Second, we introduce the ILC accelerator, including the design, key technologies, accelerator systems. Finally, an detailed ongoing key technology developments, such as SRF cavities, nanobeam, and sources, for ILC project over the next few years will also be presented. We believe that these accelerator developments are not only crucial for ILC development but also for the improvements of future accelerators and various industrial and medical applications.
Paper: MOZD1
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOZD1
About: Received: 27 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOZN2
Development for various applications at compact ERL as a high-power CW SRF linac in KEK
48
It is about “Development for Various Application at Compact ERL as a high-current CW SRF linac in KEK”. As an introduction, the author will talk about the merit of the superconducting RF (SRF) cavity and also talk about our applied research based on Compact ERL (cERL) in KEK, which uses the Nb superconducting cavity and can make energy recovery operation. The cERL's characteristic using the high-current beam has the variety of applications; industrial applications using high-intensity terahertz light and mid-infrared FEL (free-electron laser). In addition, the high current CW beam irradiation was conducted for basic research on domestic production of nuclear medicine, strengthening of asphalt, and the highly efficient production of nanocellulose from wood in cERL. After talking these applications of cERL, next we will talk about “Future plan for applied research using superconducting accelerators”. One is the EUV-FEL light source development for EUV-lithography and the other is the development of compact superconducting RF accelerator based on Nb3Sn for high-power beam irradiation.
Paper: MOZN2
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOZN2
About: Received: 28 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOCN3
Searches for RF breakdown precursors using Cherenkov light in optical fibers
65
RF breakdown studies are crucial for machines relying on high-gradient, normal-conducting RF accelerating cavities. Searches for breakdown precursors in high-gradient test-stand data have been conducted* and highlight the need for a new diagnostic with improved temporal response**. Emission of Cherenkov light in optical fibers has been identified as one such diagnostic***, which occurs when charge showers due to breakdown are incident on the fiber. Optical fibers have been used previously as distributed Beam Loss Monitors. At the X-Band Laboratory for Accelerators and Beams (X-LAB), we position optical fibers adjacent to X-band cavities being conditioned for the proposed Compact Linear Collider (CLIC). We assess sensitivity of fibers to charge emitted by field emission and breakdown events. Since breakdown precursors may occur at sub-microsecond timescales**, we survey photon detectors best suited to examining fiber response and identifying precursors. We compare fiber signals to dark current captured by upstream and downstream Faraday Cups. In search of precursory phenomena, pulse-by-pulse evolution of fiber signals is examined for field-emission activity prior to breakdown.
Paper: MOCN3
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOCN3
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
MOPB001
Beam dynamics studies and vacuum diagnostics in the Solaris storage ring
69
Since 2015, the National Synchrotron Radiation Center SOLARIS has operated a light source supporting eight experimental beamlines. Following vacuum chamber replacements and beamline upgrades, the total beam lifetime at 400 mA has reached 13 hours in decay mode operation. Regular lifetime measurements are conducted to monitor vacuum quality, residual gas composition, and potential stability issues arising from machine aging. Beam dynamics studies involve measuring electron beam lifetimes at 400 mA, 300 mA, and low currents (as low as 10 mA) under both multibunch and single-bunch operating modes. A particular focus is placed on intra-beam electron interactions influencing the Touschek lifetime and the effects of residual gas on beam scattering. These investigations provide valuable insights into vacuum performance, electron bunch behavior, and overall storage ring dynamics.
Paper: MOPB001
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB001
About: Received: 27 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPB002
An IGBT pulser for the nonlinear in-vacuum kicker at Taiwan Photon Source
72
A test unit pulser for the proposed NIK (nonlinear in-vacuum kicker) project at TPS (Taiwan Photon Source) was fabricated in order to provide uniform kick strength applying onto the injected bunch train. This newly built flattop pulser gives much improved drive current pulse shape in comparison with previously used half-sine pulser. This flattop pulser will result in high injection efficiency and provide adjustable capability in terms of bunch train filling pattern.
Paper: MOPB002
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB002
About: Received: 20 Apr 2025 — Revised: 14 Jun 2025 — Accepted: 14 Jun 2025 — Issue date: 10 Jul 2025
MOPB007
Echo-enabled harmonic generation at the DELTA storage ring
87
Echo-enabled harmonic generation (EEHG) has been proposed as a seeding method for free-electron lasers but can also be employed to generate ultrashort radiation pulses at electron storage rings. With a twofold laser-electron interaction in two undulators ("modulators"), each followed by a magnetic chicane, an electron phase space structure with high harmonic content is produced, which gives rise to coherent emission of radiation at short wavelengths. The duration of the coherently emitted pulses in a third undulator ("radiator") is given by the laser pulse durations. Thus, EEHG pulses can be three orders of magnitude shorter but still more intense than conventional synchrotron light pulses. The worldwide first storage ring implementation of EEHG was undertaken at the 1.5-GeV synchrotron light source DELTA at TU Dortmund University by reconfiguring an electromagnetic undulator. With a total length of only 4.75 m, the setup is very compact and fits in a single straight section. The paper presents technical aspects of the EEHG implementation as well as first results.
Paper: MOPB007
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB007
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPB014
Relativistic strophotron free electron laser
95
The scheme with quadrupole lenses is presented for realization relativistic strophotron type Free electron laser. Equations of motion are solved and trajectories are found. It is shown, that movement of electrons in presented scheme is stable in both transverse directions.
Paper: MOPB014
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB014
About: Received: 24 Apr 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPB015
Tapering enhanced superradiance - tapering rate optimization using analytical magnetic field maps
98
THz sources are typically very limited in power, making high-power sources scarce. One of the most promising THz sources are the Free Electron Lasers (FELs), which can generate high-power THz radiation using an undulator structure. Undulator radiation is an incoherent synchrotron spontaneous emission whose energy is proportional to the number of particles in the beam (𝑁). By longitudinally bunching the charged particle beam, a coherent spontaneous emission is generated and referred to as a super-radiant emission. Unlike spontaneous emission, super-radiant energy yield is proportional to N^2. However, like typical FELs, the energy conversion efficiency is rather low. Here, we demonstrate a novel THz source structure based on a radiative interaction scheme of super-radiance – Tapered Enhanced Super-radiance (TES), which employs a tapered (amplitude) undulator in the zero-slippage condition. This method yields a significantly more powerful and efficient THz radiation source. An optimization algorithm was developed to obtain a tapering rate that yields the most efficient energy conversion from the electron beam to the radiation field.
Paper: MOPB015
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB015
About: Received: 02 Jun 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPB019
Flash status 2024 - FEL operation for users and upgrade shutdown
102
FLASH, the XUV and soft X-ray free-electron laser at DESY, is currently undergoing the 2nd of two long upgrade shutdowns within the FLASH2020+ project. The 1st half of 2024 was dedicated to user operation. The upgrade shutdown started in June 2024, and we plan to come back to beam operation in August 2025. Here we will discuss the operational highlights of the first half of 2024, briefly describe the new features being implemented, and report on the shutdown status.
Paper: MOPB019
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB019
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPB021
Commissioning of the soft X-ray variable polarization afterburner at the European XFEL
106
Following the successful commissioning of the soft X-ray planar undulator system (SASE3), the European XFEL user community expressed a strong demand to extend the radiation properties and provide the possibility to obtain variable polarization modes. It was therefore decided to build a helical afterburner behind the SASE3 system in collaboration with Paul Scherrer Institute (PSI). The final installation of the undulators in the tunnel took place at the beginning of 2024. Since then, a series of measures have been taken to commission four APPLE-X undulators, which form the base for the helical afterburner. The main objective is to maximally suppress the linear polarization of planar undulators in order to obtain the purest radiation from helical undulators. The methods and results of the optimization to achieve a maximum contrast between the pulse intensity generated by planar and helical undulators as well as the operating experience are presented.
Paper: MOPB021
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB021
About: Received: 26 May 2025 — Revised: 01 Jun 2025 — Accepted: 01 Jun 2025 — Issue date: 10 Jul 2025
MOPB022
Design of beam transport system integrating active plasma lens for laser-plasma-driven EUV free-electron lasers
110
Laser-plasma accelerators (LPAs) produce high-quality electron beams with the GeV-level of the energy, the high peak currents and low emittance, making them ideal for compact novel free-electron lasers (FELs). However, the large angular divergence and energy spread of these beams pose challenges for efficient beam transport and overall FEL performance. This study explores the use of an active plasma lens (APL) as a capture block to improve the transport of LPA-generated beams into an undulator. Initial beam parameters were based on published results from LWFA studies. In this report, we present the results of the modeling conducted to design an efficient LPA-based electron beamline and optimize the FEL regime for the extreme ultraviolet (EUV) range. Our goal is to achieve saturation of the photon beam power within a single unit. The results show that the APL enables efficient beam transport and facilitates the generation of high-brightness coherent X-rays. This work underscores the potential of APLs in developing compact FELs and advancing LPA beams. This technology is essential for creating a new generation of FELs at ELI-ERIC in the Czech Republic and within the EuPRAXIA project.
Paper: MOPB022
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB022
About: Received: 27 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
MOPB023
Concept and preliminary design of the DALI accelerator lattice
114
The Dresden Advanced Light Infrastructure (DALI) project at Helmholtz-Zentrum Dresden-Rossendorf (HZDR) is a visionary initiative to establish a state-of-the-art light source facility, catering to cutting-edge research in materials science, biology, and other interdisciplinary fields. A cornerstone of this ambitious project is the development of an advanced accelerator lattice tailored to meet the unique demands of high-intensity, ultra-bright photon production. This presentation introduces the conceptual framework and preliminary design of the DALI accelerator lattice. Key features include a modular design optimized for stability, flexibility, and scalability, ensuring compatibility with diverse experimental setups. The lattice must integrate advanced beam dynamics solutions to achieve precise control over beam quality, energy spread, and emittance, crucial for generating high-brightness radiation. Early design studies highlight the potential of DALI to set new benchmarks in light source performance. This presentation seeks to engage the accelerator community in refining the lattice design and exploring its applications in cutting-edge research.
Paper: MOPB023
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB023
About: Received: 23 May 2025 — Revised: 31 May 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
MOPB025
Plasma based optics for electron beam fast micro-bunching
118
The utilization of plasma devices in beam transport is slowly being accepted as a worthy alternative thanks to its potential in maintaining or even reducing particle beams emittance but also for its compactness which supplements the recent advances in compact laser plasma acceleration systems. However, their use can go beyond the substitution of magnets. In this work, the utilization of a low density plasma device to micro-bunch electron beams through a "cascade focusing" caused by the beam generated wake inside the plasma. In addition, specialized particle in cell tools to study such phenomena over long distance (>cm) taking advantage of relativistic reference frames is swiftly presented. Such devices present a great potential for shortening future FEL facilities and increasing the efficiency of current.
Paper: MOPB025
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB025
About: Received: 29 May 2025 — Revised: 30 May 2025 — Accepted: 01 Jun 2025 — Issue date: 10 Jul 2025
MOPB028
Maximizing the hard-X-ray performance of SwissFEL by systematic re-alignment and recalibration of the Aramis undulator line
122
Aramis, the hard-X-ray undulator line at the free-electron laser SwissFEL at the Paul Scherrer Institute, has been in user operation at full beam energy since the end of 2018. After steady improvements of the performance until 2022, it proved difficult to maintain the achieved performance level in recent years. Now, after a systematic re-alignment and recalibration of the undulator line and a subsequent optimization of all relevant machine parameters, we have reached a new record photon pulse energy of 1 mJ at 12 keV photon energy. This contribution describes the steps taken and lessons learned to achieve and maintain this high level of performance.
Paper: MOPB028
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB028
About: Received: 28 May 2025 — Revised: 01 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 10 Jul 2025
MOPB030
Averaged FEL algorithm to simulate an arbitrary FEL polarization
126
FEL simulation codes are essential tools for simulating various FEL scenarios. Among the algorithms, the orbit-averaged algorithm is the most widely used due to its speed and low computational cost. The averaged algorithm simplifies physics model, so present codes such as GENESIS and SIMPLEX have limitations to model accurate features like FEL polarization and variations in electron beam current. Such details are possible when using an unaveraged algorithm (like PUFFIN). In this presentation we introduce an approach based on the averaged algorithm to simulate arbitrary FEL polarization and non-fixed electron beam current. Our method involves initializing all particles at the beginning of the simulation and performing particle calculations at each simulation step to account for the non-fixed electron beam. Additionally, arbitrary FEL polarization is calculated by modifying the FEL equations using the elliptical undulator formula and the GENESIS algorithm. Finally some demonstration will be shown comparing the performance of PAL-XFEL and results from other simulation codes to highlight the capabilities of this approach.
Paper: MOPB030
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB030
About: Received: 29 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPB033
A novel design of a magnetic chicane with positive R56
130
It has been attracting attention that the energy chirp, which is formed by the space-charge effect of the electron beam and the beam wake field when the beam passes through the accelerator tube, can be used to generate short-pulse XFELs. Since the energy chirp produced by this phenomenon is such that the energy of electrons in the rear of the bunch is lower than at the front, compression requires a magnetic chicane with a positive R56, which shortens the path of the lower energy electrons. On the other hand, a normal simple electromagnetic chicane would have a negative R56, not applicable to this bunch compression. In this presentation, we report on the idea of a compact R56-positive magnetic chicane that can be inserted in a straight section and the results of its design study.
Paper: MOPB033
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB033
About: Received: 27 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
MOPB034
Numerical simulation of on-axis helical undulator radiation using SCILAB-Xcos model
134
Abstract—A SCILAB Xcos model, developed using SCILAB software version 6.1.1, was implemented to simulate the on-axis radiation intensity of a helical undulator, (undulator parameter= 1, undulator wavelength 5cm, number of periods= 10, device length 0.6 m) with an electron beam (1, 2, & 3 GeV) and beam current as Ib = 3–6 × 10⁻⁶ Ampere. A numerical approach is utilized to perform the undulator radiation intensity calculations. The computed results were validated by comparing the on-axis undulator radiation intensity with those obtained from SPECTRA, an open-source synchrotron radiation (SR) calculation software.
Paper: MOPB034
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB034
About: Received: 13 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPB035
Towards gamma-ray free-electron lasers
138
The free-electron laser (FEL), powered by an accelerator and equipped with an undulator, produces intense coherent radiation at ever-shorter wavelengths. Whilst the hard x-ray regime represents the current state of the art, the gamma-ray regime remains the next objective. Gamma-ray lasers, deemed one of the most profound and intriguing challenges in physics by the 2003 Nobel Laureate, hold the key to unlocking the largely unexplored nuclear domain. This article introduces a novel scheme that harnesses FEL harmonics, offering a pathway for existing x-ray FELs to operate as gamma-ray lasers.
Paper: MOPB035
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB035
About: Received: 15 May 2025 — Revised: 01 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
MOPB037
Orbit alignment study in the collimation section at the European XFEL
142
Orbit alignment plays an important role in free-electron laser (FEL) facilities, particularly in the collimation section, where multipoles are strategically positioned near the collimators as part of the specialized optics design. At the European XFEL, a strong dependence of lasing performance on the orbit in the collimation section has been observed. This study focuses on calibrating the central positions of the collimators using an orbit bump scanning technique combined with beam loss detection. Additionally, the influence of orbit alignment in the collimation section on lasing performance was systematically investigated, offering valuable insights into optimizing FEL operation.
Paper: MOPB037
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB037
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
MOPB038
Bayesian optimization for generating attosecond X-ray FEL pulses
146
Ångström and attosecond represent fundamental spatiotemporal scales for studying electron dynamics in various materials. Recently, high-power attosecond hard X-ray pulses have been successfully demonstrated at the European XFEL using the self-chirping operation mode. However, the current process heavily depends on manual tuning by experienced operators, which is time-intensive and less scalable. In this work, we report recent advancements in automating and optimizing the generation of high-power attosecond X-ray pulses using Bayesian optimization techniques. By leveraging machine-learning-based approach, we aim to enhance pulse energy, spectral quality, and operational efficiency, paving the way for more accessible and reproducible attosecond X-ray experiments.
Paper: MOPB038
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB038
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
MOPB040
Leveraging the capabilities of LCLS-II: linking adaptable photoinjector laser shaping to x-ray diagnostics through start-to-end simulation
150
SLAC’s LCLS-II is advancing towards MHz repetition rate attosecond X-ray pulses, creating opportunities to optimize X-ray generation through machine-driven controls and diagnostics via start-to-end simulation. Advanced laser shaping and upconversion techniques at the photoinjector, such as spatial light modulator-based pre-amplifier pulse shaping linked to nonlinear methods such as dispersion-controlled nonlinear synthesis or four-wave mixing, enable precise electron bunch control at the source. Downstream, diagnostics like the Multi-Resolution COokiebox (MRCO)—a 16-channel time-of-flight spectrometer—characterize X-ray pulse profiles, providing real-time feedback on attosecond X-ray pulses or attosecond X-ray substructure. We present developments towards a framework linking programmable photoinjector laser shaping to X-ray diagnostics, enabling data-driven optimization of the X-ray source. This approach combines machine learning, high-throughput feedback, and advanced control to align LCLS-II capabilities with experimental goals, laying the foundation for optimization of attosecond-scale precision in X-ray experiments.
Paper: MOPB040
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB040
About: Received: 30 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
MOPB041
CW SRF gun generating beam parameters sufficient for CW hard-X-ray FEL
154
SRF CW accelerator constructed for Coherent electron Cooling project at Brookhaven National Laboratory frequently demonstrated record parameters using 1.5 nC 350 psec long electron bunches, typically compressed to FWHM of 30 psec using ballistic compression. In this paper we report experimental demonstration of CW electron beam with parameters fully satisfying all requirements for hard-X-ray FEL and significantly exceeding those demonstrated by APEX LCLS II electron gun. The most remarkable part of this achievement in this experiment that we used 10-years old SRF gun with modest accelerating gradient ~ 15 MV/m, a bunching cavity followed by basilic compression to generate 50 pC, 15 psec electron bunches with normalized emittance of 0.15 mm mrad and normalized project emittance of 0.2 mm mrad. In other words, we are presenting alternative method of generating CW electron beams needed for hard-X-ray FELs using existing and proven accelerator technology. We present description of the accelerator system setting, details of projected and slice emittance measurements as well as relevant beam dynamics simulations.
Paper: MOPB041
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB041
About: Received: 30 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
MOPB042
Conclusions from the UK XFEL conceptual design and options analysis study
157
UK XFEL is a multi-stage project to pursue ‘next-generation’ XFEL capabilities, either through developing a new facility in the UK or by investing at existing machines. The project’s Science Case envisages a step-change increase in the number of simultaneous experiments, with transform-limited (‘laser-like’) x-rays across a wide range of pulse durations and photon energies (up to ~20 keV) being delivered together with an array of synchronised sources, at high repetition rate to approximately ten FELs (evenly spaced pulses at approximately 100 kHz per experiment, with flexibility). A subset of applications require increased pulse energy and higher photon energies at low repetition rate or in short bursts. The project is now in the final year of its three-year conceptual design and options analysis phase, in which it has produced a conceptual design to efficiently meet these requirements, as well as conducting an analysis of the costs, socio-economic factors, and sustainability of the different investment options. The conclusions of this study are expected to be of general interest to the community.
Paper: MOPB042
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB042
About: Received: 28 May 2025 — Revised: 01 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
MOPB059
Improvements in FLASH operation through the use of the laser heater
183
FLASH is an XUV and soft X-ray free-electron laser (FEL) facility that comprises a superconducting linear accelerator with a beam energy of up to 1.35 GeV which drives two FEL beamlines in parallel and the plasma wakefield accelerator experiment FLASHForward. Within the upgrade program FLASH2020+, a laser heater was installed upstream of the first bunch compression chicane to mitigate microbunching instability in the linear accelerator by a controlled increase of the uncorrelated energy spread. The effect of the laser heater on microbunching instability and final energy spread has been verified with a transverse deflecting structure. In this paper, we describe the layout of the laser heater and report on improved operational aspects. It has been shown that the laser heater eliminates coherent contributions to visible transition radiation in transverse beam size measurements and, thus, contributes to better electron beam matching. In addition, an increase in the FEL output power is demonstrated, especially for first operation of the 3rd harmonic afterburner with variable polarisation.
Paper: MOPB059
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB059
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
MOPB060
Generation of short current spikes by laser modulation at FLASH
187
Generating few- or sub-femtosecond radiation pulses in a free-electron laser (FEL) requires precise control of the longitudinal phase space density of the driving electron bunch, as the FEL process depends strongly on the bunch current and energy spread profile. In an experiment conducted at FLASH in Hamburg, Germany, an energy modulation with linearly changing amplitude is imprinted onto part of the bunch by a laser pulse in an undulator upstream of the first bunch compression chicane. In subsequent longitudinally dispersive sections, a short current spike is created, as the linearly modulated region is compressed more strongly than the rest of the bunch. Measurements with a transverse-deflecting X-band cavity verify the creation of a short current spike, whose duration falls below the temporal resolution of the measurement setup of approximately 7 fs.
Paper: MOPB060
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB060
About: Received: 28 May 2025 — Revised: 30 May 2025 — Accepted: 30 May 2025 — Issue date: 10 Jul 2025
MOPB061
Experimental study on soft X-ray generation via Inverse Compton Scattering at CERN
190
This study explores the feasibility of using Compton Backscattering (CBS) as a compact source for generating photons in the extreme ultraviolet (EUV) to soft X-ray range, with potential applications in biological imaging and modern lithography. A CBS experiment was conducted at the AWAKE Run 2c test injector (ARTI), where electron bunches, accelerated up to 6 MeV by a high-gradient, brazing-free S-band photogun were collided with 1030 nm infrared pulses from the PHAROS femtosecond laser. The electron and laser beamlines were optimised for maximum CBS photon flux.
Paper: MOPB061
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB061
About: Received: 15 Apr 2025 — Revised: 01 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
MOPB071
Simulation study on fast beam-based alignment for commissioning of light sources
204
Beam based alignment (BBA) plays an important role in the commissioning of the light sources. To speed up the BBA, a BBA method using AC excitation, called fast BBA (FBBA), has been proposed and is tested in several existing light sources. In the FBBA, the beam orbit is sinusoidally modulated at around 10Hz by AC correctors, and the change in the beam response when a target quadrupole magnet strength is changed is measured using fast beam position monitors (BPM) at about 10kHz. To apply FBBA to light source commissioning, a simulation study of FBBA using random variables as response functions was performed to calculate the optimal corrector strength and variation of the strength of a quadrupole as a function of the BPM noise. We also improved the FBBA and found that a new FBBA scheme using two AC correctors of different frequencies separated by 1/2π betatron phase for one plane (horizontal or vertical) can suppress the BPM offset error by up to 10.
Paper: MOPB071
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB071
About: Received: 28 May 2025 — Revised: 01 Jun 2025 — Accepted: 01 Jun 2025 — Issue date: 10 Jul 2025
MOPB093
Study on pre-bunched free electron laser in the terahertz wavelength range
232
We have been studying about a pre-bunched FEL in the THz region. In the pre-bunched FEL, the electron bunches being compressed shorter than the oscillation laser wavelength, it is expected that we can generate short-pulse THz laser pulses with high peak intensity. A broadband spectrum and high-intensity characteristics, which cannot be realized by conventional FEL, are expected. The pre-bunched FEL experiments were conducted using the THz-CUR at Kyoto University Free Electron Laser (KU-FEL) consists of an existing electron rf gun (ECC-RF-Gun), which can produce short electron bunches adequate for pre-bunched FEL, and a 10-period undulator. We installed an optical cavity and performed beam tests at the lasing frequency of 0.2 to 0.4 THz. As the results of beam test, we observed the coherent stacking of coherent THz pulses inside the cavity, however, FEL oscillation has not been achieved yet. We will report on our pre-bunched FEL project, experimental setup, beam test results and future prospects.
Paper: MOPB093
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB093
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
MOPB105
Simulation and optimization of a sub-THz Cherenkov FEL at AREAL
246
A circular waveguide lined with a thin dielectric layer enables electron bunches propagating within the structure to radiate light in the (sub-)THz regime. In this work, we perform simulations of low-energy electron beams traversing extended waveguides to analyze the dynamics of beam bunching and lasing within the structure. By exploring the free-electron laser (FEL) process in this context, we demonstrate the potential of waveguides as a cost-effective alternative to undulator-based FELs. The study employs a simulated model of the AREAL LINAC at the CANDLE SRI to demonstrate these effects and provide realistic results. The simulations are performed using the space charge tracking algorithm ASTRA and the wakefield solver ECHO. For optimization of the system, the genetic optimization algorithm GIOTTO is applied to refine both the waveguide and accelerator variables. Using a 4 MeV electron beam with a charge of 300 pC, the optimized setup achieves a radiation frequency of 100 GHz with energy outputs exceeding 20 µJ in a waveguide of only 1.2 meters length. These results underscore the feasibility of this method, offering a innovative pathway to produce intense THz radiation.
Paper: MOPB105
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB105
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPB106
Optimizing Cherenkov waveguide seeding for THz SASE FELs towards stable, few-cycle pulses
250
The PITZ facility at DESY in Zeuthen has demonstrated the first operational high peak and average power THz self-amplified spontaneous emission (SASE) free electron laser (FEL). The current setup displays the onset of saturation at a central frequency of 3THz using a 3.5m long LCLS-I undulator. However, the THz user community has expressed the need for carrier-envelope phase (CEP) stability and the availability of few-cycle THz pulses to complement the currently demonstrated long pulses. In this work, simulations are conducted to evaluate and optimize FEL performance by incorporating a Cherenkov waveguide to seed the process. The waveguide parameter space is scanned to vary energy modulation depth and frequency, after which the performance is estimated using the space charge tracking algorithm, ASTRA, and the FEL simulation code, Genesis1.3. The optimized parameters allow saturation to be reached much earlier, while also significantly increasing the shot-to-shot stability. Down the line, the implementation of such a scheme would facilitate generation of few-cycle, CEP-stable THz pulses to be used in user experiments.
Paper: MOPB106
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB106
About: Received: 28 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPB108
Coherent undulator radiation with account of the beam energy spread
254
When a microbunched beam is sent to a resonantly tuned undulator it radiates coherent radiation with the intensity propotional to the bunching squared of the beam. According to *, the radiated energy increases with the undulator length. This conclusion, however, is only valid if one ignores the energy spread of the beam (and also the beam angular spread). The finite energy spread smears the microbunching, ultimately suppressing coherent radiation beyond a certain distance. In this work, we calculate the radiation of a microbunced beam with an energy spread and find the maximum energy that it can radiate coherently.
Paper: MOPB108
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB108
About: Received: 22 May 2025 — Revised: 30 May 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
MOPB110
Research plans for the University of Hawai’i Accelerator and Free-Electron Laser Lab
257
The accelerator and free-electron laser (FEL) laboratory at the University of Hawai’i at Manoa (UHM), established by John Madey, has been in standby since his passing in 2016, with operations further paused during the pandemic. Recent efforts aim to recommission the facility, which includes a thermionic gun, an S-band linear accelerator reaching 45 MeV, and a Mark III undulator FEL oscillator producing tunable infrared light. Previously, 3 μm infrared light from this undulator demonstrated the capability to generate 10 keV X-ray photons via inverse Compton scattering. Current upgrades include enhancements to vacuum systems and linac controls. Future plans focus on enhancing cathode performance, developing 3D FEL simulations for superradiance studies, achieving phase coherence with interferometer optics, and using waveguides for THz generation. Recent GINGER simulations explored FEL oscillator output under varying Desynchronization conditions, demonstrating pulse train formation. The revived UHM accelerator will advance FEL science and train the next generation of researchers.
Paper: MOPB110
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB110
About: Received: 23 May 2025 — Revised: 02 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPB118
Sub 100 keV hard X-ray inverse compton sattering experiment at BNL ATF
261
Recent progress on the experiments of Inverse Compton Scattering (ICS) at Brookhaven National Laboratory Accelerator Test Facility (BNL ATF) is introduced. Nominal e-beam parameters utilized are electron beam energy of 70 MeV, charge per pulse of 0.5 nC with normalized emittance of 2 mm mrad. Use of long wavelength TW CO2 laser, and short wavelength Nd: YAG or Ti: Sapphire lasers allows us to explore unique nonlinear dynamics of Compton scattering such as Bi-Harmonic interaction and emission of Orbital Angular Momentum of X-ray. Currently, up to 90 keV hard X-ray yield from counter collision of Nd: YAG laser and 70 MeV electron beam is in a range of 1E6 photons per single pulse. Planning to increase electron beam energy to achieve establishment of sub 100 keV ICS to provide sufficient photon flux density, in the range of 1E10 per pulse, owing to the long wavelength multi TW CO2 laser and tighter electron beam focus is underway.
Paper: MOPB118
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB118
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPM013
Modelling resonant depolarisation
298
For the FCC-ee collider it is planned to, in regular intervals (minutes), measure the average beam energy of the circulating electron and positron beams with a relative precision of $10^{-6}$ or better, using the method of resonant depolarisation with pre-polarized pilot bunches. In this article, we study basic systematic effects and ultimate uncertainties that may arise in this kind of measurement. To do so, we carry out simulations for a simple model representing an ideal situation, where an ensemble of particles with energy spread is subjected to synchrotron oscillations and to perfect spin motion. We assume an initial spin orientation in the vertical direction for all particles. The behavior of the spin is explored as an exciter frequency is swept slowly or rapidly, and in either direction,through the spin resonance.
Paper: MOPM013
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM013
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
MOPM040
Optimized physics performance evaluation of monochromatization interaction region optics for direct s-channel Higgs production at FCC-ee
406
The measurement of electron Yukawa coupling ($y_{e}$) via direct *s*-channel Higgs production at $\sim$125 GeV centre-of-mass (CM) energy is significantly facilitated at the FCC-ee, provided that the CM energy spread can be reduced to a level comparable to the natural width of the Higgs boson. This reduction is possible through the “monochromatization” concept, which involves generating opposite correlations between spatial position and energy deviation in the colliding beams. Following initial parametric studies for this collision mode, three different interaction region optics designs, each featuring nonzero horizontal, vertical, or combined dispersion at the interaction point, have been proposed based on the Version 2022 of the FCC-ee Global Hybrid Correction optics. In this paper, we benchmark the upper limits contours on $y_{e}$ with simulated CM energy spread and luminosity using Guinea-Pig, in order to assess, optimize, and compare their physics performances.
Paper: MOPM040
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM040
About: Received: 28 May 2025 — Revised: 06 Jun 2025 — Accepted: 06 Jun 2025 — Issue date: 10 Jul 2025
MOPM068
FCC-ee radiation environment and shielding
482
The secondary radiation fields generated by synchrotron photons pose a significant challenge for equipment in high energy electron and positron storage rings like the Future Circular Collider (FCC-ee) at CERN. The annual ionizing dose can reach MGy-levels in the FCC-ee tunnel and requires the design of a dedicated radiation shielding enclosing the photon stoppers in dipoles. In this paper, we present a first optimization of the shielding design, taking into account different aspects such as shielding efficiency, engineering and integration constraints, raw material costs, and radiological considerations. We demonstrate that the proposed shielding solution can decrease the dose in the tunnel by about two orders of magnitude, which considerably reduces the need of expensive radiation-hard equipment. In addition, we explore the option of housing accelerator electronics in a dedicated bunker near lattice quadrupoles, which can possibly allow for custom-off-the-shelf-based radiation tolerant electronics systems. We quantify the expected radiation levels in this bunker, which are driven by photo-neutron production by the high-energy component of the synchrotron spectrum.
Paper: MOPM068
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM068
About: Received: 27 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPM072
Status of the DELTA synchrotron light source
494
DELTA, a 1.5-GeV electron storage ring facility operated by TU Dortmund University in Germany, celebrated its 30th anniversary in fall 2024. During its time in operation, the facility has been continuously developed to provide synchrotron radiation (SR) users with the most reliable and attractive radiation source possible. This includes continuous improvements of electron beam stability and lifetime, the installation of a new 7-T superconducting wiggler magnet with a specially adapted SR outlet chamber, as well as the integration of a second solid-state amplifier-driven radiofrequency system. In recent years, there have also been many exciting developments in the field of accelerator physics. These include the construction of a facility for generating ultrashort and coherent SR pulses, studies involving laser-induced terahertz radiation, and experiments conducted in single-electron mode that complemented ongoing research activities. Furthermore, projects focusing on intelligent system control using machine learning methods were successfully implemented. This report summarizes the most significant developments over the past years.
Paper: MOPM072
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM072
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPM077
Commissioning of the new FLASHlab@PITZ beamline extension
498
Over the past year a new beamline dedicated to R&D for electron FLASH cancer radiation therapy and radiation biology was set up at the Photo Injector Test facility at DESY in Zeuthen (PITZ). The beamline runs in parallel to the SASE THz beamline at PITZ and is connected to it with an achromatic dogleg. The dispersion within the dogleg is utilized to install an aperture to scrape off-energy dark current. The following straight section of the beamline contains a kicker system which will be capable of distributing electron bunches from a single bunch train freely over an area of 25mm x 25mm within one millisecond. So far, only the slow kicker for the vertical plane is installed – the fast kicker for the horizontal plane will be installed soon. Behind an exit window is an experimental area for conducting irradiation experiments with the 22 MeV electron beam, which can accommodate setups for a wide range of experiments. Here we report the completion of the construction of the new beamline with detailed information about the setup. Preparation results of the PITZ robot and further data of the new experimental area are described. Additionally some new simulation results are given.
Paper: MOPM077
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM077
About: Received: 26 May 2025 — Revised: 31 May 2025 — Accepted: 31 May 2025 — Issue date: 10 Jul 2025
MOPM083
Status of the FLUTE RF system upgrade
517
FLUTE (Ferninfrarot Linac- Und Test-Experiment) is a new compact versatile linear accelerator at KIT. Its main goal is to serve as a platform for a variety of accelerator studies as well as a generation of strong ultra-short THz pulses for photon science. Also it will be used as an injector for a Very Large Acceptance compact Storage Ring (VLA-cSR) which will be realized at KIT in the framework of the compact STorage Ring for Accelerator Research and Technology (cSTART) project. To achieve acceleration of electrons in the RF photo-injector and linac with high stability, it is necessary to provide stable RF power. For this goal, an upgrade of the existing RF system design has been proposed and is currently being implemented. In this contribution an updated RF system design and the status of the RF photo-injector, linac and bunch compressor commissioning will be reported.
Paper: MOPM083
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM083
About: Received: 28 May 2025 — Revised: 30 May 2025 — Accepted: 30 May 2025 — Issue date: 10 Jul 2025
MOPM085
Towards ATF3: Beam based alignment (DFS, WFS) corrections in the ATF LINAC and ATF2 beamline
523
The Accelerator Test Facility 2 (ATF2) serves as a critical platform for testing technologies and techniques aimed at advancing the next generation of linear colliders. The ATF2 is composed of a linear accelerator (LINAC), a damping ring, and an extraction line that includes a high-precision final focus system designed to achieve the small beam sizes necessary for future collider experiments. A key requirement for these systems is maintaining high beam stability to deliver the nominal beam parameters at the interaction point, where tight beam focusing and minimal emittance are crucial for optimal collision performance. Recent efforts have focused on developing and implementing advanced beam correction techniques to enhance stability and counteract disruptive effects such as unwanted beam dispersion and wakefields to prepare for the ATF3 upgrade. These correction strategies have been tested across the LINAC, damping ring, and extraction line, showing promising results in mitigating these adverse effects. In particular, these methods have demonstrated the ability to reduce transverse beam oscillations and preserve beam quality, thereby improving the precision of beam delivery.
Paper: MOPM085
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM085
About: Received: 27 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPM089
Solid-state driven X-band linac for microcrystal electron diffraction
531
Transmission Electron Microscopes (TEM) require high voltage DC electron sources, which can quickly grow in size and cost at the higher energies required for standard TEM imaging. We present the progress on a low cost, compact solid-state-driven RF linac to replace high power electron guns in micro-crystal electron diffraction setups. The system accelerates electrons to 50 keV electrons with a 4 cell standing wave structure, where each cell is individually powered by an X-band solid-state amplifier. Future expansions on this design could function as a compact (order of 1 meter) source of electrons up to 1 MeV.
Paper: MOPM089
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM089
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPM091
The European Spallation Source neutrino Super Beam project and physics performance
535
The goal of the ESSnuSB project is to precisely measure neutrino Charge-Parity Violation (CPV). The construction of the European Spallation Source, ESS, represents an outstanding opportunity for such project to take place. ESSnuSB has been funded from EU in the framework of H2020 (2018-2022) and Horizon Europe (2023-2026) to make feasibility studies. The aim of the first phase was to demonstrate that the ESS linac can be used to generate an intense neutrino beam, which coupled with a megaton water Cherenkov detector placed in a mine 360 km from ESS, could allow the detection of neutrinos at the 2nd oscillation maximum. A CDR* has been published in which it is shown the unprecedented physics performance to precisely measure CPV. For this, the modification to compress the proton pulse length from 2.86 ms to 1.3 μs has been studied. The second, ongoing Design Study, ESSnuSB+, is devoted to neutrino cross-section measurements relevant to ESSnuSB. Two facilities are proposed, a low energy nuSTORM (muons decaying to neutrinos in a storage ring) and a low energy ENUBET (pions decaying to a muon and a neutrino and monitoring of the neutrino beam by detection of the decay muon).
Paper: MOPM091
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM091
About: Received: 20 May 2025 — Revised: 01 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
MOPM099
Accelerator and Compton gamma-ray source research program at Duke University
548
The accelerator and Compton gamma-ray source research program at Duke Free-Electron Laser Laboratory (DFELL), TUNL, is focused on the development of the storage ring-based free-electron laser (FEL) and a state-of-the-art Compton gamma-ray source, the High Intensity Gamma-ray Source (HIGS) driven by the storage ring FEL. With a maximum total flux of about 3.5E10 gamma/s and a spectral flux of more than 1,000 gamma/s/eV around 10 MeV, the HIGS is the world's highest-flux Compton gamma-ray source. Operated in the energy range from 1 to 120 MeV, the HIGS is a premier Compton gamma-ray facility in the world for a variety of nuclear physics research programs, both fundamental and applied. In this work, we will describe our recent FEL development to enable the production of gamma rays in the higher energy range from 100 and 120 MeV. We will also provide a summary of our recent activities in accelerator and FEL physics research and Compton gamma-ray source development.
Paper: MOPM099
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM099
About: Received: 05 Jun 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPM110
Target luminosity and luminosity integral achievement at VEPP-2000 collider
575
VEPP-2000 electron-positron collider operating in the beam energy range of 150-1000 MeV is the only machine originally designed to exploit Round Beams Concept which results in significant beam-beam limit enhancement. After long shutdown for injection chain upgrade VEPP-2000 resumed data taking with luminosity limited only by beam-beam effects. Thanks to extensive and thorough machine tuning the luminosity achieved L = 9 * 10^+31 cm-2s-1 at E=900 MeV that is above the design value. The stable operation resulted as well in high average data taking rate of 2-4 pb-1/day at top energies. In 2024 VEPP-2000 achieved the symbolic long-term milestone: integrated luminosity recorded by each of two detectors, SND and CMD-3, exceeded 1fb-1. This value was the target data volume written in the project physical program. Recorded data allows to study physics of light quarks with unprecedent precision. Recently published by CMD-3 collaboration e+e- -> pi+pi- cross-section measurement already changed the vision of muon anomalous magnetic dipole moment mystery - possible window to physics beyond the SM.
Paper: MOPM110
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM110
About: Received: 28 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPM114
Estimation of systematic errors in the experiment on precise mass measure of Y(1S)-meson on the VEPP-4M collider
579
Error analysis and estimation of accuracy in the experiment on precise mass measurement of Y(1S)-meson on the VEPP-4M with KEDR detector collider was presented. The resonant depolarization technique with laser polarimeter was used for beam energy calibration.
Paper: MOPM114
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM114
About: Received: 28 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPM115
Y(1S)-meson rest mass measurement on the VEPP-4M collider
582
A new high precision measurement of the Y(1S)-meson rest mass is being carried out at the VEPP-4M collider using the KEDR detector. The resonant depolarization method with the laser polarimeter has been employed for the absolute calibration of the beam energy. In the paper resent status of the experiment is discussed.
Paper: MOPM115
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM115
About: Received: 28 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPS003
Towards operational reality with laser assisted charge exchange
585
Laser-Assisted Charge Exchange (LACE) is being developed at the Spallation Neutron Source (SNS) as a potential replacement for injection foils, which are not expected to endure in the 10 MW beam power regime. Previous experimental demonstrations have achieved highly efficient charge exchange of H⁻ ions to protons for beam durations of up to microseconds. A refined method, capable of scaling to full millisecond duty cycles, has been experimentally validated and aligns with theoretical models. The current phase of development focuses on optimizing laser and beam parameters for LACE using a newly installed, flexible experimental setup in the High-Energy Beam Transport (HEBT) line at SNS. This setup takes advantage of the upgraded SNS beam energy of 1.3 GeV, offering greater flexibility in selecting laser wavelengths for the experiments. Simultaneously, efforts are underway to design a LACE ring injection system that fits within the spatial constraints of the existing SNS ring injection region. This presentation will provide an update on the progress of these developments.
Paper: MOPS003
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS003
About: Received: 23 May 2025 — Revised: 31 May 2025 — Accepted: 31 May 2025 — Issue date: 10 Jul 2025
MOPS004
Longitudinal hollow electron beam
588
The intra-beam scattering in high charge state intense heavy ion beams is a problem worth considering. With the help of controlling the longitudinal distribution of the ion beam, it may be possible to alleviate the ion beam loss and to improve the ion beam lifetime caused by intra-beam scattering. Unlike the traditional cooling process of direct current electron beams or longitudinal uniform distribution electron beams, a longitudinal hollow electron beam is used to cool heavy ion beams. Ions at the edge of the ion beam will receive stronger cooling, while ions at the center of the ion beam will receive weaker cooling, avoiding overcooling at the center of the ion beam. This paper discusses the generation, measurement, and related issues of longitudinal hollow electron beams. Corresponding solutions and suggestions have been proposed for the problems and challenges that may be encountered in the research. The cooling process of longitudinal hollow electron beams will be simulated and experimentally studied in the further, with the hope of obtaining beneficial effects.
Paper: MOPS004
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS004
About: Received: 09 May 2025 — Revised: 30 May 2025 — Accepted: 02 Jun 2025 — Issue date: 10 Jul 2025
MOPS027
Preliminary results from the CLEAR nonlinear plasma lens experiment
655
Plasma lensing provides compact focusing of electron beams, since they offer strong focusing fields (kT/m) in both planes simultaneously. This becomes particularly important for highly diverging beams with a large energy spread such as those typically originating from plasma accelerators. The lens presented here is a nonlinear active plasma lens, with a controlled focusing-strength variation purposely introduced in one transverse direction. This lens is a key element of a larger transport lattice, core of the ERC project SPARTA, which aims to provide a solution for achromatic transport between plasma-accelerator stages. We report on preliminary experimental results from the CLEAR facility at CERN, which aims to probe the magnetic field structure of the lens using an electron beam, in search of the desired nonlinearity, together with 2D plasma simulation results.
Paper: MOPS027
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS027
About: Received: 27 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
MOPS041
Status of the beam dynamics studies for the PERLE Energy Recovery Linac
702
PERLE (Powerful Energy Recovery Linac for Experiments) is a three-turn, high power Energy Recovery Linac under construction at IJCLab, France. It emerged from the design of the LHEC and FCC-eh and will serve as a hub for the validation of several technical choices and exploration of a broad range of accelerator phenomena in an unexplored operational power regime (up to 10 MW in its final version). Up to now, the final lattice design and phasing has been finalised. Current studies focus on non-linear effects and longitudinal dynamics. Also, the commissioning scheme is under developpement. We will present the status of the beam dynamics studies of the project, and highligth some of the ongoing studies
Paper: MOPS041
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS041
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPS053
Applications of electron energy measurement based on resonant spin depolarization at BESSY II
737
An electron energy measurement based on resonant spin depolarization has been running permanently at BESSY II for several years. This high-precision energy measurement was set up primarily for users of synchrotron radiation for me- teorological applications from the Physikalisch-Technische Bundesanstalt (PTB). Recent investigations have led to a better understanding of the method and the possibility of shortening the measurement time. This allows for new obser- vations and the use of the energy measurement for different applications such as the model-free measurement of the natural chromaticity, the momentum compaction factor or synchrotron sidebands.
Paper: MOPS053
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS053
About: Received: 27 May 2025 — Revised: 31 May 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
MOPS056
Single electron storage at UVSOR-Ⅲ electron storage ring
745
We have started single electron storage experiments since 2021 at the UVSOR-Ⅲ storage ring with the aim of conducting fundamental research on electromagnetic radiation. At BL1U, which is a beamline dedicated to light source developments, we extracted undulator light in the UV wavelength range into the air and observed its intensity by a photomultiplier tube, as decreasing the electron beam intensity using a beam scraper. When the beam intensity became sufficiently small, we observed step-function-like intensity changes with a good SN ratio, each of which corresponded to a loss of one electron. Based on this technique, we confirmed the single electron storage. After establishing the technique, we conducted some experimental studies on undulator radiation from single electron. We will present the latest results at the conference.
Paper: MOPS056
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS056
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
MOPS063
10 years operation of the Solaris storage ring
756
The SOLARIS storage ring, Poland’s first synchrotron light source, has marked a decade of successful operation, contributing significantly to scientific research and technological advancement. Commissioned in 2015 and inspired by the innovative design of Sweden’s MAX IV Laboratory, SOLARIS exemplifies the effectiveness of international collaboration in cutting-edge accelerator technologies. Over the past 10 years, the facility has maintained high performance and reliability (97% availability), delivering high-quality photon beams to researchers in diverse fields. Continuous improvements in the accelerator systems, such as enhanced beam stability due to SOFB and FOFB implementation, and optimised maintenance schedules, have enabled SOLARIS to meet the growing demands of the scientific community. A key focus has been the development of new beamlines and experimental stations, broadening the scope of available research capabilities. Looking ahead, SOLARIS aims to further expand its infrastructure (linac upgrade, top-up injection) and enhance beamline performance, ensuring its continued role as a hub for innovation and scientific excellence.
Paper: MOPS063
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS063
About: Received: 28 May 2025 — Revised: 30 May 2025 — Accepted: 31 May 2025 — Issue date: 10 Jul 2025
MOPS065
Physics-driven specifications for the EIC ESR magnet power supply ripple
760
To avoid unacceptable proton emittance growth via beam-beam interaction, the EIC electron storage ring (ESR) requires very stringent tolerances for beam position and size stability at the interaction point. These tolerances imply tight specifications for several accelerator systems, including magnet power supplies (PS). While the magnetic field ripple requirements are most stringent at the betatron frequency and harmonics, the main PS challenges occur below ~1 kHz, where the ripple attenuation due to the vacuum chamber is insufficient. In the original ESR dipole powering scheme with ~20 families, the dipole PS current ripple specifications were found to be near or beyond the state-of-the-art. A recently adopted scheme with a single ESR main dipole PS relaxes these requirements to ~10 parts per million (ppm) rms, which is achievable. Additionally, the vacuum chambers of non-standard cross-sections required at some dipoles must be modified to match the field penetration time constant to that of the standard vacuum chamber. The paper presents the physics reasoning and simulations behind the latest PS ripple specifications, ranging from 5 to 100 ppm rms, depending on the magnet type.
Paper: MOPS065
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS065
About: Received: 28 May 2025 — Revised: 01 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPS066
A Dipole Scheme for the Electron Storage Ring at the Future Electron-Ion Collider
764
The Electron-Ion Collider, which is currently being designed for construction at Brookhaven National Laboratory, will collide polarized electron beams (5-18 GeV) with polarized hadron beams (41-275 GeV) at luminosities up to 10^34 cm−2 s−1. The electron storage ring will contain about 750 dipoles. These dipoles must fulfill not only complex geometric constraints but also requirements set by spin polarization. 576 dipoles will be located in the arcs and arranged as super-bend triplets, which provide reverse bending at 5 GeV to increase the emittance and damping decrement. The rest will be situated in the interaction region and insertion regions around the ring. Tight orbit tolerances driven by beam-beam effects at the interaction point result in very tight field-ripple requirements. While these could be mitigated by powering all dipoles in series, due to the super-bend configuration the dipoles do not all scale similarly with energy. A novel scheme has been developed using variable-turn coil designs and trim coils to achieve the required fields across the energy range. This contribution presents the unique dipole layout developed for the electron storage ring.
Paper: MOPS066
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS066
About: Received: 28 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPS082
Simulation of the ion profile monitors in the Brookhaven AGS
782
Ion profile monitors (IPMs) provide a non-destructive means of measuring the transverse beam size of a passing ion beam in a particle accelerator. The Alternating Gradient Synchrotron (AGS) at Brookhaven National Lab is equipped with two types of IPMs: ion-collecting and electron-collecting. While ion-collecting IPMs are susceptible to significant distortions in the measured beam size due to the space charge of the passing beam, electron-collecting IPMs are much less affected. However, in the AGS, electron-collecting IPMs can only be operated periodically to preserve sensor lifespan, leaving ion IPMs as the sole source of consistent, real-time beam size feedback during operation. In this work, WarpX simulations of IPM operation are used to characterize the measured beam size as a function of beam parameters and IPM operating conditions. These simulations are then compared against experimental data collected from both ion and electron IPMs in the AGS. The findings aim to refine correction factors, enabling more accurate beam size estimations from ion IPM measurements, ultimately improving beam diagnostics and operational efficiency.
Paper: MOPS082
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS082
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPS128
User research at Brookhaven Accelerator Facilities Division
814
Brookhaven's Accelerator Facilities Division provides users with access to cutting-edge research tools, including the Accelerator Test Facility (ATF) and the Ultrafast Electron Diffraction (UED) facility. The ATF features an RF photocathode electron LINAC, a femtosecond Ti:Sa laser, and a high-peak-power LWIR laser, all capable of synchronized or independent operation. These tools enable advancements in beam manipulation, accelerator and laser technologies, and the study of low-plasma-density regimes for precise electron seeding into plasma cavities. This supports the development of low-emittance beams for compact laser wakefield accelerators (LWFAs), with applications in science and industry. The UED facility, equipped with an RF electron gun and Ti:Sa laser, facilitates dynamic studies of material structures and other low-energy electron beam research. Starting in 2025, access to these facilities will be available through the BeamNetUS program for academia, industry, and national labs. These unique research opportunities will be presented.
Paper: MOPS128
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS128
About: Received: 30 May 2025 — Revised: 02 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
MOPS135
Dynamic aperture studies for the EIC electron storage ring
817
The electron-ion collider (EIC), under design at Brookhaven National Laboratory, will consist of two storage rings for collisions of polarized electron and hadron beams. Dynamic aperture (DA) of 10 sigma is required in the electron storage ring (ESR) for the design beam energies from 5 GeV to 18 GeV to ensure an adequate beam lifetime. The DA is limited by chromatic and error effects in a strong optics with a low-beta interaction region. We present results of dynamic aperture studies for the latest ESR lattice (v6.3), which include compensation of non-linear chromaticity, the impact of field imperfections in dipoles, and the effects of dipole orbit.
Paper: MOPS135
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS135
About: Received: 29 May 2025 — Revised: 01 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
MOPS139
Status of VEPP-5 injection complex
829
The VEPP-5 injection complex was put into operation as a source of electronic and positron beams for the VEPP-2000 and VEPP-4M colliders at the end of 2016. To date, an operating energy of 430 MeV and a positron accumulation rate of 3.5 nC/s have been achieved. Options for improving the complex for working with promising installations are being considered. The latest results and prospects of operation are presented.
Paper: MOPS139
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS139
About: Received: 28 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
TUAD3
Injection into Resonance Islands
862
An Accelerator Physics Experiment (APEX) was conducted in the Relativistic Heavy Ion Collider (RHIC) to verify the formation, rotation, and size of resonance islands.The experiment provides lattice parameters to be used to facilitate an alternative method of transition crossing in the Hadron Storage Ring (HSR) of the Electron Ion Collider (EIC) project by producing a non-adiabatic kick to the off-axis beam within the island to displace the beam to the central closed orbit across transition. Proton beam was injected directly into an octupolar field driven stable resonance island in RHIC. This paper describes the procedures used to perform this Resonance Island Injection (RII) and discusses the experimental results.
Paper: TUAD3
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUAD3
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
TUYN1
Electron-Ion Collider status
878
The Electron-Ion Collider (EIC), which is being designed by BNL, JLab and other partners, will be a particle accelerator that collides electrons with protons and nuclei to produce snapshots of those particles' internal structure. It will collide polarized high-energy electron beams with hadron beams in the center-of-mass energy range of 20-140 GeV. The electron beam, employed as a probe, will reveal the arrangement of the quarks and gluons that make up the protons and neutrons of nuclei. The EIC will allow us to study the "strong nuclear force", the role of gluons in the matter within and all around us, and the nature of particle spin. This talk will describe the Electron-Ion Collider design and construction at Brookhaven National Lab.
Paper: TUYN1
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUYN1
About: Received: 28 May 2025 — Revised: 29 May 2025 — Accepted: 01 Jun 2025 — Issue date: 10 Jul 2025
TUCD3
Evaluation method and countermeasures for the beam loss in fourth-generation light sources
919
Unlike the situation under the third-generation light sources, we will have to pay more attention to control electron beam loss under the fourth-generation ones. The main causes of the beam loss are (i) a beam dumped by switching off RF cavities and (ii) electrons lost by electron-electron scattering (the Touschek effect). Due to the low emittance, if the highly-dense dumped beam directly hits a chamber, that will induce a vacuum accident. Due to the short beam lifetime, the number of scattered electrons hitting insertion devices (IDs) increases, and demagnetization would severely shorten the ID lifetime to be less than 10 years. Here we evaluate and elucidate how a dumped beam and scattered electrons are lost in the storage ring. To investigate the process of Touschek loss, we developed an analytical method following Piwinski’s formulation and calculated the spatial and energy distributions along the ring. Taking SPring-8-II as an example, our calculation indicates that a beam shaker is effective to reduce beam power density, and the installation of vertical scrapers in the long straight sections and shielding materials in the IDs can prevent the component damage of the ring.
Paper: TUCD3
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUCD3
About: Received: 28 May 2025 — Revised: 01 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 10 Jul 2025
TUCN2
Engineering magnetic carbon nanotubes via swift heavy ion irradiation for spintronics and quantum technologies: XAS and RAMAN study
925
Carbon nanotubes (CNTs), known for their versatility as 2D materials, are key to advancing quantum technologies such as qubit fabrication and magnetic data storage. In this study, multi-walled carbon nanotubes (MWCNTs) doped with magnetic impurities (Fe and Co) were exposed to swift heavy ion (SHI) irradiation to explore induced structural modifications. SHI beams transfer energy to the carbon matrix via electronic energy loss and thermal spikes, causing Fe and Co ions to agglomerate within interstitial regions and defect sites of the CNT matrix. Structural changes were analyzed using high-resolution X-ray diffraction (HRXRD), Raman spectroscopy, and near-edge X-ray absorption fine structure (NEXAFS). HRXRD revealed peak dissolution, reduced crystallinity, and increased lattice strain, while Raman spectra showed partial annealing of damaged CNTs with disorder parameter reduction (FeCNT: 0.65→0.57; CoCNT: 0.55→0.52). NEXAFS confirmed non-destructive processing. These findings link ion fluence with defect engineering, paving the way for magnetic CNTs in spintronics and data storage.
Paper: TUCN2
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUCN2
About: Received: 11 Jun 2025 — Revised: 12 Jun 2025 — Accepted: 14 Jun 2025 — Issue date: 10 Jul 2025
TUPB014
The Experimental Storage Ring (ESR) - recent developments
976
The Experimental Storage Ring (ESR) at GSI Darmstadt, Germany is the core instrument for unique physics experiments. It is operated for accumulation, storage, cooling and deceleration of a wide range of heavy ion beams in the energy range from 4-400 MeV/u coming from the synchrotron SIS18 via the FRagment Separator (FRS) or a direct transport line. Low energy decelerated beams can also be fast extracted to the storage ring CRYRING or to the HITRAP facility. The overview of the ESR performance, will be presented here. The features and challenges of the operation with the new control system LSA (LHC Software Architecture) will be outlined as well.
Paper: TUPB014
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB014
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
TUPB028
Development of the beam separation test device to evaluate the electric field of non-destructive electrostatic septum
1025
Slow beam the extraction in synchrotrons is utilized for various nuclear and particle physics experiments and radiology. A beam loss at a septum electrode induces equipment activation and damage. We have been developing a non-destructive electrostatic septum. This septum has multiple electrodes, and those are placed around the outside of the beam. Measuring the 2-D electric field distribution of this septum is important to evaluate the beam loss reduction due to this septum. We are developing the beam separation test device consists of a prototype septum, horizontal and vertical wire scanners and the electron gun installed on a movable stage fixed to a drive unit. This device measures the electric field by injecting an electron beam into the electric field and measuring the bending angle of the beam orbit. Since the width of the electron beam determines the resolution of the measurement data, we developed an additional lens system that can transport the beam 1.5 m with a width of 1 mm. We used a square chamber for the 2-D measurement system. A permalloy magnetic shield is installed inside the chamber and reduces the external magnetic field from 50 $\mu$T to less than 1.5 $\mu$T.
Paper: TUPB028
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB028
About: Received: 12 Apr 2025 — Revised: 29 May 2025 — Accepted: 30 May 2025 — Issue date: 10 Jul 2025
TUPB037
New linac designs by High Energy Sources R&D Group at Varex Imaging
1050
High Energy Sources R&D group at Varex Imaging has developed several Accelerator Beam Centerline (ABC) and Linear Accelerator (linac) designs in the past 8 years. Here we present a summary of our recent progress. M9V linac, featuring our new ABC, is being developed to further improve characteristics of 9 MeV accelerator. The new ABC is shorter than the standard 9 MeV linac, and the focusing solenoid is completely removed. The overall system design increases dose rate and reduces the weight and complexity. In addition, our new version of K15, called K15V or V15, is being redesigned with a hybrid Standing Wave (SW) and Traveling Wave (TW) reverse feed configuration, protected by US patent. We expect it to produce significantly higher dose rate of up to 40000 R/min at 1 m. The first SW section of this linac may be used separately in 9 MeV system we called V9, which is also expected to deliver higher dose rate of up to 20000 R/min while substantially reducing neutron yield compared to 15 MeV machine. We have also tested a new concept implemented on 6 MeV linac, which permitted reducing the electron beam focal spot size to 350±150 µm without utilization of any magnetic systems.
Paper: TUPB037
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB037
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
TUPB042
Optimising focusing parameters of very high energy electron beams for radiotherapy using Monte Carlo simulation
1063
Very high energy electron (VHEE) beams, with energies of 100 MeV and above, offer favourable properties for radiotherapy, such as deep penetration depth and reduced sensitivity to tissue heterogeneity. Numerous simulation and experimental studies have investigated these properties for clinical application. In this study, we use Monte Carlo simulation using TOPAS to obtain the depth-dose profiles of VHEE beams with varying energy and focusing parameters. An empirical model is fitted to the central axis dose, yielding parameters that characterise the depth-dose profile. A linear interpolator then maps these fitting parameters to the focusing parameters, allowing us to identify the optimal focusing parameters. The results presented here are independent of the beamline and can therefore guide the design of a final focusing systems for VHEE beams.
Paper: TUPB042
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB042
About: Received: 27 May 2025 — Revised: 30 May 2025 — Accepted: 31 May 2025 — Issue date: 10 Jul 2025
TUPB052
Laser wakefield accelerator-driven photonuclear reactions for the production of medical radionuclide 67Cu
1086
Recent results of production of the medical radionuclides 67Cu using a laser wakefield accelerator (LWFA) are presented. This emerging technique utilises powerful, ultrashort laser pulses that are focussed into a gas jet to create a plasma wake that traps and accelerates electrons to very high energies with large accelerating gradients. Accelerated electrons interact with high-Z material to produce high-energy photons by bremsstrahlung, which then produce 67Cu via the 68Zn(γ, p)67Cu photonuclear reaction. 67Cu, with 62 h half-life, is considered ideal radioisotope for treatment of lymphoma and colon cancer.* The production of 67Cu requires medium-energy (~70 MeV) protons that are only available at limited number of facilities. We present the experimental setup, maximising electron pulse intensity by optimising laser beam properties and target composition of gas jet. The gamma beam and the design of 68Zn are optimised using FLUKA simulations. We will also report on the development of detectors for online monitoring of the electron and gamma beams, and produced activities of the radionuclides.
Paper: TUPB052
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB052
About: Received: 29 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
TUPB055
Exploring the potential of accelerator-based neutron generators in modern research
1088
The Institute for Plasma Research in India set up an accelerator-based 14 MeV neutron generator utilizing Electron Cyclotron Resonance Ion Source technology. This advanced generator can produce 1012 neutrons per second in continuous and pulse modes. By directing deuterons at a TiT target, it generates fast neutrons that are essential for various applications such as fusion experiments, electronics testing, feasibility studies of medical isotope production, neutron radiography, etc. Various independent neutron diagnostics such as diamond detectors, proportional counters, and foil activation have been installed in the Neutron Generator. These techniques provide precise measurements of neutron flux, which are cross-checked with the associated alpha diagnostic technique to ensure accuracy. Additionally, lab-scale experiments at IPR have explored neutron irradiation for medical radioisotope production and radiation-induced damage in electronic components. This paper highlights the significance of precise measurement techniques and demonstrates the critical role of neutron generators in advancing research and practical applications, from medical isotopes to fusion neutronics studies.
Paper: TUPB055
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB055
About: Received: 26 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 10 Jul 2025
TUPB056
Development of a friendly high-energy irradiation environment for future space developments
1091
Effect assessments of high-energy radiations on materials and equipment are expected to become increasingly important in near future space developments. We initiated a project to construct an irradiation environment with high-energy radiations using the electron linear accelerator at Nihon University. The advantages of using this accelerator include the accelerations up to 100 MeV for high-energy and high-dose irradiations, its easy accessible location from Tokyo area. These advantages help many users including venture companies to use the irradiations with much less difficulties, that we consider as an important key to enhance future space developments. The electron linear accelerator sends electron beams with a wide energy range to the FEL line by bending them 90 degrees with two 45-degree bending magnets. Irradiation tests are planned to be conducted using the radiation produced in this process. In this study, we present a simulation result on the acceleration process of the electron beam and the amount of radiation generated by the 45-degree bending magnets. We also show dosimeter measurements by the high-energy irradiations to be compared with the simulation results.
Paper: TUPB056
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB056
About: Received: 29 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
TUPB057
Ultra-high spatial resolution in micron scale achieved by a practical cascade high energy electron radiography in HERPL
1095
As a new scheme, High Energy Electron Radiography (HEER) was considered as one of the novel mesoscale diagnostic methods for high energy density matter (HEDM) because of powerful penetration, high space-time resolution and large density dynamic diagnosis range. In this work, we R&D a practicle cascade HEER composed of a electromagnetic beamline and a permanent magnet HEER in High Energy Electron Radiography Research Platform in Lanzhou (HERPL). The field of view of the cascade HEER is about Φ3mm, and its total length is half that of the electromagnetic HEER with the same magnification. 50 MeV electron beams with picosecond pulse width bunch were used to image a TEM grid to study the spatial resolution. The excellent result was obtained with spatial resolution about 0.6 μm. In addition, electron bunch train and ultra-fast imaging acquisition system prepared for dynamic HEER were studied in this paper.
Paper: TUPB057
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB057
About: Received: 27 May 2025 — Revised: 01 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
TUPB065
Base features of electron cooling systems for NICA collider
1109
The project NICA (Nuclotron-based Ion Collider fAcility) aims to provide colliding beams for studying heavy ion collisions in the energy range 1-4.5 GeV/u. Obtaining maximum luminosity of the collider requires powerful longitudinal and transverse cooling at collision energy. That will be achieved with usage of both stochastic and electron cooling. The 2.5 MeV electron cooling system (ECS) includes two coolers, which cool ion beams in both rings simultaneously. The Budker Institute of Nuclear Physics (BINP SB RAS) already built and commissioned the electron cooling system for the NICA Booster with a maximum energy of 50 keV and now it develops the high voltage electron cooling system for the collider. This article describes the status of the ECS development.
Paper: TUPB065
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB065
About: Received: 26 May 2025 — Revised: 02 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
TUPB068
Density measurements and simulations on confined electron column in GL2000 Gabor-lens device
1120
GL2000 Gabor-lens (GL) is a 2m long device built mainly for focusing and space charge compensation of hadron beams in energy ranges up to GeV. The electron cloud is initially produced by cold-cathode method with gradually ionisation of residual gas and is confined in a cylindrical trap much longer compared to previous constructed lenses. Density measurements were carried out at the test-stand in Goethe University in 2024. Outgoing stream of residual gas ions was detected within cylindrical spectrometer mounted on axis outside of the lens. Due to the dependency of the kinetic energy on starting potential, the on-axis potential and therefore confined average charge density can be derived. Measured densities were evaluated in a range of $10^{14}$-$10^{15} m^{-3}$. A large scale multi-particles Monte-Carlo-PIC (particle-in-cell) simulations with electrons and ions were carried out to understand collective phenomena in non-neutral plasma and to use the latter for linear and non-linear beam manipulation. Measurements and simulation results will be presented.
Paper: TUPB068
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB068
About: Received: 28 May 2025 — Revised: 31 May 2025 — Accepted: 31 May 2025 — Issue date: 10 Jul 2025
TUPB100
Towards the detection of mixed helium and carbon ion beams using a gas-filled charge exchange cell
1151
Irradiation with mixed helium and carbon ion beams is emerging as a promising approach to treatment monitoring in ion radiotherapy. In contrast to mono-isotopic beams, the full characterization of the mixed beam requires distinguishing ion species of almost identical charge-to-mass ratio, which is not feasible with most conventional beam diagnostic devices. This proceeding proposes a measurement concept that could allow for determining the ion mixing ratio after extraction from the ion source at energies around 10 keV/u. The concept relies on a gas-filled charge exchange cell, where the traversing ions experience electron capture events, followed by an electrostatic or magnetic analyzer and beam intensity measurement. The proposal is accompanied by proof-of-concept measurements performed at the *Helmholtz Zentrum Dresden-Rossendorf (HZDR)*, which showcase the potential but also several challenges associated with the measurement concept.
Paper: TUPB100
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB100
About: Received: 27 May 2025 — Revised: 01 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
TUPM004
Simulations and experimental commissioning results of the AWAKE Run 2 photoinjector
1171
AWAKE (Advanced Wakefield Experiment) is the world’s first proton-driven plasma wake field acceleration experiment and has demonstrated the acceleration of electrons to several GeV’s in its first Run. The goal of Run2 is acceleration of a witness bunch whilst preserving beam quality and experiment scalability. AWAKE drives high gradient plasma wake fields using a proton beam, then a secondary electron beam is accelerated which is externally injected from a dedicated injector which consists of an S-band Rf-gun and an X-band bunching and acceleration system. This S band RF-Photoinjector for the AWAKE Run 2 experiment at CERN is currently being commissioned. The obtained experimental results are presented and compared to simulations in this paper. Overall, the commissioning demonstrates successful matching of beam parameters with the design values, supported by ASTRA simulations. This lays the groundwork for low emittance electron beam injection into the AWAKE plasma and opens possibilities for future high-gradient acceleration experiments.
Paper: TUPM004
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM004
About: Received: 19 May 2025 — Revised: 30 May 2025 — Accepted: 30 May 2025 — Issue date: 10 Jul 2025
TUPM005
Recommissioning of the University of Hawai‘i LINAC and Free Electron Laser
1175
The electron beam linear accelerator (linac) at the free-electron-laser (FEL) laboratory of the University of Hawai‘i at Mānoa, originally developed by Prof. John Madey, has undergone recommissioning. The S-band linac delivers 45 MeV electron beams with 170 mA pulse current and 4–8 $\mu$s pulse duration to drive an infrared FEL oscillator. Recent efforts include restoration of the microwave thermionic gun with a new LaB$_6$ cathode, upgraded vacuum and RF systems, and development of a Python-based beam dynamics model to recover operational magnet settings and optimize beam transport. These upgrades address key technical challenges to restart the accelerator and pave the way for future FEL experiments, including coherent pulse shaping and inverse Compton scattering x-ray generation.
Paper: TUPM005
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM005
About: Received: 27 May 2025 — Revised: 02 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
TUPM007
Field emission and unwanted beam propagation simulations in the SRF gun at SEALab
1179
The ideal beam coming from an RF photoemission electron gun is composed only of electrons that are produced by the incidence of the drive laser in the photocathode. The timing of the drive laser with respect to the RF fields in the gun is carefully chosen to tailor the beam properties. There are, however, sources of unwanted electrons that degrade the performance of RF photoemission guns. Field emission in superconducting radio-frequency (SRF) guns contributes to unwanted electron generation, known as dark current. This work presents simulations based on the Fowler–Nordheim (FN) model~\cite{FN} to study field emission in the SEALab SRF gun cavity. By analyzing 2D field maps and using ASTRA simulations~\cite{Astra}, emission hotspots are identified, and particle trajectories are evaluated. While most field-emitted electrons are lost within the cavity, a small but significant portion escapes, contributing up to 25\% of the emitted power. The analysis offers key insights into mitigating performance-limiting effects in SRF guns.
Paper: TUPM007
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM007
About: Received: 27 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
TUPM010
First THz light generated in high energy section of FLUTE
1186
FLUTE is a compact and flexible linac-based accelerator test facility at the Karlsruhe Institute of Technology (KIT) in Germany. It serves as a platform for a variety of accelerator studies and to generate intense short THz pulses for various photon science experiments. Later, FLUTE will be also used as an injector of sub-100 fs bunches into the VLA-cSR (Very Large Acceptance compact Storage Ring), which is part of the cSTART (compact STorage Ring for Accelerator Research and Technology) project currently in the technical design phase at KIT. Recently, FLUTE's high energy section has been installed and commissioned. This includes the linac, bringing FLUTE beyond 5 MeV to full energy, the bunch compressor, and two corresponding diagnostics sections. A metal foil in the last diagnostics section has been used to generate a first THz signal with high energy electron bunches.
Paper: TUPM010
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM010
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
TUPM016
Linac gun driver for the Swiss Light Source 2.0
1199
The Paul Scherrer Institute has developed advanced Linac gun driver electronics designed for use in Linear Accelerators, particularly for modern Synchrotron Light Sources. A prototype of this innovative gun driver was successfully evaluated during the final three months of user operations at the Swiss Light Source (SLS). The finalized design is now installed and will be integrated into the upgraded SLS 2.0, which is scheduled to undergo commissioning in 2025. The new gun driver is engineered to achieve extremely short electron bunch lengths, a key requirement for SLS 2.0 top-up operations. It delivers single pulses with the following specifications: 80 ps fall-time, 120 ps FWHM, and a -300 V peak amplitude, with a jitter of less than 5 ps. These enhanced performance parameters will facilitate a future redesign of the SLS Linac, making it more compact while further improving its functionality. This presentation will outline the implementation of the new gun driver and showcase the results obtained during its evaluation.
Paper: TUPM016
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM016
About: Received: 28 May 2025 — Revised: 31 May 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
TUPM020
An upgraded multiprobe surface analysis tool for photocathode research and development
1205
STFC Daresbury laboratory has developed a suite of analysis equipment for characterisation of photocathode materials. This includes the TESS spectrometer for measuring the mean transverse energy* and a multiprobe surface analysis system for measuring the chemical and physical properties of samples**. Recently, the multiprobe system has been upgraded to include a monochromated X-ray source which in conjunction with the high-resolution analyser should produce improved ability to resolve the chemical state of surface constituent atomic species. This could be particularly useful in the analysis of telluride and antimonide cathodes where incomplete reaction of the constituent species could significantly influence performance. The atomic force microscope has also been recommissioned giving access to surface topological information in the same vacuum environment. Finally, a new sample deposition chamber has been added which will allow additional deposition sources to be attached thus broadening the range of photocathode research that can be carried out.
Paper: TUPM020
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM020
About: Received: 23 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
TUPM021
An update of progress on the design of the diffraction line for the relativistic ultrafast electron diffraction and imaging facility at Daresbury Laboratory
1208
The Relativistic Ultrafast Electron Diffraction and Imaging (RUEDI) facility is an approved project to provide ultrafast capability to UK researchers. The current design involves two separate beamlines for diffraction and imaging but with shared infrastructure including laser pump sources. This presentation describes recent progress in the design of the diffraction line. The diffraction line has a 2.4 cell S-band RF gun to produce 4 MeV electron bunches. Bunch compression to the sub-10 fs range is carried out with a triple bend achromat design that also suppresses arrival time jitter*. Interchangeable sample chambers are planned to allow wide ranging experiments from both solid samples at room and cryogenic temperatures and liquid and gas targets. Post sample optics are provided to image the diffraction pattern on to a high-resolution single electron sensitive detector. Temporal diagnostics including an RF TDC and THz deflector are included along with a spectrometer at the end of this line to measure beam energy.
Paper: TUPM021
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM021
About: Received: 23 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
TUPM026
Advanced beam tuning and beam measurements techniques in the CLEAR facility
1216
The CLEAR (CERN Linear Electron Accelerator for Research) facility delivers to a wide user community a 200 MeV electron beam with highly flexible parameters. Running conditions range from single-bunch to multi-bunch operation, with bunch charges from 10 pC to 1 nC, bunch durations from 100 fs to tens of ps, and includes tunable momentum (30 MeV/c to 220 MeV/c). Such a variety of beam conditions poses a challenge to the beam instrumentation and to the beam measurements and tuning techniques, even more so given that quite often a rapid switch from one set of conditions to a very different one is required. In this paper we present several examples of the techniques developed in CLEAR for this purpose and discuss their advantages and limitations. Examples include emittance measurements and phase space reconstruction procedures by quadrupole scans and beam based alignment methods.
Paper: TUPM026
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM026
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
TUPM027
The future of the CLEAR facility: consolidation, ongoing upgrades and its evolution towards future electron facilities at CERN
1220
The CERN Linear Accelerator for Research (CLEAR) is a versatile 200 MeV electron linac followed by an experimental beam-line, operated at CERN as a user facility. Its user community includes research groups working on beam instrumentation R&D, advanced acceleration techniques and irradiation studies, including medical applications. A recent internal review has confirmed the excellence of its scientific output and its strategic interest for the laboratory, extending the facility operation until at least 2030. In this paper we discuss the consolidation actions needed for continued operation together with the ongoing hardware improvements and their impact on the future experimental program. These upgrades include a new front-end for the laser system allowing for a highly flexible time structure, better stability and higher repetition rates, plus the implementation of a second beam line whose optics has been designed to match user requirements and will provide additional testing capability. Finally, we discuss the potential role of CLEAR in the path towards future high-energy electron facilities at CERN.
Paper: TUPM027
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM027
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
TUPM029
Development of photo injector employing Yb fiber laser for stimulus super-radiant THz FEL
1224
THz wave is wonderful prove for materials. Additionally new nonlinear phenomena are expected in spintronic devices if the peak electromagnetic field is greatly higher than 10 MV/cm (3.3 T/cm). Although coherent transition radiation from short bunches is intense, it is very difficult to exceed 10 MV/cm. However we found a possibility of which oscillator FEL reaches ~100 MV/cm employing a pre-bunched configuration.* On a test accelerator (t-ACTS), we are going to introduce a photo-cathode to increase the bunch charge and synchronize with round-trip frequency of an FEL optical resonator. Currently t-ACTS supplies a bunch-charge of 5 pC, whereas the goal is to increase it more than 50 pC for the pre-bunched FEL. Since the intensity of coherent radiation is basically proportional to the square of the charge per bunch, increase of the bunch charge is much effective. The laser system includes a Yb fiber laser oscillator (wavelength: 1047 nm), a multi-pass amplifier, and a fourth harmonic generation (262 nm). A target synchronization accuracy is within 1 deg at 2856 MHz. The assembly of the oscillator has almost completed, and a work for synchronization with RF is on the way.
Paper: TUPM029
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM029
About: Received: 24 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
TUPM030
Analysis of laser-electron-radiation interaction in laser modulators for three SSMB scenarios
1227
Recent studies explored a novel storage ring light source using steady-state microbunching (SSMB). Existing investigations predominantly focused on single-particle and pure-optics phenomena. Many SSMB schemes employ laser modulators, comprising an undulator and copropagating laser beam, to manipulate electron longitudinal bunch length. Electron bunch traversing the undulator emits coherent undulator radiation near the resonant wavelength. Laser beams may form a closed path to become a laser enhancement cavity. We developed a model* analyzing laser-electron-radiation interactions in laser modulator cavities, considering mirror-induced losses, externally injected laser power compensation, and coherent undulator radiation dynamics on multiple turns. Our approach integrates beamline transfer matrices with a low-gain FEL oscillator model, enabling quick estimation of the dynamic effects. In this work we examine three SSMB scenarios, amplifier, frequency-beating, and harmonic, accounting for laser-electron-radiation interactions. Under preliminary design parameters, our analysis suggests feasibility for the three scenarios. A potential self-seeding SSMB scheme is also investigated.
Paper: TUPM030
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM030
About: Received: 23 May 2025 — Revised: 29 May 2025 — Accepted: 01 Jun 2025 — Issue date: 10 Jul 2025
TUPM032
Cherenkov waveguide design for THz production at the EuXFEL
1235
The EuXFEL R&D project, STERN, aims to provide X-ray users with an accelerator-based THz source synchronized with the X-ray repetition rate. The main proposed THz generation method consists of electron beam wakefield excitation in Cherenkov waveguides. This work focuses on the design of a copper block that holds an array of waveguides to cover the radiation spectrum spanning from 300 GHz to 30 THz. These will include a variety of lengths and dielectric layer thicknesses to vary the spectral contents of the excited TM modes. Additionally, driving the wakefield generation process with an off-axis electron beam causes the excitation of HE modes, which are of great interest to the user community and add to the spectral content of the THz pulse. To further increase pulse energy, the implementation of radiation incouplers is analyzed, demonstrating the potential for capturing the electron beams self-field completely. Such wakefield structures offer a novel option for delivering versatile THz sources tailored to next-generation pump-probe experiments.
Paper: TUPM032
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM032
About: Received: 27 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
TUPM035
Performance of terahertz-wave beamlines at Nihon University's laboratory LEBRA
1239
National Institute of Advanced Industrial Science and Technology (AIST) has collaborated with Nihon University to study generation of high-intensity terahertz waves using coherent radiations at the Laboratory for Electron Beam Research and Application (LEBRA) at Nihon University. In a straight section for parametric X-ray (PXR) generation, developments of various types of coherent radiation sources and a study of superimposed coherent radiation using a ring-type resonator have been conducted. Coherent edge radiation (CER) generated in the downstream bending magnet is transported to an experimental room using the PXR beamline and is used for spectroscopic measurements and imaging experiments in an acrylic box filled with dry air. In a straight section for an infrared free-electron laser (FEL), CER generated by a downstream bending magnet during FEL oscillations is extracted from an FEL resonator by a toroidal mirror with a hole.* The extracted CER is reflected by a sapphire substrate coated with Indium-tin oxide and transported to the room using an FEL beamline. In this presentation, the status of the two THz beamlines at Nihon University's laboratory LEBRA will be described.
Paper: TUPM035
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM035
About: Received: 26 May 2025 — Revised: 31 May 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
TUPM036
Feasibility study of a THz beamline design for the THz user facility at NSRRC
1243
Feasibility design of THz beamlines for the use of the superradiant THz free electron laser driven by the NSRRC high brightness photo-injector has been studied. The Accelerator Test Area (ATA) building, where the photo-injector installed, will be transformed into a THz user facility that meets radiation safety regulations. Narrow-band intense superradiant THz radiations with pulse energy as high as 20 μJ and tunable central frequency from 0.6 to 1.4 THz, generated by injecting an ultrashort electron beam into a U100 planar undulator, can be a useful tool for nonlinear and time-resolved pump-probe experiments. There will be two stages for user experiments. Phase I will be opened for users with the experimental station installed right after the THz sources in the accelerator tunnel. Another THz beamline, which is currently being designed to maintain the quality of THz radiations after propagation over longer distances, will be built for user experiments in Phase II. This report briefly describes the beamline design and the operation of user experiments in Phase I.
Paper: TUPM036
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM036
About: Received: 27 May 2025 — Revised: 29 May 2025 — Accepted: 01 Jun 2025 — Issue date: 10 Jul 2025
TUPM040
Molecular beam epitaxial growth of Sodium Antimonide photocathodes
1246
Cornell University has been working on developing techniques to grow single crystal photocathodes for electron sources using the Molecular Beam Epitaxy (MBE) technique. As a result, the first single crystal Cs3Sb photocathode was produced, which has shown high quantum efficiency and is expected to have a low Mean Transverse Energy (MTE). Now, other alkali materials are being explored. In this work, we report the epitaxial growth of Na-Sb photocathodes at the PHOtocathode Epitaxy Beam Experiments (PHOEBE) laboratory at Cornell University, employing a sequence of shuttered growth steps to form distinct unit cells. The photocathodes were characterized by Quantum Efficiency (QE) measurements and Reflection High-Energy Electron Diffraction (RHEED) patterns collected during growth. The RHEED streaky pattern shows angle dependence, confirming their single crystal structure. Notably, these Na-Sb photocathodes exhibited a QE exceeding 1% at 400 nm, which is much higher than previous reports on this compound. The possible reasons for this discrepancy are discussed.
Paper: TUPM040
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM040
About: Received: 29 May 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
TUPM046
Study on deposition method for improving quantum efficiency and lifetime of NEA-GaAs photocathode using cesium, antimony and oxygen
1256
Negative Electron Affinity (NEA) activated GaAs photocathodes are the only one capable of generating spin-polarized electron beam larger than 90%. However, the NEA layer currently made from mainstream cesium (Cs) and oxygen (O) is chemically unstable, the NEA-GaAs photocathode has a rapid quantum efficiency degradation over time or electron beam. As a result, it requires an operating vacuum pressure of below 10-9 Pa and has a short lifetime. Recently, a new NEA layer using heterojunctions with semiconductor thin films of alkali metals and antimony (Sb) or tellurium has been proposed. Recent works have shown that the deposition of the NEA layer was realized using cesium, antimony and oxygen. In this work, we attempted to introduce Sb at two different timing. One is introduction from the beginning, and the other one is introduction after Cs and oxygen deposition. We systematically investigate the deposition temperature and antimony thickness to find the optimal conditions for improving quantum efficiency and lifetime. We will report the latest results.
Paper: TUPM046
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM046
About: Received: 20 May 2025 — Revised: 03 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
TUPM048
Development of electronic orbit stability monitoring and analysis system in the Taiwan Photon Source
1259
The Taiwan Photon Source (TPS) storage ring features 172 strategically deployed Beam Position Monitors (BPMs) forming a high-precision electron orbit monitor-ing network. This paper presents an automated monitoring system that periodically extracts BPM data from the data-base and calculates standard deviations to quantify beam stability through statistical methods. The system employs a hierarchical filtering algorithm to identify BPMs with the highest standard deviations and generates analytical visualizations while tracking temporal trajectories of sig-nificantly varying BPMs. During the resolution of BPM electrode anomalous jumps, we developed and integrated a Q-value-based anomaly diagnostic method that effective-ly differentiates between BPM electrode anomalies and actual orbit variations. The system incorporates the LINE Bot API for real-time notification capabilities, establish-ing a comprehensive data acquisition-analysis-alert work-flow. Through its multi-level monitoring architecture, the system has successfully identified and resolved several critical issues affecting beam stability, including electrode abnormalities in BPM183 and BPM126, significantly enhancing source stability and providing users with more reliable beam quality assurance.
Paper: TUPM048
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM048
About: Received: 21 May 2025 — Revised: 02 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
TUPM049
Studying photoemissive properties of stable Cs-Sb compound thin-film photocathodes using a combination of Monte Carlo simulations and Density Functional Theory
1263
Cs-Sb compound thin-film photocathodes are an excellent candidate to produce bright electron beams for use in various accelerator applications. Despite the virtues of these photocathodes being known, the mechanics that govern their photoemission are not well-understood. Crystalline and other material properties affect the mean transverse energy (MTE) and quantum efficiency (QE) and, thus, the overall brightness. Electrons photoemitted from these thin-film crystals experience an unexpected energy loss similar to that found in bulk crystals despite their being a significantly shorter transport phase. Deeply understanding the relationship between the crystalline properties and the emitted electron beam’s brightness, as well as this drop in energy, is vital to generating ultra-bright electron beams for advanced accelerator applications. The purpose of this work is to use the Monte Carlo method to simulate photoemission from semiconducting films with electronic band structure parameters supplied by Density Functional Theory (DFT) calculations. This method is used to study all steps of photoemission and to identify the key parameters necessary for optimizing photocathode performance.
Paper: TUPM049
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM049
About: Received: 29 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
TUPM062
Status of S-PRESSO, A superconducting undulator for the European XFEL
1296
Up to six superconducting undulator modules are foreseen to be installed downstream with respect to the permanent magnet undulators of SASE2, one of the two hard X-ray lines at European XFEL. Aim is to provide users with photon energies above 30 keV. The superconducting undulator pre-series module (S-PRESSO) is currently under production.Before installation in the tunnel, the magnetic structures are characterized in the vertical He bath cryostat SUNDAE1 (Superconducting UNDulAtor Experiment), and in the horizontal test stand to perform quality assurance of the SCU coils installed in the final cryostat SUNDAE2. This contribution describes the status of the project.
Paper: TUPM062
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM062
About: Received: 01 Apr 2025 — Revised: 31 May 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
TUPM078
A proposal of superconducting RF electron gun with the latest 4K superconducting technology for CW high-brightness electron beam generation
1337
A superconducting accelerator is an excellent technology that can efficiently accelerate high-current beams and is being applied to free electron lasers and next-generation linear electron-positron colliders such as ILC. Not only for the fundamental science, but also the high current electron beam plays a rather important role in industrial and medical applications. This is because the demand for high-current beams is also strong in these applications. While superconducting accelerators are becoming more widely used, there are not many examples in practical use of the superconducting RF gun, such as the ELBE RF Gun in HZDR. The entire accelerator should be superconducting for its energy efficiency and technical compatibility. To bridge this technical gap, we propose a superconducting RF gun utilizing the latest 4K superconducting technology, which can generate continuous, high-brightness beams.
Paper: TUPM078
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM078
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
TUPM080
A portable muon source for artificial muon muography
1345
Muography is a useful technology for non-destructive inspection of a large-scale structure. Muography with cosmic ray muons has limitations such as low rates, particularly low muon rates in the horizontal direction, and energy spreading, which require long observation times and limit its resolution. Worldwide, large structures such as bridges built during the economic development period of the 1950s-1960s have reached the end of their useful life, and the principle of preventive maintenance is being applied to save the resources, by understanding their interiors and renewing them with priority given to structures that have deteriorated. At this time, a technology of non-destructive inspection applicable to such large structures is required, and Muography using a portable artificial muons source is a promising candidate for this purpose. In this presentation, the results of the investigation of the portable artificial muon source will be presented.
Paper: TUPM080
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM080
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
TUPM087
A high-efficiency dielectric wakefield energy booster for CLARA
1357
Structure-based wakefield acceleration, using dielectric-lined or corrugated waveguides, is a novel acceleration method currently being explored by several research groups globally. This technology facilitates the transfer of energy from a high-charge drive beam to a lower-charge main bunch with high accelerating gradients. In this study, we propose an energy booster for the Compact Linear Accelerator for Research and Applications (CLARA) at Daresbury Laboratory, utilising dielectric wakefield acceleration (DWA). Our simulation study optimises the drive beam and structure to achieve maximal energy efficiency across varying main beam energies, enabling the delivery of a main beam with adjustable charge and final energy. Additionally, we have considered the stability of both the accelerated and drive beams, selecting the geometry and layout of accelerating structures to maximise accelerated beam quality and mitigate the development of beam breakup instability in the drive beam
Paper: TUPM087
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM087
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
TUPM089
Twin-bunch modelling in linear accelerators for plasma wakefield acceleration
1361
Twin electron bunches accelerated by high-energy linacs are attracting increasing interest especially in twin free-electron laser (FEL) pulse generation and beam-driven plasma wakefield acceleration (PWFA) studies. High-energy linacs may benefit from plasma accelerators, where a trailing bunch is accelerated in GV/m fields in a plasma wave driven by the leading bunch. This could facilitate high-energy physics, as well as greatly increase the available photon energy range of existing FELs without increasing the footprint. Here, initial analytical studies of twin-bunch generation in FLASH accelerator are carried out. With the initial beam longitudinal phase space properly tuned by temporally shaping the photocathode laser, together with optimizing linac settings, high-quality twin electron bunches with tunable delay and simultaneous bunch shaping can be generated, which is essential for energy-efficient PWFA with low energy spread.
Paper: TUPM089
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM089
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
TUPM090
An energy recovery proton linear accelerator for muon production
1365
Muons have important applications in both scientific research and industry. In order to produce muons, an effective way is to use a high-power proton beam interacting with a targeting material. After the interaction, the proton beam is disposed of for other purposes. In this paper, we propose a new type of proton accelerator, an energy recovery proton linear accelerator, so that the high-energy proton beam can be reused to give its energy back to the accelerator. This substantially saves the operational cost of the accelerator and also avoids the burden of high-power beam dumps.
Paper: TUPM090
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM090
About: Received: 20 May 2025 — Revised: 31 May 2025 — Accepted: 31 May 2025 — Issue date: 10 Jul 2025
TUPM091
An optimization of the ILC E-driven positron source with the TPE algorithm
1369
The International Linear Collider (ILC) is a next-generation electron-positron collider based on the superconducting linear accelerator. Many positrons are required for the ILC because beams are not reused in linear colliders. Therefore, the ILC electron-driven (E-driven) positron source system should be designed to optimize efficient positron generation. In this study, we optimize the accelerator parameters including the booster linac RF phase and amplitude, ECS RF phase and amplitude, optics over the system, etc. by the black-box optimizer with TPE algorithm. The results of the optimization are presented.
Paper: TUPM091
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM091
About: Received: 30 May 2025 — Revised: 01 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
TUPM092
Design studies on a kHz–MHz repetition rate pulsed muon source based on electron accelerator
1372
Certain types of muon experiments, such as muon spin rotation techniques and muon lifetime measurements, require beams with repetition rates around 50 kHz for optimal statistical performance. However, existing facilities are limited to pulsed beams operating at 25-50 Hz or continuous beams, both constrained by the time structure of proton drivers. Despite ongoing efforts to optimize these proton time structures, significant limitations in flexibility persist. This work introduces an alternative approach to muon production using high-repetition-rate (kHz-MHz) electron beams generated by superconducting linacs at XFEL facilities. This method provides unique temporal characteristics, promising substantial improvements in beam precision, flexibility, and experimental efficiency. We present comprehensive particle tracking simulations for the design of a surface muon beamline and detailed Monte Carlo studies to optimize target materials and geometries. The results underscore the potential of electron-driven muon sources to complement muon-based fundamental and applied physics research while extending the capabilities of current and future XFEL facilities.
Paper: TUPM092
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM092
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
TUPM095
Coherent high-harmonic generation with laser-plasma beams
1379
Active energy compression scheme enables generating laser-plasma accelerator electron beams with a small relative slice energy spread, of the order of 10 ppm. When modulated by a laser pulse, such beams can produce coherent radiation at very high, about 100-th harmonics of the modulation laser wavelength, which are hard to access by conventional techniques. The scheme has a potential of providing additional capabilities for future plasma-based facilities by generating stable, tunable, narrow-band radiation.
Paper: TUPM095
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM095
About: Received: 06 May 2025 — Revised: 29 May 2025 — Accepted: 01 Jun 2025 — Issue date: 10 Jul 2025
TUPM096
Development of an achromatic spectrometer for a laser-wakefield-accelerator experiment
1383
The large gradients of plasma-wakefield accelerators promise to shorten accelerators and reduce their financial and environmental costs. For such accelerators, a key challenge is the transport of beams with high divergence and energy spread. Achromatic optics is a potential solution that would allow staging of plasma accelerators without beam-quality degradation. For this, a nonlinear plasma lens\* is being developped within the SPARTA\*\* project. As a first application of this lens, we aim to implement an achromatic spectrometer for electron bunches produced by a laser-wakefield accelerator. We report on progress in designing such an experiment.
Paper: TUPM096
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM096
About: Received: 16 May 2025 — Revised: 03 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
TUPM097
Study of electron density in capillary discharge plasma for laser plasma accelerator
1387
Laser-plasma accelerators have demonstrated the ability to accelerate high-energy electrons but require improved beam stability and repeatability for practical applications. Pre-formed plasma channels enhance the stability in Laser-Wakefield Accelerators by maintaining laser focus over longer distances, increasing energy transfer efficiency. The characteristics of such channels are highly dependent on capillary geometry, gas parameters, discharge setup, and repetition rate. This study investigates the electron density profiles in plasma from gas-filled capillary discharges. Using interferometry and Stark broadening, we measured profiles under varying conditions, achieving densities of (2-6)×10^18 cm^-3. In this presentation, we showcase the stability and uniformity of the plasma, highlighting its capability to preserve beam quality in high-energy, high-repetition-rate applications. This type of plasma source is a crucial technology for the plasma accelerator-based Free Electron Laser developed at ELI-ERIC as well as for the EuPRAXIA project. Also, we discuss the conceptual design of plasma diagnostics for providing 'real-time' information in high-repetition-rate applications.
Paper: TUPM097
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM097
About: Received: 27 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
TUPM099
Initial characterization of a laser-driven betatron radiation source in the EuAPS project
1391
Betatron radiation is the spontaneous emission of radiation produced by the betatron oscillations of electrons in a plasma during the Laser Wakefield Acceleration (LWFA) process. A high-intensity and ultra-short laser pulse is focused on a supersonic gas jet, simultaneously creating a plasma, injecting, and accelerating electrons, which then emit this radiation. In the framework of the EuPRAXIA project, EuAPS (EuPRAXIA Advanced Photon Source) will be the first user-oriented radiation source based on betatron radiation developed at LNF-INFN Frascati in collaboration with CNR and the University of Rome Tor Vergata. This radiation source has a wide range of applications, including materials science, medical and biological research. The user facility aims to deliver 1-10 keV photons using a compact laser-driven plasma accelerator operating in a self-injection mechanism, which occurs in highly nonlinear laser-plasma interaction. In this contribution, we present the expected parameters of the source and the result of several dedicated experimental campaigns conducted within the EuAPS project to provide the preliminary characterization of the x-rays betatron radiation source.
Paper: TUPM099
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM099
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
TUPM115
Simulation and developmental status for generation and detection of THz using coherent transition radiation technique in Delhi Light Source
1411
THz technology being a highly growing and potent field, finds use in a wide range of research applications. Delhi Light Source (DLS) at IUAC, New Delhi is at final stage of commissioning to produce intense and coherent THz radiation based on pre-bunched Free Electron Laser principle. As an addition to the narrowband undulator radiation, broadband Coherent Transition Radiation (CTR) will also be produced by passing femtosecond electron beam bunches through an Al foil . To generate the electron bunches with multi-micro bunch structure from the RF photo cathode gun, a state of the art femtosecond fiber laser system has been developed in collaboration with KEK, Japan. The generated electron beam bunches with energy up to 8 MeV is expected to produce CTR maximum up to few microjoule of energy. The multi-micro bunch structure increases the average CTR power. This paper reports the simulation results of the CTR showing the power, angular and frequency distribution produced from DLS facility. The schematic design and developmental status of DLS for generation and detection of THz CTR are also discussed.
Paper: TUPM115
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM115
About: Received: 27 May 2025 — Revised: 30 May 2025 — Accepted: 31 May 2025 — Issue date: 10 Jul 2025
TUPS003
Beamline to inject laser plasma accelerated electrons to a quasi-isochronous compact storage ring
1415
Laser plasma accelerators (LPAs) can produce high-energy electron bunches from short distances. Successfully coupling these sources with dedicated compact storage rings tuned to quasi-isochronous conditions would demonstrate the capture and storage of ultra-short electron bunches in a circular accelerator. Electron bunches generated from LPAs can have a correlated distribution in longitudinal phase space: a chirp, as well as comparably large angular divergence and energy spread. We, therefore, design a flexible beamline that can transport ultrashort bunches with large angular and energy spread to a ring. We have used the accelerator design programs OPA and MAD8 to build up optical model of a beamline. The line is composed of focusing and dispersion matching sections. A set of small angle bending magnets counteracts the dispersion created by injection septum of the storage ring and provides quasi-isochronous bunch transfer with a flexible value of longitudinal dispersion (R56).
Paper: TUPS003
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS003
About: Received: 24 May 2025 — Revised: 03 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
TUPS006
Proton-driven plasma wakefield acceleration for high-energy lepton beams
1422
Future colliders with discovery potential for particle physics rely on increasing the parton centre of mass (pCM) energy, with the recent P5 report calling for a 10 TeV pCM collider. However, the development of such schemes using conventional accelerator technology would result in ever-larger facilities. High-gradient plasma wakefields driven by proton beams allow the transfer of energy to a witness bunch over a short length scale, and so offer a potential method to transform high-energy proton beams into high-energy lepton beams while requiring relatively little additional civil engineering. The application of this concept to a Higgs factory driven by 400 GeV protons was recently proposed*. In the present work, we discuss the ongoing efforts to address the challenges to realising such a scheme**, and possible upgrade paths to particle physics applications beyond a Higgs factory.
Paper: TUPS006
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS006
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
TUPS009
Advancing plasma accelerator science: Insights from the EuPRAXIA Doctoral Network
1426
The EuPRAXIA Doctoral Network (EuPRAXIA-DN) trains the next generation of scientists in plasma-based accelerator technologies, addressing challenges in laser-plasma interactions, advanced beam diagnostics, and novel applications. This contribution highlights progress made in three critical areas: ) real‑time characterization of capillary discharge plasmas to stabilize laser‑wakefield accelera-tion, (ii) femtosecond‑precision X‑band low‑level RF (LLRF) control for the compact EuPRAX-IA@SPARC_LAB injector, and (iii) active‑plasma‑lens (APL)–based beam transport enabling extreme‑ultraviolet free‑electron‑laser (EUV‑FEL) operation within four me-ters of undulator. The innovative training elements with-in the network, such as the EuPRAXIA School on Plasma Accelerators held in Rome in April 2024 and upcoming EuPRAXIA Camps, are also discussed. It is shown how these foster knowledge exchange and skill development for the network's Fellows and the wider plasma accelera-tor community.
Paper: TUPS009
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS009
About: Received: 28 May 2025 — Revised: 31 May 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
TUPS010
Electron beam scattering in rubidium vapour at AWAKE
1430
The Advanced Wakefield Experiment (AWAKE) at CERN uses bunches from the CERN SPS to develop proton-driven plasma wakefield acceleration. AWAKE Run 2c (starting in 2029) plans for external on-axis injection of a 150 MeV electron witness bunch. The goal is to demonstrate emittance control of multi-GeV accelerated electron beams. Prior to injection, the electron witness bunch may have to traverse rubidium vapour. Since the beam must have the correct beam size and emittance at injection, it is important to quantify the effect of scattering. For this, first-principle estimates and the results from Geant4 simulations are compared with measurements of a ~20 MeV electron beam scattering in 5.5 m of rubidium vapour, showing good agreement. Building on this agreement, Geant4 simulations using the estimated AWAKE Run 2c parameters are performed. These predict that scattering will not increase the electron beam size or emittance
Paper: TUPS010
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS010
About: Received: 31 Mar 2025 — Revised: 30 May 2025 — Accepted: 30 May 2025 — Issue date: 10 Jul 2025
TUPS013
Ion-motion simulations of a plasma-wakefield experiment at FLASHForward
1442
In plasma-based acceleration, an ultra-relativistic particle bunch—or an intense laser beam—is used to expel electrons from its propagation path, forming a wake that is devoid of electrons. The ions, being significantly more massive, are often assumed to be stationary. However, both theory and simulations suggest that any sufficiently dense electron bunch can trigger ion motion, and its effect must be taken into account. We simulate beam-driven plasma wakefields to identify key features—such as longitudinally dependent emittance growth—that could be observed in an experiment using plasma and beam parameters from the FLASHForward facility at DESY.
Paper: TUPS013
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS013
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
TUPS018
Synthesis of efficient ordered sodium potassium antimonide photocathodes via molecular beam epitaxy
1450
Alkali antimonide photocathodes exhibit high efficacy as photoemissive materials in electron sources. This proceeding explores the fabrication of thin, ordered films of sodium potassium antimonide via molecular-beam epitaxy (MBE) at the PHotocathode Epitaxy Beam Experiments (PHOEBE) laboratory at Cornell University. Utilizing a sequential deposition technique, the photocathodes are characterized in terms of both quantum efficiency (QE) and crystal structure with the goal of reducing the chemical and physical roughness. A spectral response from 400 to 700 nm demonstrates oscillations resulting from optical interference within the (SiN) substrate. Reflection high-energy electron diffraction (RHEED) patterns confirmed the successful growth of ordered crystal structures for the first time in a sodium potassium antimonide photocathode. Additionally, we investigated the photocathodes' sensitivity to oxidation, revealing their relative robustness compared to CsSb or KSb photocathodes. Notably, the incorporation of higher partial pressures of oxygen during growth improved QE and extended the operational lifetime of the photocathodes.
Paper: TUPS018
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS018
About: Received: 29 May 2025 — Revised: 02 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
TUPS019
Beam dynamics optimization in high-brightness Photo Injector with various photocathode laser pulse shapes
1454
At PITZ, a comprehensive study is conducted to analyze the factors influencing emittance growth in the European XFEL (EuXFEL) continuous wave (CW) setup. Emittance growth due to space charge effects can be mitigated using advanced photocathode laser pulse shapes. To optimize beam quality, multiobjective optimization studies using ASTRA are performed, focusing not only on minimizing emittance but also on maximizing beam brightness for various laser temporal profiles and dura-tions. The optimization is initially carried out for the CW injector section planned for EuXFEL. The optimized cases are then further tracked through start-to-end (S2E) simulations to evaluate their behavior in the compression stages of EuXFEL. A comparative analysis of gaussian, flattop, ellipsoidal, and inverted parabolic laser profiles is presented, assessing their efficiency not only in terms of emittance but also in 4D and 6D brightness. Finally, the results of the optimized photoinjector setup and the beam properties after the final bunch compression will be presented.
Paper: TUPS019
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS019
About: Received: 06 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
TUPS021
Activation of GaAs with a Cs-Te thin film
1461
GaAs cathodes with thin-film Negative Electron Affinity (NEA) surfaces affixed have been used to generate spin-polarized electron beams for decades, but still suffer from short lifetimes. Heterojunction NEA surfaces have shown promise in improving cathode lifetimes, but further optimization of cathode activation and surface deposition is possible. Here we report the results of cathode activation with evaporative deposition of a CsTe surface performed at Hiroshima University.
Paper: TUPS021
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS021
About: Received: 28 May 2025 — Revised: 30 May 2025 — Accepted: 31 May 2025 — Issue date: 10 Jul 2025
TUPS024
Wafer-compatible photocathode plug design for high gradient RF photoinjector
1464
Single crystal alkali antimonide photocathodes have been shown to produce brighter beams than their polycrystalline counterparts. These single crystal semiconductors require a lattice matched substrate to be grown, but current INFN plugs lack the capability for this growth. To relieve this issue, we modified the INFN plug to hold a disk 1cm in diameter. This allows for studies of a wide range of advanced photocathodes and geometries on arbitrary substrates in high gradient photoinjectors. We show the modified design, analysis of the local field at the cathode and cavity detuning, and demonstrate the principle with a 1cm Yttrium disk.
Paper: TUPS024
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS024
About: Received: 05 Jun 2025 — Revised: 14 Jun 2025 — Accepted: 14 Jun 2025 — Issue date: 10 Jul 2025
TUPS047
Assembly and testing of a QWR for the new ISIS MEBT
1530
The quarter wave resonator (QWR, a.k.a. λ/4 resonator) for the new ISIS MEBT is a bunching cavity that longitudinally compresses the H- beam into smaller bunches. It has two gaps with a distance of βλ/2 between mid-gaps, and works in π mode at the resonant frequency of 202.5 MHz, with a phase angle of -90 degrees, and a maximum voltage per gap (E0L) of 55 kV. The detailed RF and thermal design was developed, followed by the manufacturing of a prototype, all being presented elsewhere. Several mechanical issues were noticed with the RF finger strips and tuners during the assembly of the prototype cavity. The manual tuner (to account for the manufacturing tolerances and the vacuum load) was machined to the final dimension to achieve the desired resonant frequency, according to the Vector Network Analyser (VNA) measurements. The measured quality factor was found to be much lower than expected, which required a redesign of some of the RF seals. The cavity was powered and conditioned in a relatively short time up to a nominal power, but severe multipacting was observed, initially only at low power, but later also at medium power levels, which required a creative approach to be fixed without a major cavity redesign.
Paper: TUPS047
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS047
About: Received: 03 Apr 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
TUPS051
Avoiding overcooled ion beams by exciting energy spread through electron cooling
1546
Ion accelerators use electron cooling to improve luminosity and beam lifetime. However, extremely low momentum spread in a cold beam weakens Landau damping, enabling the development of instabilities and potentially decreasing lifetime. To combat this, the NICA Booster electron cooling system allows to generate electron beams with oscillating energy to increase the momentum spread in ion beams. Here we describe the implementation of the energy oscillation technique and provide numerical calculations predicting the achievable momentum spread.
Paper: TUPS051
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS051
About: Received: 27 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
TUPS054
Optimization of a multichannel solid state plasma for laser wakefield acceleration with realistic laser parameters using a Bayesian algorithm
1552
Nanostructures based on carbon nanotube arrays are emerging as promising media for achieving ultra-high acceleration gradients in laser wakefield acceleration (LWFA). In this study, we design and optimize plasmas with hexagonal lattice structures, where the lattice parameters directly define the nanostructure's properties. Using WarpX, a state-of-the-art particle-in-cell (PIC) simulation framework, we conduct fully three-dimensional simulations to model the interaction between these advanced plasmas and laser pulses. To refine the lattice parameters, we apply Bayesian optimization through the Python library BoTorch, identifying optimal configurations for generating effective wakefields. These results are intended to guide preliminary simulations for future experiments at leading laser facilities, such as ELI and VEGA3, advancing the exploration of LWFA with nanostructured plasmas.
Paper: TUPS054
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS054
About: Received: 16 May 2025 — Revised: 31 May 2025 — Accepted: 02 Jun 2025 — Issue date: 10 Jul 2025
TUPS060
Electron cyclotron resonance accelerator for industrial radiation processing
1567
Industrial radiation processing is used on a wide variety of products, including medical devices for eradication of pathogens, food for preservation and safety, and plastics for material property modification. But millions of curies of Co-60 that are still used in some industrial sterilization facilities can pose a significant security risk in an act of radiological terrorism. Lower-cost electron beam systems with high beam-power efficiency and high reliability are needed to replace Co-60 based sterilization systems. A novel accelerator under development, electron Cyclotron Resonance Accelerator (eCRA) is described here. It is highly compact and efficient to produce high power electron beams and x-ray beams. The several attractive features of eCRA include: a compact robust room-temperature single-cell RF cavity as the accelerator structure; continuous ampere-level high current output without bunching; and a self-scanning accelerated energetic e-beam, obviating need for a separate beam scanner. Details of design and predicted performance will be described.
Paper: TUPS060
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS060
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
TUPS063
NLCTA and the X-band Test Area at SLAC
1574
The Next Linear Collider Test Accelerator (NLCTA) facility at SLAC National Accelerator Laboratory provides unique capabilities for conducting accelerator research and testing technology with accelerator applications, as well as beam time for experiments using the X-band Test Accelerator (XTA). Test areas in the facility support high power RF testing over a range of frequencies and operating temperatures, allowing for a broad range of ongoing research programs. Experiments include irradiation studies, high gradient accelerator testing, superconducting materials testing, detector testing, prototype development for medical applications like proton therapy for cancer treatment, and electron beam diagnostics using THz streaking. This variety in research topics takes advantage of the NLCTA's flexible infrastructure and wide range of in-house expertise. Facility capabilities and highlights from the active experimental program are presented here.
Paper: TUPS063
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS063
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
TUPS067
Development and operational performance of multi-alkali antimonide photocathodes
1578
Multi-alkali antimonide photocathodes, particularly potassium–cesium-antimonide, have gained prominence as photoemissive materials for electron sources in high-repetition-rate FEL applications due to their properties, such as low thermal emittance and high sensitivity in the green wavelength. To explore the potential of these materials in high-gradient RF guns, a collaborative effort was undertaken between DESY PITZ and INFN-LASA to develop and study multi-alkali photocathode materials. A batch of three KCsSb photocathodes and one NaKSb(Cs) photocathode was grown on molybdenum substrates using a sequential deposition method in the new preparation system at INFN LASA. These cathodes were successfully transferred and tested in the high-gradient RF gun at PITZ. Following the tests, a post-operational optical study was conducted on all the cathodes. Based on these findings, efforts are underway to optimize the fabrication recipes for KCsSb and NaKSb(Cs) photocathodes to achieve lower field emission and longer lifetimes. This contribution summarizes the experimental results of the production, operational performance, and post-usage analysis of the current batch of cathodes.
Paper: TUPS067
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS067
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
TUPS071
Theoretical models for CsTe thin film semiconductor photocathodes at high electromagnetic fields
1582
Understanding performance and limitation of CsTe photocathodes under high field gradients in a radio-frequency gun requires adequate theoretical models for material properties, photoemission and surface morphology. We are developing a suite of models based on Density Functional Theory (DFT), moment and Monte-Carlo (MC) photoemission models, and meso-scale material surface model informed by DFT and Molecular Dynamic (MD) simulations. Our DFT calculations provide detailed structural, elastic, electronic, optical, and transport properties of CsTe for photoemission applications. Temperature, density of states, and thin film optical effects have recently been incorporated in a moment-based photoemission model, while the high field effects for electron transport and emission are being modeled in the MC model. Our meso-scale surface model addresses surface morphology under high field stress and surface heating. Machine-learning technique has also been used to enhance the DFT and MD calculations for CsTe. This poster will present an overview of these theoretical models and their results with applications to the LANL CARIE project and other relevant experiments.
Paper: TUPS071
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS071
About: Received: 28 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
TUPS074
Packaged photocathodes for X-ray free electron lasers
1586
Alkali photocathodes are vital for generating high-performance electron beams in accelerator technologies, but their production remains challenging. Current in-house fabrication methods are complex, costly, and unreliable, limiting the potential of these materials for bright electron sources. Our innovative approach seeks to commodify photocathodes, offering a ready-to-use product for accelerator facilities and scientific institutions. We use a proprietary sputtering process with in-house-manufactured bulk targets, ensuring consistent quality and streamlined production. Unlike traditional vacuum suitcases, which are heavy and require active power, our photocathodes are stored in portable, palm-sized vacuum canisters that maintain vacuum without power. This design preserves their integrity during transport and handling, addressing their extreme sensitivity to air and moisture, which demands ultra-high vacuum protection. By delivering pre-fabricated, protected photocathodes, we eliminate the need for facilities to invest in specialized equipment, enabling broader adoption and reducing downtime. Our work paves the way for accessible, affordable, and readily available photocathodes.
Paper: TUPS074
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS074
About: Received: 31 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
TUPS089
Helical undulators assembled from magnetized ring sectors
1588
Undulators assembled from quasi-helices consisting of readily available magnetized ring rare-earth sectors are proposed. "Radially" magnetized sectors create a stronger field on the axis than longitudinally magnetized ones. The field value weakly depends on the number of sectors per undulator period. An experimentally studied prototype Halbach-type helical undulator of "radially" and longitudinally magnetized quasi-helices consisting of ring NdFeB sectors with a period of 2 cm and a comparatively large inner diameter of 8 mm provides a field of about 0.6 T on the axis. By reducing the inner diameter to 5 mm, it is possible to obtain a field twice as large. When assembling such an undulator, it is convenient, while maintaining the positions of all ring sectors, to use a division of the undulator not into quasi-helices, but into cylindrical sectors shifted along the axis and rotated relative to each other. Permanent undulators from ring sectors can provide a higher velocity of transverse electron oscillations than planar ones, and therefore seem promising for increasing the efficiency of FELs in various frequency ranges.
Paper: TUPS089
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS089
About: Received: 14 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
TUPS093
Permanent hybrid helical micro-undulators for FELs and inverse FELs
1595
High-field micro-undulators are one of the key elements in most compact Terahertz and X-ray FEL projects. In our works, helical undulators of several helices, each made of a single piece of rare-earth magnet, are proposed for this purpose. We demonstrated previously the possibility of high-precision manufacturing helices with centimeter periods using the Wire Electric Discharge Machining. In this paper, we will discuss an experimental prototype micro-undulator of two oppositely longitudinally magnetized NdFeB helices with a period of 6 mm and an inner hole diameter of 1 mm, creating a transverse field close to 1 T. The magnitude of the field and/or the inner diameter of the helices can be significantly increased by using hybrid systems with two longitudinally pre-magnetized rare-earth and two pre-unmagnetized steel helices. We are currently developing methods for manufacturing, assembling and measuring the parameters of such systems with periods of 6 and 3 mm and a field of 1 T and will demonstrate the corresponding results in the presentation.
Paper: TUPS093
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS093
About: Received: 14 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
TUPS111
Optical and laser systems for the AWAKE run 2C experiment
1604
In the AWAKE Run 2c experiment, two electron beams are injected into two separate rubidium (Rb) vapour sources. The first electron beam initiates the self-modulation of a proton bunch in the first vapour source, while the second electron beam serves as a witness beam for plasma wakefield acceleration with low energy spread in the second vapour source. This setup requires the precise spatio-temporal delivery of four laser beams: two deep UV beams that generate the electron beams with a relative timing jitter well below 100 fs, and two near-IR beams that ionize efficiently the Rb vapour sources. The UV pulses are generated by an established Yb laser system, capable of producing 400 uJ, 0.2-10 ps pulses at 257 nm with high reliability (<0.1% RMS energy fluctuation), and enables emittance optimization via spatial beam shaping. The same system is used for both electron sources, utilizing a partial reflector to split the beam and account for differing photocathode yields. For the Rb ionizing pulses, which are directed into the vapour sources in a counter-propagating geometry, the pulses from the AWAKE Ti:Sapphire laser system are transported using a series of vacuum relay telescopes.
Paper: TUPS111
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS111
About: Received: 15 Apr 2025 — Revised: 30 May 2025 — Accepted: 01 Jun 2025 — Issue date: 10 Jul 2025
TUPS120
The SPARTA project: toward a demonstrator facility for multistage plasma acceleration
1615
Plasma acceleration is a rapidly maturing technology, but is not yet ready for large-scale applications such as linear colliders. The SPARTA project aims to develop a near-term, medium-scale plasma-accelerator facility to enable new experiments in strong-field quantum electrodynamics (SFQED)—an application that requires solving two of the most important remaining challenges in plasma acceleration: reaching high energy by using multiple accelerating stages; and achieving high beam stability. We report on progress toward the three main objectives: demonstrating a nonlinear plasma lens for achromatic beam transport between stages; developing self-stabilization and instability suppression mechanisms; and developing a conceptual design for a multistage SFQED facility.
Paper: TUPS120
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS120
About: Received: 20 May 2025 — Revised: 01 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
TUPS128
Simulations of ion bombardment in thermionic cathode RF guns
1619
Thermionic cathodes are well known as a robust source of electrons for a wide range of accelerator applications. In the case of Barium Oxide cathodes the low work function that allows emission at modest temperatures is achieved through a surface coating. This coating can be damaged from both ion bombardment and, in the case of RF sources, electron bombardment. Lifetime models that predict the dynamics of these coatings are based on DC electron guns. Understanding the dynamics of ion bombardment in thermionic RF electron guns and under operational conditions is paramount to understanding cathode lifetime and optimizing performance. In this paper we simulate the generation of ions through impact ionization in the APS electron gun. We then compute the energy distribution of ions deposited on the cathode and effective ionization cross section as we vary operational conditions. These simulations are compared with analytical calculations based on first principles.
Paper: TUPS128
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS128
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
TUPS130
Compressed ultrashort pulse injector demonstrator
1623
High brightness electron beams have a wide range of applications ranging from accelerator-based light sources to ultrafast electron diffraction and microscopy. High accelerating gradient photoinjector is an important tool to generate brighter electron beams. However, high gradient photoinjector suffers issues from material breakdown due to extremely high surface electric fields. One possible path to simultaneously achieve high gradient and suppress breakdowns is to reduce the rf pulse duration fed into the photoinjector. Such an approach was recently demonstrated at the Argonne Wakefield Accelerator (AWA) facility where they commissioned an X-band photoinjector at 400 MV/m cathode field without significant breakdown rates. SLAC National Accelerator Laboratory recently developed rf pulse compression technology optimized for short pulses up to 500MW. We propose to develop an X-band photoinjector which can utilize these ultrashort rf pulses to produce surface fields at 500 MV/m or higher at the cathode. This presentation focuses on the design of the X-band photoinjector.
Paper: TUPS130
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS130
About: Received: 24 May 2025 — Revised: 31 May 2025 — Accepted: 01 Jun 2025 — Issue date: 10 Jul 2025
TUPS134
Improvement of electron beam properties for Few-TW LWFA conducted in a sub-mm gas cell filled with a helium-nitrogen mixture
1627
Developing a laser wakefield acceleration (LWFA) scheme by focusing few-TW laser pulses into a thin, dense gas target paves the way for generating high-average-current electron beams driven by a modern high-repetition-rate laser. Our previous study demonstrated that using a sub-mm nitrogen (N₂) gas cell facilitates the routine generation of 10-MeV-scale electron beams from few-TW LWFA with ionization-induced injection*. However, excessive ionization-induced defocusing of the pump laser pulse tends to occur in an N₂ target, motivating the use of a helium (He) – nitrogen (N₂) mixture as the gas target to mitigate pump pulse defocusing in few-TW LWFA**. In this study, the effect of nitrogen doping ratio ranging from 0.5% to 5% was investigated using 40-fs, 1-TW pulses with a 0.4-mm-long gas cell. We found that a manifest peak repeatedly appears around 10 MeV in the energy spectra with the 99.5% He - 0.5% N₂ gas mixture - a result never observed with the pure N₂ cell. Using the He-N₂ mixture also leads to a noticeable increase in the charge of high-energy electrons (>5 MeV) and a reduction in the pointing fluctuation of the output beams compared to the pure N₂ target.
Paper: TUPS134
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS134
About: Received: 27 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
WEXN1
Upgrade of KEK electron/positron injector LINAC using pulsed magnets and machine learning
1651
The KEK injector linac injects high-charge electron and positron beams into the high-energy-ring and low-energy-ring of SuperKEKB respectively. The linac also injects electron beams to the two light source rings, PF ring and PF-AR. We operate simultaneous top-up injections into the four rings by using many pulsed magnets. We have been upgrading the linac to attain the higher-quality beam injections for the SuperKEKB rings. In the summer of 2023, large-aperture quadrupole pulsed magnets have been newly installed upstream of the linac and driven by large-current pulse power supplies at markedly high electric efficiency. These new magnets bring the pulse-by-pulse optics changing to provide the high-quality beams. In order to cope with the complex beam injections to the four rings, we have introduced the automatic adjustment system by using machine-learning. The system surpasses human skill in beam adjustment and has resulted in significant increases in the amount of beam charge and beam transmission. We will report on the results of these upgrades.
Paper: WEXN1
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEXN1
About: Received: 28 May 2025 — Revised: 31 May 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
WEAN1
Measurement techniques using the electron beam profile scanner at the Fermilab Main Injector
1670
This work presents techniques for non-invasive transverse profile measurements of high-intensity proton beams using an Electron Beam Profile Scanner (EBPS). The EBPS utilizes low-energy electrons as a probe to analyze the transverse size of proton beams, allowing for potential analysis on a single-bunch basis. Recent upgrades to the Fermilab Main Injector have enhanced beam power on target to 1 MW, with future developments targeting 2 MW. The higher beam power has increased the demand for non-invasive diagnostics, as invasive methods can disrupt operations. The techniques presented include 1) the slow scan technique, which serves as a proof of concept for the probe beam, 2) the one-shot scan technique for measuring horizontal beam profiles, and 3) the raster scan technique for analyzing horizontal beam profiles as a function of the longitudinal distribution of the beam. The profiles obtained will be crucial for studying and understanding instabilities in high-power, high-intensity proton beams. This will contribute to optimizing the operation of high-power proton accelerators by minimizing beam loss, activation, and damage to both the diagnostics and the accelerator components.
Paper: WEAN1
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEAN1
About: Received: 01 Jun 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
WEYN1
Ultrafast visualization of quasi-three-dimensional electric field of relativistic electron beam
1687
EM (electromagnetic) field around a relativistically ac-celerated charged particle is known to be squeezed longi-tudinally. This behavior is called the Lorentz contraction, and no inconsistent phenomena have been found. How-ever, an experiment has not directly confirmed the Lo-rentz contraction of the EM field. The first direct observa-tion of the Lorentz contraction of the EM field was recent-ly performed using an electron linac at the University of Osaka[*]. The electric (Coulomb) field around a sub-picosecond electron beam with an energy of 35 MeV was measured by an electro-optic (EO) sampling method. A single-shot electric field measurement system was devel-oped using EO sampling and an echelon mirror. A modu-lated laser light due to the Pockels effect was decoded into a spatio-temporal image of the electric field, and the Lo-rentz contraction was directly confirmed. This ultrafast measurement technique can help longitudinal diagnostics of a charged particle beam. This presentation will report ultrafast visualization of quasi-three-dimensional (trans-verse and longitudinal) electric fields of a relativistic elec-tron beam and their evolutions.
Paper: WEYN1
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEYN1
About: Received: 26 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 10 Jul 2025
WEPB013
Thermal analysis for the fundamental power coupler of the 197 MHz crab cavity for EIC
1745
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: 10 Jul 2025
WEPB014
Sensitivity analysis of the 197 MHz prototype crab cavity for EIC
1749
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: 10 Jul 2025
WEPB020
Highly stable pulse operation of 476 MHz solid-state amplifiers with a precision of 0.01 degrees at SACLA
1768
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: 10 Jul 2025
WEPB023
Transitional solution of solid-state power amplifier at NSRRC
1777
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: 10 Jul 2025
WEPB026
Magnetic design of the cSTART magnets
1788
The KIT project cSTART (compact STorage ring for Accelerator Research and Technology) aims to store ultra-short electron bunches in a very-large-acceptance compact storage ring. The magnetic lattice of the storage ring is laid out for a variety of beam optics, including ultra-low positive and negative alpha as well as isochronous optics. These put high demands on the magnet quality and alignment. The spatial constraints for the storage ring impose further challenges on the magnet design. In this contribution, we give an overview of both the challenges and solutions for the cSTART storage ring magnet design.
Paper: WEPB026
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB026
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
WEPB028
Kicker magnets for fast-switching elliptical polarized undulators beamline of the TPS
1796
The variation of polarized light is a critical characteristic of synchrotron radiation sources. To accommodate diverse user needs and enable helicity switching, a soft X-ray beamline has been designed to alternate the helicity of polarized undulator radiation. This is achieved by switching between two undulators, configured to provide right and left circularly polarized radiation, respectively. To separate and select these two circularly polarized photon beams, six kicker magnets are installed in the straight section. This paper details the design considerations, fabrication processes, and field measurement results of these kicker magnets, emphasizing their role in achieving seamless helicity switching and supporting the beamline’s functionality for cohabitation of multiple users.
Paper: WEPB028
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB028
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
WEPB030
Efficient nonlinear simulations of the fast corrector magnets for PETRA IV
1803
Fast orbit feedback systems are an important component in fourth-generation synchrotron radiation sources such as PETRA IV at DESY in Hamburg, Germany. These control systems are designed to stabilize the particle orbit, i.e., to correct deviations from the design orbit due to various disturbances. To that end, such a system employs fast orbit corrector magnets, which must be powered at frequencies up to the kilohertz range. This leads to significant eddy current effects that must be predicted via finite element simulations. Therefore, extensive simulation studies have already been conducted. These simulations did not, however, consider the magnetization curve’s nonlinearity since doing so requires prohibitive computational effort when using commercial software. Hence, we have constructed a dedicated method, based on a combination of the harmonic balance finite element method and homogenization schemes, to enable nonlinear simulations. This contribution outlines the general idea and application of our method to the corrector magnets of PETRA IV and presents the most important findings regarding the impact of the nonlinear magnetization curve on the magnet’s performance.
Paper: WEPB030
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB030
About: Received: 05 May 2025 — Revised: 30 May 2025 — Accepted: 30 May 2025 — Issue date: 10 Jul 2025
WEPB038
Magnetic circuit design and consideration for HTSW using 12mm HTS tape
1822
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: 10 Jul 2025
WEPB045
Performance Analysis and Stability Enhancement Plan for the Sextupole Magnet Power Supply in Storage Ring
1836
Since its official operation in 2016, the Taiwan Photon Source (TPS) has been dedicated to providing a stable and high-quality synchrotron radiation light source. The TPS storage ring is divided into 24 sections, each equipped with 7 sextupole power supply units, totaling 168 units. These power supplies are responsible for delivering precise and stable current to drive the sextupole magnets. This paper focuses on evaluating the long-term operational stability of the sextupole power supply system since its commissioning and proposes a targeted upgrade strategy to address potential reliability issues. To enhance overall system stability and yield, and to effectively reduce the frequency of beam trips caused by power supply faults, an upgrade plan involving the adoption of ultra-high-precision power supplies has been proposed. In addition, the removed high-precision power supplies will be repurposed as spares to improve system redundancy and fault response capability. The upgrade project is scheduled for full implementation by 2028. A pilot installation has already been completed in Cell 22, and successful electron beam storage was achieved at the end of 2024. Preliminary assessments suggest that, upon completion, the upgrade will reduce the number of beam trip events by approximately 2 to 3 times per year and decrease the total annual downtime by around 4 to 6 hours, thereby significantly improving the operational reliability of the TPS storage ring and the quality of service provided to users.
Paper: WEPB045
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB045
About: Received: 22 Apr 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 10 Jul 2025
WEPB048
Magnetic measurement of a decommissioned insertion device at the Canadian Light Source
1843
The Canadian Light Source has decommissioned three insertion devices in recent years, replacing each with upgraded devices. The decommissioned devices are planar undulators that have seen approximately 15 years of operation in a 2.9 GeV storage ring, two being out-of-vacuum devices with 45 mm and 185 mm periods and one being an in-vacuum 20 mm device. In this paper we present magnetic measurements of the decommissioned 185 mm device (U185) with comparisons against the original measurements from before it was put into service.
Paper: WEPB048
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB048
About: Received: 24 May 2025 — Revised: 30 May 2025 — Accepted: 31 May 2025 — Issue date: 10 Jul 2025
WEPB056
Status of VPU development for PAL-XFEL
1865
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: 10 Jul 2025
WEPB057
Field measurements of a short period helical superconducting undulator
1868
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: 10 Jul 2025
WEPB059
Testing and characterization of surface treatment techniques for enhancing the HV performance of kickers
1872
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: 10 Jul 2025
WEPB063
Study of a fast kicker magnet for beam scanning in VHEE therapy
1887
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: 10 Jul 2025
WEPB065
Development of compact ultra-high power pulsed power supply
1893
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: 10 Jul 2025
WEPB084
Design of normal conducting quadrupoles for the spin rotator section in the EIC electron storage ring
1915
The interaction region IR6 in the Electron Storage Ring of the planned Electron Ion Collider facility at Brookhaven National Laboratory includes a section to rotate the electron spin into or out of the longitudinal direction. This section consists of superconducting solenoids, and normal conducting dipoles and quadrupoles. The geometry and field gradient requirements of the quadrupoles pose a challenge in their design with regards to yoke saturation and thereby field quality. Electromagnetic design of one such quadrupole is the focus of discussion in this article. The design process involves optimization of the pole tip, yoke and conductor size using two and three-dimensional finite element method tools.
Paper: WEPB084
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB084
About: Received: 22 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
WEPM019
Data driven methods to recognize patterns in EIC weak-strong simulation
1996
Beam-Beam simulations are currently being studied in preparation for future EIC experiments to study beam-beam effects and, in turn, maximize luminosity. Weak-strong methods are studied for single-particle dynamics during collision. 1 million macro-particles for 1 million turns are typically tracked, corresponding to only 10 seconds in the EIC. The goal of this study is to predict beam properties over the scale of hours. A potential solution focuses on using data-driven methods such as machine learning methods to analyze and extend the insights of the beam properties such as long-term nonlinear effects. This would aid in long-term predictions where results would be more efficiently acquired than a typical tracking simulation. Some limitations such as inaccurate predictions and spatial complexity are also discussed. These methods can then be applied to strong-strong simulations in the future studies.
Paper: WEPM019
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM019
About: Received: 28 May 2025 — Revised: 01 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 10 Jul 2025
WEPM026
Study of an anomalous beam profile in the Compact ERL’s injector at KEK
2012
The cERL injector objective is to produce and deliver a high-quality electron beam to the recirculation loop. However, a recent observation of an anomalous "triangle beam" profile just after the first solenoid presents significant challenges. This distorted beam profile can lead to inaccurate parameter measurements, reduced focusing and collimation efficiency, and increased sensitivity to injector errors. This study investigates potential causes, including hexapole field components, misalignment, nonlinearity of air-core steering, and beam kick at cathode. Machine learning techniques are employed to analyze experimental data and simulation results to identify the primary factors. Based on these findings, potential solutions to mitigate the "triangle beam" issue and optimize injector performance are proposed.
Paper: WEPM026
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM026
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 10 Jul 2025
WEPM030
Beam optics simulations of achromatic section of Delhi Light Source
2024
The Delhi Light Source is an upcoming user facility for coherent THz radiation and electron beam. Electron beam of energy upto 8 MeV generated from a RF photo-cathode gun will be used for coherent THz generation from a planer undulator. The beam after passing through the undulator field will be separated from the THz and THz line by a $60^{o}$ achromatic section and delivered to electron experimental area. Simulation studies has been performed to achieve achromatic condition and acceptable beam size at the electron experimental area for the case of electron transmission through non-trivial undulator field. However for the case of open gap undulator (no THz generation), the study shows that the same design gives a limited control on the overall beam size at the electron experimental area. To overcome this the extended quadrupole correction (EQC) coils of the undulator can be used as a suitable focussing element to achieve required beam size control in addition to the achromatic condition. The paper presents the simulation studies of the achromatic section for both with and without(open gap) undulator field.
Paper: WEPM030
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM030
About: Received: 20 May 2025 — Revised: 30 May 2025 — Accepted: 01 Jun 2025 — Issue date: 10 Jul 2025
WEPM077
Resistive wall impedance calculations and effects of NEG coated insertion device vacuum pipes for the PF-HLS ring
2149
I show analytical expressions of the longitudinal and transverse impedances of a two-layered circular pipe and their practical expressions at high frequencies derived by using asymptotic expansions of the Bessel functions. These expressions are applied to resistive-wall impedance calculations of NEG-coated insertion-device(ID) pipes for the PF-HLS ring*, which is proposed as a 2.5/5.0 GeV energy switchable ring and can simultaneously provide synchrotron light pulses emitted by electron bunches stored in the ring and by extremely short electron bunches (50 fs in length) injected from the superconducting linac. Both real and imaginary parts of the impedances rise up in high frequency regions depending on the NEG coating thickness. The heating powers of the ID pipes are calculated from the real parts of the longitudinal impedances for the stored electron beam and for the short electron bunches injected from the superconducting linac. The kick factors and the coherent betatron tune shifts due to the ID pipes are calculated from the imaginary parts of the transverse impedances for the stored electron beam. These dependences on the NEG-coating thickness are shown in this presentation.
Paper: WEPM077
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM077
About: Received: 27 May 2025 — Revised: 30 May 2025 — Accepted: 30 May 2025 — Issue date: 10 Jul 2025
WEPM080
Impact of the cSTART impedance on beam dynamics
2160
The combination of a compact storage ring and a laser-plasma accelerator (LPA) can serve as the basis for future compact light sources. One challenge is the large momentum spread (about 2%) of the electron beams delivered by the LPA. To overcome this challenge, a very large acceptance compact storage ring (VLA-cSR) was designed as part of the compact STorage ring for Accelerator Research and Technology (cSTART) project, which will be realized at the Karlsruhe Institute of Technology (KIT, Germany). Initially, the Ferninfrarot Linac- Und Test-Experiment (FLUTE), a versatile source of ultra-short bunches, will serve as an injector for the VLA-cSR to benchmark and emulate LPA-like beams. In a second stage, a laser-plasma accelerator will be used as an injector. The large-momentum spread bunches in non-equilibrium and with charges from 1 pC to 1 nC and lengths from few fs to few ps pose challenges for the beam dynamics simulations. An understanding of the ultra-short bunch dynamics also requires an impedance model up to high frequencies. Here, we present first results on the impact of the machine impedance to the beam dynamics.
Paper: WEPM080
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM080
About: Received: 26 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 10 Jul 2025
WEPM100
Parametric optics for FUDU lattices with strongly focusing undulators
2211
In low-energy FEL beamlines, like SXFEL-SBP at the Shanghai Synchrotron Radiation Facility and FLASH1 and FLASH2 at DESY, SASE undulators with perfectly reasonable strength may dynamically affect the optics of the Focusing-Undulator-Defocusing-Undulator (FUDU) cells, pre-matched for a given fixed set of undulator parameters, so violently that a dynamical re-adjustment of the FUDU quadrupoles becomes mandatory. Here we refine and generalize a result reported at the FEL conference 2024. Our almost-analytical result allows implementation in the control system, and is valid for fairly general symplectic coupling-free perturbing matrices. In an approximative sense it includes undulators changing along the beamline and even missing undulators in given cells.
Paper: WEPM100
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM100
About: Received: 28 May 2025 — Revised: 29 May 2025 — Accepted: 01 Jun 2025 — Issue date: 10 Jul 2025
WEPS010
Photoinjector beam halo formation due to a secondary picosecond time-delayed laser pulse
2260
Beam halo formation is a significant challenge for high-intensity accelerators, as it can lead to performance degradation and radiation safety risks. This study investigates the formation and mitigation of beam halos caused by a picosecond time-delayed laser pulse, which generates a secondary electron bunch in the same RF bucket as the main bunch. The energy difference between the two bunches creates a defocusing effect, leading to the halo generation. Experimental validation of RF-Track simulations was conducted at the AWAKE Run 2c test injector (ARTI). The research outlines methods for identifying, analyzing, and mitigating laser-driven beam halo formation, contributing to more effective control of beam halos in accelerator operations.
Paper: WEPS010
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS010
About: Received: 16 May 2025 — Revised: 31 May 2025 — Accepted: 02 Jun 2025 — Issue date: 10 Jul 2025
WEPS015
Simulation of electron beam transport through the coherent electron cooling amplification section using real number of electrons
2271
Coherent electron cooling plays an important role in the Electron Ion Collider (EIC) by providing a fast cooling rate at collision energy to counter the emittance growth driven by intrabeam scattering effects. In this paper, we report on the high-fidelity simulation of the electron beam transport through the amplification section of the cooling channel. We will show the amplification of the initial modulation in the electron beam from the protons and present the study of collective effects such as the space-charge and CSR effects on the process of modulation amplification.
Paper: WEPS015
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS015
About: Received: 20 May 2025 — Revised: 31 May 2025 — Accepted: 31 May 2025 — Issue date: 10 Jul 2025
WEPS023
Study for limiting factors in transverse wiggler-based arbitrary correlation generation
2294
Recently proposed transverse wiggler is an intriguing tool for imparting designed correlations in phase space. While several simulations have demonstrated its feasibility, the method using the transverse wiggler has several concerns need to be addressed. Beam evolution along the wiggler can introduce errors in the designed correlation. Wiggler fields have strong vertical position dependence, which can introduce unwanted horizontal and vertical couplings. The transverse wiggler generates both horizontal and vertical sinusoidal fields, which can significantly degrade the beam quality. Additionally, its applicability to heavy particles remains uncertain. We will present results from a preliminary study aimed at addressing these concerns.
Paper: WEPS023
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS023
About: Received: 28 May 2025 — Revised: 30 May 2025 — Accepted: 01 Jun 2025 — Issue date: 10 Jul 2025
WEPS025
Design, manufacturing and validation of fast-ramping alpha magnet for interleaving operation at ANL APS
2298
RadiaBeam has designed and manufactured a fast-ramping alpha magnet (FRAM) that is developed for interleaved operation at the Advanced Photon Source (APS) at Argonne National Laboratory. This interleaving operation requires the alpha magnet to stably complete a 5 s long cycle with a 100 ms ramp-up, 1s nominal field output and a 100 ms ramp-down. A laminated yoke is used to minimize eddy currents, ensure fast field response times and reduce core-loss during operation. The magnet has been measured by a Hall probe at Radiabeam and at Argonne, demonstrating 2.75 T/m maximum field gradi-ent within a 10 cm x 14 cm good field region in both DC and pulse modes.
Paper: WEPS025
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS025
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
WEPS042
Benchmarking Intrabeam Scattering with RF-Track
2333
Intra-beam scattering (IBS) has recently gained significant interest in the community of free electron lasers (FELs), as it is believed to produce an increment in the sliced energy spread (SES), which is detrimental to FEL performance. To control and contain this phenomenon, it is important to include IBS in the design phase of an FEL through appropriate numerical simulation. Most existing codes that simulate IBS were developed for long-term tracking in circular lattices, assuming Gaussian bunches. Unfortunately, this assumption doesn’t capture the rapid bunch evolution of electron bunches in photoinjectors. To address this limitation, the tracking code RF-Track has recently been updated to include IBS, using a novel hybrid-kinetic Monte Carlo method. This paper presents benchmarks performed to verify the implementation. The predicted SES increment in the beam due to IBS using RF-Track has been compared against a kinetic approach used in a different tracking code and, secondly, against a semi-analytical model. The results showed a good agreement, setting RF-Track as a tool to understand and control the SES growth in photoinjectors and, in particular, in FEL.
Paper: WEPS042
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS042
About: Received: 04 Apr 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
WEPS043
Achieving diverse beam modes with modelling and optimisation for the versatile SRF photoelectron gun at SEALab
2337
The SEALab facility in Berlin is home to an R\&D superconducting radio-frequency (SRF)photoinjector setup and beamline. Designed to support multiple varied applications - ranging from Energy Recovery Linac (ERL) to Ultrafast Electron Diffraction (UED) and Electron-Beam Water Treatment (EBWT) - SEALab requires flexible, high-precision tuning to support these diverse beam modes. These applications span over three orders of magnitude in bunch charge, emittance, and current, alongside sub-picosecond pulse lengths. This makes injector setup and tuning a significant challenge. With the world's first beam achieved at SEALab from a Na-K-Sb cathode in our SRF gun, a suite of beam dynamics models has been developed to support understanding of the beam behaviours in the gun, where no observations are possible, and operation of the commissioning process. This is comprised of a first-order analytical model, particle-in-cell (PIC) ASTRA simulations, and a machine-learning surrogate model trained for current commissioning operation ranges. These models are coupled with a Multi-Objective Bayesian Optimisation (MOBO) algorithm to enable rapid tuning across multiple beam modes. This combination of surrogate modelling and optimisation algorithm reduces optimisation timescales from hundreds of hours to minutes, allowing near-real-time tuning for the accelerator. This work presents the modelling framework, its validation, and its application to SEALab's many-mode optimisation challenges.
Paper: WEPS043
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS043
About: Received: 28 May 2025 — Revised: 01 Jun 2025 — Accepted: 01 Jun 2025 — Issue date: 10 Jul 2025
WEPS050
Electron cloud mitigation techniques for the FCC-ee
2354
The Future Circular Collider (FCC)-ee is a planned electron-positron collider under development. The future collider would be built in an about 91 km ring-shaped underground tunnel located beneath the French departments of Haute-Savoie and Ain, and the Swiss canton of Geneva. The FCC-ee may face challenges from electron cloud (e-cloud). The strongest effects are foreseen for the Z configuration, due to the highest number of bunches, which corresponds to the smallest bunch spacing, which is a key parameter for the e-cloud formation process. A high electron density in the beam pipe could limit the accelerator’s achievable performance through various mechanisms, such as transverse instabilities, transverse emittance growth, particle losses, vacuum degradation and additional heat loads on the inner surface of the vacuum chambers. In the design phase, the objective is to suppress the e-cloud effects in the FCC-ee. Therefore, effective e-cloud mitigation techniques, to avoid the e-cloud avalanche multiplication and its deleterious effects, are discussed in the paper.
Paper: WEPS050
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS050
About: Received: 27 May 2025 — Revised: 03 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
WEPS051
Filling pattern with non-uniform bunch spacing to mitigate e-cloud for the FCC-ee
2358
The Future Circular Collider (FCC) study is developing designs for higher performance particle colliders that could follow on from the Large Hadron Collider once it reaches the end of its high-luminosity phase. In particular, the FCC-ee is a proposed electron-positron collider that may face challenges from the electron cloud (e-cloud). Specifically, the Z configuration foresees the highest number of bunches. Consequently, this configuration could suffer more form the deleterious effects of the e-cloud, such as transverse instabilities, transverse emittance growth, particle losses, vacuum degradation and additional heat loads on the inner surface of the vacuum chambers. The e-cloud effects have been observed in several circular accelerators all over the world and it is much more commonly in those operated with positively charged particles. Presently, it is among the major performance limitations for high energy collider. Therefore, the study of e-cloud mitigation techniques is crucial during the accelerator's design stage to suppress the e-cloud avalanche multiplication. This paper analyses the use of non-uniform bunch spacing patterns as a potential e-cloud mitigation strategy.
Paper: WEPS051
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS051
About: Received: 27 May 2025 — Revised: 30 May 2025 — Accepted: 01 Jun 2025 — Issue date: 10 Jul 2025
WEPS052
Investigating electron cloud formation in FCC-ee nested magnet designs
2362
The Future Circular Collider is an ambitious international proposal for a next-generation particle accelerator complex, building upon the successes of CERN’s Large Hadron Collider. Specifically, the FCC-ee is a future circular lepton collider. The baseline design for the FCC-ee features four modes of operation, with beam energies ranging from 45.6 GeV to 182.5 GeV. Electron cloud (e-cloud) could be a concern for the FCC-ee due to the high number of bunches foreseen for the Z configuration, which results in small bunch spacing. The bunch spacing is a key parameter for the e-cloud formation process, as very small bunch spacing could lead to the avalanche multiplication and its deleterious effects. Moreover, electron trajectories are strongly influenced by externally applied magnetic fields, which could trap electrons and alter their survival time inside the vacuum chamber. The concept of nested magnets, which involves overlapping dipole fields with quadrupolar and/or sextupolar gradients, is under investigation. This approach aims to increase the dipole filling factor and reduce the synchrotron radiation. In this paper, the nested magnets are studied from the e-cloud point of view.
Paper: WEPS052
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS052
About: Received: 27 May 2025 — Revised: 03 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
WEPS067
Development of high-power RF components for an X-band transverse deflector system at SACLA
2385
We have been developing an X-band transverse deflector system (XB-TDS) with sub-fs time resolution, which will be installed after the undulator sections at SACLA. A sub-fs XFEL pulse is desirable for user experiments such as the measurements of structural disordering in an XFEL interaction with a matter, as the degree of damage depends on the pulse duration. The demand for a shorter and shorter XFEL pulse is increasing. The SACLA’s XFEL pulse duration is 6 fs at FWHM. In order to achieve a shorter XFEL pulse duration and to satisfy users’ needs, a diagnostic system of the longitudinal bunch distribution is essential. We adopt an X-band frequency to efficiently deflect an 8 GeV electron beam. We feed 20 MW to the pulse compressor, and the peak power is increased to around 100 MW, which is divided into four cavities, generating HEM11 horizontal mode. We utilize a dipole magnet before the beam dump to measure the energy-time distribution.The current status is to manufacture high-power RF components such as deflector cavity, pulse compressor, and dummy load. In this presentation, we will show the design, manufacturing method, and commissioning status of these components.
Paper: WEPS067
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS067
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
WEPS091
Intrabeam scattering in SRF "SKIF" storage ring
2408
SKIF (Russian acronym for Siberian Circular Photon Source) – is a new fourth generation synchrotron light source under construction in Novosibirsk, Russian Federation. One of the most important characteristics of the synchrotron radiation source SRF "SKIF", which in turn determines its brightness, is the ultra-low emittance of the electron beam, which depends on the operating regime and parameters of the storage ring: the intensity of the electron beam, the insertion devices parameters, the coupling coefficient of linear betatron oscillations, the elongation of the bunches, etc. Intrabeam scattering (IBS) is a collective effect that causes bunch volume inflation and brightness decrease for high intensity beams. Described in this work are the results of study of IBS impact on beam emittance, energy spread, Touschek lifetime and geometrical brightness for different operating regimes of the SRF “SKIF” storage ring.
Paper: WEPS091
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS091
About: Received: 29 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
WEPS102
Reconstructing wake functions using Haissinski distributions from multiple bunch charges
2419
Accurate knowledge of wake functions is crucial in accelerator physics, serving as the cornerstone for understanding intra-bunch interactions and for controlling or mitigating instabilities that limit accelerator performance. Haissinski distributions, which describe the steady-state longitudinal bunch density, are intrinsically determined by the wake function experienced by the bunch. While these distributions are typically computed from a given wake function, we investigate the inverse problem: extracting the wake function directly from measured Haissinski distributions. In this theoretical work, we introduce a novel method to reconstruct wake functions by utilizing Haissinski distributions obtained at multiple bunch charges. By combining these profiles into an overdetermined system, we address challenges posed by the inverse problem, which is sensitive to noise and discretization errors. Here, our preliminary results suggest that the use of regularization techniques may help achieve more stable reconstructions of the wake function.
Paper: WEPS102
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS102
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
THAD2
A method for measuring energy gain with variable plasma length at AWAKE
2469
The Advanced Wakefield (AWAKE) experiment is a proof-of-principle accelerator facility at CERN (Geneva, Switzerland). Proton bunches from the CERN Super Proton Synchrotron are used to drive wakefields in 10 metres of laser-ionised rubidium plasma, over which externally injected 19 MeV electrons are accelerated. Run 1 of AWAKE successfully demonstrated the self-modulation of the long proton bunch, and the acceleration of electrons to 2 GeV. Upgrades to the rubidium vapour source during Run 2 have enabled the use of a plasma density step, and variation of the plasma length through the insertion of foils along the source to dump the laser pulse. When placed suitably within the development of self-modulation, the density step is expected to preserve the wakefield amplitude, and therefore accelerating gradient, over longer distances than with uniform plasma. This work presents the first measurements of electron acceleration with a density step, studied as a function of the plasma length.
Paper: THAD2
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THAD2
About: Received: 08 Apr 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
THAN1
Assessing the origin of the LHC beam halo
2473
Measurements of the transverse beam-halo population at large amplitudes in the Large Hadron Collider (LHC) provide crucial insights into the stored beam energy near the LHC collimators. These particles do not contribute significantly to the luminosity but their loss could impose limitations on accelerator performance through sudden loss spikes or even collimator damage in case of fast beam failures. A thorough understanding of the beam halo formation, along with the physical mechanisms driving its behaviour and evolution throughout the final stage of the LHC injection chain and during the acceleration cycle, is essential to define appropriate mitigation strategies to ensure reliable operation in view of High Luminosity LHC beam parameters. In this study, we explore potential origins of the transverse beam halo by examining experimentally multiple contributing factors to halo formation, including electron cloud effects, beam injection dynamics from the Super Proton Synchrotron (SPS), and the energy ramping process within the LHC.
Paper: THAN1
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THAN1
About: Received: 27 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
THYN1
Deceleration of ion beams - Related challenges and opportunities
2487
The GSI facilities of CRYRING and HiTRAP are used for decelerating ion beams to low energies. This deceleration phase is preceded by the generation and acceleration of those ions. CRYRING and HiTRAP operate at the junction between accelerator science and atomic physics. The scientfic motivation, the operation principle, the state of the art and future outlooks are presented.
Paper: THYN1
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THYN1
About: Received: 30 May 2025 — Revised: 03 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
THBD1
Development of an RFSoC-based low-level RF controller for an electron linac
2491
We are developing a low-level RF (LLRF) controller based on RF System on Chip (RFSoC) for an electron linac. The AMD Zynq RFSoC was employed for this controller, which has a large-scale high-speed FPGA together with high-speed ADCs and DACs (8 channels each). The RFSoC also has an application CPU for Linux and a real-time CPU for time-critical tasks, capable of a 1 kHz repetition rate. A general-purpose pizza-box module with an RFSoC was designed and manufactured, and firmware for LLRF control was developed. This LLRF module will be first utilized for an X-band (11.424 GHz) transverse deflector system* for SACLA. A pulsed X-band RF signal is generated by upconverting a 476 MHz IF signal from the DAC and RF signals from the X-band high-power components are converted to 476 MHz IF signals and digitized by ADCs. The IF signal is converted to a baseband IQ signal and the phase and amplitude are obtained. Since the latency of ADC, DAC, and FPGA is as short as several 100 ns, the intra-pulse feedback control is anticipated to stabilize the phase and amplitude of the acceleration RF field. This presentation will give the design and basic performance of the LLRF controller.
Paper: THBD1
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THBD1
About: Received: 28 May 2025 — Revised: 29 May 2025 — Accepted: 30 May 2025 — Issue date: 10 Jul 2025
THPB012
Development and laboratory validation of a precise alignment setup for electron beam-based THz radiation generation at European XFEL
2523
We present the development and laboratory testing of a precise alignment setup for the STERN experimental area at the European XFEL, aimed at exploring beam-based THz radiation generation methods using Cherenkov waveguides. The setup employs an alignment laser to simulate the electron beam trajectory, enabling the accurate positioning of critical components, such as a copper block housing dielectric waveguides. The alignment process involves scintillator screens placed before and after the vacuum chamber to measure the electron beam trajectory, with the alignment laser subsequently adjusted to replicate this path. The experimental validation focused on the reproducibility of alignment under simulated operational conditions, testing the positioning and movement of mirrors, and ensuring the stability of the alignment system for the critical components.
Paper: THPB012
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPB012
About: Received: 28 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
THPB026
Utility design of the 3 GeV electron storage ring for Siam Photon Source II
2561
The Siam Photon Source II (SPS-II) is a new synchrotron light source currently under development in Thailand. Its 3 GeV electron storage ring features a lattice composed of 14 Double Triple Bend Achromat (DTBA) cells, with a total circumference of 327.6 meters. To ensure beam stability and operational reliability, a comprehensive suite of utility systems is required. The design incorporates critical infrastructure, including the electrical power system, deionized (DI) water system, air conditioning system, and compressed air system. These utilities provide essential support to both accelerator and beamline subsystems, such as magnets and power supplies, RF cavities and power supplies, vacuum chambers, insertion devices, front-end components, and experimental beamlines. This paper focuses on design considerations for the stability of the electrical power systems and the temperature regulation of the DI water and air conditioning systems. The electrical power demands and cooling loads are estimated based on the specific operational requirements of each accelerator subsystem.
Paper: THPB026
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPB026
About: Received: 28 May 2025 — Revised: 31 May 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
THPB027
Novel photoinjector laser providing advanced pulse shaping for FLASH and EuXFEL
2564
We recently commissioned the Next GenerAtion Photocathode Laser system (NEPAL) in Hamburg’s XFEL facilities (FLASH and EuXFEL) and at DESY’s Photoinjector Test Facility (PITZ). The system delivers deep UV pulse trains up to 1 ms long at repetition rates as high as 4.5 MHz, with temporal and spatial shaping capabilities and individual amplitude control for bunch charge manipulation. The shaping features enable the generation of exceptionally low emittance electron beams, essential for extending the EuXFEL X-ray photon energy beyond 25 keV and for future high duty cycle upgrades. Temporal shaping is achieved through a high-resolution spatial light modulator in the near-infrared driver laser, allowing precise spectral amplitude and phase control of UV pulses. We will present advanced control schemes that pre-compensate for laser nonlinearities and initial experimental results at EuXFEL. We generated UV flat-top pulse profiles with durations ranging from 10ps to 20ps and successfully transferred them onto the electron beam. This achievement represents a significant step toward emittance optimization at EuXFEL and will expand the facility's operational energy range in the near future.
Paper: THPB027
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPB027
About: Received: 10 Jun 2025 — Revised: 14 Jun 2025 — Accepted: 14 Jun 2025 — Issue date: 10 Jul 2025
THPB030
CFD thermal studies of the air inside the storage ring tunnel of the ALBA synchrotron light source for the 3rd and 4th generation designs
2576
The ALBA Synchrotron is currently designing its new version to become a 4th generation particle accelerator. In this new scenario, ALBA would produce a brighter and more coherent photon beam. As a result, ALBA would provide capabilities hitherto inaccessible in terms of resolution, detection levels and understanding of chemical and electromagnetic properties. In this context, the thermal and geometric conditions inside the tunnel will be modified, specifically the Storage Ring. The Booster Ring, Transfer Lines, Air Conditioning System and the tunnel itself will not be modified. The prediction of the thermal behaviour of the air inside the tunnel for the 4th generation is essential, considering the influence of the stability of the air temperature on the stability of the electron beam orbit. The present work assesses Computational Fluid Dynamics (CFD) studies of the air inside both the current and the 4th generation ALBA tunnel. Comparative studies of the temperature distribution in the air are performed and proposals for the optimization of the air conditioning system are presented. The studies are based on the FLUENT software of ANSYS WORKBENCH.
Paper: THPB030
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPB030
About: Received: 22 May 2025 — Revised: 03 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
THPB043
PM magnet development status for BESSYII+
2598
Permanent-Magnet (PM) magnets combine up to zero power consumption with highly stable magnet operation without ripple and cooling vibration effects for more energy-efficient and stable accelerator operation. As part of the upgrade program BESSYII+, we will install the B2PT dipole triplet as the first PM-based accelerator magnet. It concludes the BESSYII transfer line, transporting the electron beam from the booster to the storage ring and bends the beam into the injection septum of the BESSYII storage ring. The new B2PT is planned with three PM hybrid dipole units of 300 mm length each to substitute the present power-hungry 1-m long electromagnet. The triplet produces a stable magnetic field that can be trimmed during operation by electro-correctors in the outer magnets. The permanent magnetic field reduces injection noise into the storage ring and shrinks the total power consumption by almost 30 kW. This paper reviews simulated beam bending optimization of the B2PT PM triplet and its assembly process opening up to PM magnet development also required for the preparation of the future 4th-gen low-emittance source BESSYIII.
Paper: THPB043
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPB043
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
THPB061
MEDSI 2025: Celebrating 25 years of innovation in synchrotron engineering
2642
The 13th International Conference on Mechanical Engineering Design of Synchrotron Radiation Equipment and Instrumentation (MEDSI 2025) marks the 25th anniversary since the first MEDSI workshop in 2000. This biennial meeting, hosted by MAX IV Laboratory in Lund, Sweden, from September 15–19, 2025, is expected to welcome over 300 delegates and more than 30 industrial exhibitors. MEDSI is the leading forum for advancing engineering in synchrotron and free-electron laser (XFEL) facilities, featuring sessions on precision mechanics, photon delivery, simulation, and core technology developments. MEDSI 2025 will also introduce a special session on neutron source instrumentation, emphasizing collaboration with the European Spallation Source (ESS). The event includes invited and contributed talks, poster sessions, and an industrial exhibition, with all contributions published in the JACoW Proceedings. For more information, visit www.medsi2025.com.
Paper: THPB061
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPB061
About: Received: 19 May 2025 — Revised: 29 May 2025 — Accepted: 29 May 2025 — Issue date: 10 Jul 2025
THPB079
Investigation of properties of CuZr alloy for vacuum chamber structural materials
2644
CuZr alloy is considered for the structural material of the vacuum chamber of the Hefei Advanced Light Facility (HALF) storage ring. We tested the outgassing rate of CuZr material. The outgassing rate of CuZr alloy can reach 4.93×10^-11 Pa·L/s·cm² after baking at 180°C for 48h, which is more than one order of magnitude lower than that of SS. These results indicate that CuZr alloy is easier to degas by baking at lower temperatures and is a material with very low outgassing rates. At the same time, it is a highly competitive structural material for future accelerator vacuum chamber based on its good electrical conductivity, high strength and hardness.
Paper: THPB079
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPB079
About: Received: 17 May 2025 — Revised: 30 May 2025 — Accepted: 30 May 2025 — Issue date: 10 Jul 2025
THPB089
Recent progress at the Low Energy Accelerator Development Facility
2658
The Low Energy Accelerator Development Facility * is located at the site of the Brookhaven National Laboratory (Upton, NY, USA) and is aimed to run a program specially targeting new collaborations for user-driven research. The facility has two fully radiation-shielded bunkers (153 and 77 sq. m) to where a range of electrical, cooling and RF capabilities are presently being introduced. The facility runs also the Ultrafast Electron Diffraction (UED) Facility. The first shielded bunker will support the deployment of a demonstrator for the Electron Cyclotron Resonance Accelerator ** (eCRA). The deployment is expected to start in April of 2025. At the UED Facility beamline updates are now going into place for a NASA Jet Propulsion Laboratory *** electron irradiator beamline for Single Event Effects (SEE) testing; the capability for UED/UEM testing will be expanded; and the deployment of a new stable solid-state modulator and klystron is in progress. The presented article provides further details.
Paper: THPB089
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPB089
About: Received: 20 May 2025 — Revised: 31 May 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
THPB090
Accelerator test facility upgrades to enable further advancements in the science and technology of accelerators
2661
The Accelerator Test Facility* (ATF) is the DoE Office of Science User Facility aimed to provide users with a high brightness electron beam, near-infrared (NIR), and long-wave infrared (LWIR) laser beams. The unique capabilities at the ATF include the possibility to combine the electron beam with synchronized high-power laser beams. It is planned to upgrade the facility to have enhanced capabilities. They will include: an increased electron beam energy from the present 65-70 MeV to 110-120 MeV; a reduced by a factor of about 10 phase jitter; and an improved - to femtoseconds’ scale - time synchronization between the electron beam and the laser beams. To accomplish these tasks, the ATF will design and deploy a new High Level RF System, a new Low Level RF System, and a new Time Distribution System. In addition, the ATF will change the Power Plant for the quadrupole and correction magnets to increase operations’ reliability. It is expected that the planning stage will be completed in about 3 years, and the actual hardware deployment will be finished after that in the next 2 years. Different upgrade options are being investigated now and are described in the presented article.
Paper: THPB090
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPB090
About: Received: 21 May 2025 — Revised: 03 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
THPB094
Large-area atomic layer deposition of titanium nitride for RF windows
2668
High-power particle accelerators, like the Spallation Neutron Source, require reliable radio-frequency waveguide windows to transmit power while maintaining a vacuum. These windows face performance challenges due to multipacting, an electron cascade disrupting vacuum integrity. Thin TiN coatings can suppress this by reducing secondary electron emission, but traditional methods struggle to uniformly coat complex ceramic surfaces. We developed an atomic layer deposition (ALD) process to create conformal TiN films (<10 nm) at low temperatures (130°C), achieving smooth, conductive coatings with a secondary electron yield below 2.0. Collaborating with Microwave Techniques LLC and Oak Ridge National Laboratory, we designed RF windows with replaceable TiN-coated ceramic disks to improve performance and reduce downtime. In our next phase, we will scale up manufacturing and develop a modular ALD tool for in-situ coating of waveguide and SRF cavity metallic surfaces, crucial for next-generation accelerators operating at higher power. These innovations enhance efficiency, reliability, and design flexibility, advancing accelerator technology and fostering high-tech sector growth.
Paper: THPB094
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPB094
About: Received: 30 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
THPM002
VHEE FLASH radiotherapy: cutting-edge research at CLEAR, the CERN Linear Electron Accelerator for Research
2691
With the current availability of cost-effective and compact electron LINACs operating in the 100-200 MeV energy range, there has been a growing interest in using Very High Energy Electron (VHEE) radiotherapy (RT) for cancer treatment. A particularly intriguing aspect is the Ultra High Dose Rate (UHDR) or FLASH dose regime, which focuses on damaging cancerous cells while sparing healthy tissues. VHEE beams are well-suited for FLASH RT, given their deep penetration and high beam current, making them effective for treating large, deep-seated tumors. The CLEAR (CERN Linear Electron Accelerator for Research) facility has been at the forefront of exploring VHEE and FLASH RT, conducting numerous unique experiments in collaboration with multidisciplinary user groups having experience in dosimetric, chemical, and biological studies. This paper introduces recent measurements, techniques, and methods used to observe the FLASH effect at CLEAR.
Paper: THPM002
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPM002
About: Received: 27 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
THPM010
Using machine learning techniques for BGI-based profile measurements at the CERN PS
2707
The Beam Gas Ionization (BGI) instrument provides a non-destructive method for monitoring transverse beam profiles by detecting free electrons produced during beam-gas ionization. Utilizing a Timepix-family detector, the BGI setup at the CERN Proton Synchrotron (PS) includes two instruments dedicated to horizontal and vertical plane measurements. However, the quality of these measurements is often compromised by artifacts, such as beam losses, which degrade profile quality, make the analysis significantly more difficult and ultimately affect the instrument performance. To address these challenges, this contribution explores the application of machine learning techniques for effective background removal. Both supervised and unsupervised approaches are evaluated on data acquired from the operational systems to improve the accuracy and reliability of the reconstructed profiles. Furthermore, the computational performance and time complexity of these methods are evaluated to ensure that the proposed solutions are compatible with the operational requirements of the BGI system.
Paper: THPM010
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPM010
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
THPM031
Beam Energy Forecasting using Machine Learning at the CLEAR accelerator
2747
In particle accelerators, accurate and stable beam parameters are crucial for experimental success. Traditional methods for measuring parameters like beam energy often rely on invasive techniques that disrupt experiments. This paper presents a novel, non-invasive machine learning-based approach to predict beam energy using parasitic measurements, enabling real-time estimation without interference. The method employs a predictive model optimized for one-step-ahead forecasting and uses time-series data decomposition to handle complex beam energy dynamics. Recursive prediction strategies allow the model to anticipate future variations autonomously. Preliminary results from experiments at the CLEAR accelerator demonstrate the model’s ability to capture both slow trends and rapid energy shifts, adapting to diverse experimental needs. These findings showcase the potential of machine learning to measure beam energy, offering a real-time, non-destructive alternative to conventional methods. This approach promises significant advancements in accelerator-based applications, especially where destructive techniques are impractical.
Paper: THPM031
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPM031
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 06 Jun 2025 — Issue date: 10 Jul 2025
THPM034
MTE measurements at the ASU cryogenically cooled DC electron gun
2755
The ASU cryogenically cooled DC electron gun represents a state-of-the-art platform for testing novel photocathodes at room and cryogenic temperatures. The key electron beam diagnostic tool of this setup is the four-dimensional (4D) phase space reconstruction using the pinhole scan technique. In this work, we use the 4D phase space measurement to extract the Mean Transverse Energy (MTE) obtained from cathodes in this gun. We also establish the limits and accuracy of the 4D phase space and emission area measurements and estimate their effects on the MTE extracted. The results, validated through simulations and complementary measurements establish the use of the 4D phase space measurement technique to obtain the MTE. Using this approach, we measure the MTE from alkali antimonide photocathodes at varying temperature and electric field conditions. This study provides a robust foundation for future experiments with the ASU electron gun and beamline, paving the way for advanced photocathode characterization under cryogenic conditions.
Paper: THPM034
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPM034
About: Received: 28 May 2025 — Revised: 31 May 2025 — Accepted: 01 Jun 2025 — Issue date: 10 Jul 2025
THPM037
Longitudinal beam size measurement at the Novosibirsk FEL
2762
The Novosibirsk Free Electron Laser (NovoFEL) is a facility that consists of three free electron laser (FEL) systems installed on different parts of the Energy Recovery Linac (ERL). These three FELs share the same acceleration system, which enables the generation of high average electron current, typically around 10 mA. Precise measurement of the electron beam parameters is essential for monitoring the performance of the accelerator and tuning its operating modes. One of the most important parameters is the length of the electron bunch, as it directly affects the efficiency of the laser radiation generation process. This paper presents the results of experiments conducted to study the behavior of the longitudinal beam size in various Novosibirsk FEL lasers. For these experiments, we used Cherenkov radiation produced by a beam of electrons passing through a thin aerogel plate. The resulting flash of radiation was captured by a streak camera, allowing us to determine the longitudinal size of the electron beam. The results of the study on the dependence of the longitudinal beam size on various accelerator parameters are presented.
Paper: THPM037
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPM037
About: Received: 27 May 2025 — Revised: 30 May 2025 — Accepted: 01 Jun 2025 — Issue date: 10 Jul 2025
THPM043
Performance assessment of profile monitors at CERN’s LHC using systematic analysis tools
2777
In this paper, we investigate statistical and systematic tools to establish performance benchmarks for future beam profile measurement tools, using extensive data from both prototype and legacy Beam Wire Scanners and the Beam Synchrotron Radiation Telescope at the LHC. We detail direct and comparative analyses, including variability in beam size measurements, positioning accuracy, and profile shape fidelity relative to theoretical models, with particular focus on non-Gaussian tails influenced by the beam halo effect. This work establishes a foundation for systematic performance assessment applicable to both current and next-generation profile measurement tools.
Paper: THPM043
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPM043
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
THPM050
Study of laser-beam arrival time synchronization towards sub-picosecond stability level
2800
In order to achieve laser pulse to electron beam arrival time sub-picosecond stability at the accelerator facilities, a new Low-Level Radio-Frequency system clock generators synchronization architecture is currently under investigation in collaboration between KEK (Japan) and IJClab (France). The system is based on the 10 MHz frequency generator (Stanford Research System), White Rabbit Switch, SkyWorks Si5362 clock generator and IDROGEN boards. This report demonstrates the measurement results of the long-term and short- term synchronization between clock generators. Also, the architecture details are discussed in this report.
Paper: THPM050
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPM050
About: Received: 27 May 2025 — Revised: 01 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
THPM063
Extended phase space tomography for EOSD simulation considering crystal geometry effects
2818
This theoretical study presents an advanced method for longitudinal phase space tomography in electron storage rings, focusing on reconstructing phase space densities from electro-optical spectral decoding (EOSD) measurements that incorporate crystal geometry effects. The EOSD crystal geometry significantly impacts the measurement signal due to signal integration along its length and interference from wake fields and Cherenkov diffraction radiation (ChDR). These effects add challenges to reconstructing the original phase space density from experimental data. To address these challenges, we integrate two theoretical frameworks. First, we employ the Vlasov-Fokker-Planck equation to model the turn-by-turn evolution of the charge density distribution. Second, CST simulations of the bunch profile characterize the electric field inside the crystal, enabling a tailored simulation for the EOSD system at the Karlsruhe Research Accelerator (KARA). By combining these approaches, we propose a refined tomography method that more accurately reconstructs the longitudinal phase space from sensor data, effectively capturing the interplay between bunch dynamics and the EOSD system configuration.
Paper: THPM063
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPM063
About: Received: 23 May 2025 — Revised: 01 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
THPM064
Terahertz streaking detection for longitudinal bunch diagnostics at FLUTE
2822
The Karlsruhe Institute of Technology is currently exploring a compact method of longitudinal electron bunch diagnostics with femtosecond resolution that has recently been demonstrated for other parameter ranges. The experimental setup utilizes a THz-based streaking approach with resonator structures, achieving both high compactness and efficiency. In this paper, we report on the experimental observation of streaking signals with our Compact Transverse Deflecting System, which has been successfully tested using two different resonators, an Inverse Split-Ring Resonator and a Tilted-Slit-Resonator.
Paper: THPM064
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPM064
About: Received: 28 May 2025 — Revised: 01 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
THPM072
The online emittance monitor at Taiwan Photon Source
2839
This study summarizes the X-ray pinhole camera results from two recently constructed diagnostic beamlines. We provide updated emittance and energy spread measurements for the TPS storage ring and implement online measurements for routine operational monitoring.
Paper: THPM072
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPM072
About: Received: 19 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
THPM076
Progress towards longitudinal bunch profile monitor at the Argonne Wakefield Accelerator employing phase diversity electro-optic sampling
2848
Precise measurement of an electron bunch’s longitudinal profile is critical for wakefield accelerators as shaped electron bunches can improve transformer ratios in collinear wakefield acceleration. Electro-Optic sampling of terahertz (THz) radiation from the bunch is one of the most attractive approaches to provide a view into the structure of a relativistic electron bunch due to its non-destructive nature. Recent developments in spectral encoding methods have shown that Phase Diversity Electro-Optic Sampling (DEOS) can accurately retrieve profiles from both sub-picosecond bunches and those requiring long sampling time windows near the traditional resolution limits. We report the progress on DEOS measurements using coherent transition radiation (CTR), as well as simulations of retrieved THz fields from arbitrary shaped electron bunches using various crystal and probe-laser configurations.
Paper: THPM076
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPM076
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
THPM087
Possibilities for performance enhancement of a compact TDS at FLUTE
2862
A compact transverse-deflecting system (TDS) is being commissioned at the test facility FLUTE (Ferninfrarot Linac- und Test-Experiment) located at the Karlsruhe Institute of Technology (KIT). It has been proposed for diagnostics of short electron bunches. The idea of the technique is to use terahertz (THz) radiation, produced by the tilted-pulse front method using a part of the facility’s photoinjector laser, amplified by a sub-mm scale resonator for streaking of the electron bunch. Two types of resonators and their arrays have been studied: inverse split-ring and tilted slit resonator. Since the temporal resolution of this technique depends strongly on the electric field strength in the resonator gap, it would be desirable to increase this field strength. A horn-antenna-like device placed near the resonator has been proposed and simulated for this purpose. Simulations and geometrical parameter optimization have been performed using CST MICROWAVE STUDIO and will be presented in this contribution.
Paper: THPM087
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPM087
About: Received: 28 May 2025 — Revised: 01 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
THPM088
Preliminary investigation on single-pixel Schottky diode based ultra-broadband THz detectors with ps-scale temporal resolution for future BCMs
2866
A Terahertz (THz) transition radiation monitor, as part of a Bunch compression monitor (BCM), is implemented for longitudinal bunch diagnostics at FELs such as ELBE, FLASH, or EuXFEL. Pulse energy measurements are typically carried out after each bunch compressor stage using coherent diffraction radiation (CDR) in the THz domain and pyroelectric detectors. For higher repetition rates in the MHz range, complex correction algorithms must be applied to correct signal pileup of the pyro-electric detector output, as well as limited signal-to-noise ratio, which can be overcome by using THz detectors with ultra-flat frequency response up to several THz. This work exhibits preliminary studies on developing an ultra-flat frequency response THz spectrometer. We present the developed single-pixel Schottky diode-based THz detector capable of single-shot measurements with a response time of 28.5 ps and IF bandwidth of $\sim$70 GHz. Further, the simulation result from the Schottky diode parameters is presented.
Paper: THPM088
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPM088
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
THPM090
Study of Cherenkov diffraction radiation from radiator with periodic structure in THz-region
2874
We have studied classical radiation from relativistic electrons at a facility, test accelerator as a coherent terahertz source (t-ACTS), the Research Center for Accelerator and Radioisotope Science (RARiS), Tohoku University. Cherenkov radiation is generated when a relativistic charged particle passes through a dielectric medium, while Cherenkov diffraction radiation (ChDR) is emitted when the relativistic charged particle passes near the dielectric medium. In general, the ChDR spectrum is broadband. However, when a periodic structure is used as a radiator, interference effects can monochromatize the ChDR. At t-ACTS, a proof-of-principle experiment in the THz region was conducted using a high-density polyethylene (HDPE) radiator with a periodic structure. We successfully measured ChDR from radiator with periodic structure and achieved narrowband ChDR (NbChDR) in the THz region. This paper will discuss the characteristics of NbChDR in the THz region, as observed at t-ACTS.
Paper: THPM090
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPM090
About: Received: 26 May 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
THPM096
Top-up safety simulations for Elettra 2.0
2886
A comprehensive program of tracking studies has been carried out to ensure that no train of injected electron bunches can traverse an open beamline during top-up operations at Elettra 2.0. The analysis explored various error scenarios, considering realistic magnetic field variations, trajectory shifts, aperture constraints, and energy deviations. This paper presents the tracking techniques employed, the scenarios investigated, and the proposed interlock systems designed to ensure safety during top-up operations.
Paper: THPM096
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPM096
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
THPM109
Operational results of data-driven automated intensity optimization at CERN’s LEIR
2913
At CERN’s Low Energy Ion Ring (LEIR), high beam intensities are achieved through phase space painting with up to eight multi-turn injections from the linear accelerator Linac3. After each injection, the beam is cooled and stacked in longitudinal phase space using an electron cooler. During beam operation, key parameters such as RF cavity phases in the linac, the LEIR electron cooler gun voltage, and various magnetic field strengths along the transfer line must be frequently adjusted to compensate for the injection performance degradation occurring over time. The primary cause is the aging of the stripper foil, a thin carbon plate which strips off electrons from the passing ions, altering the energy of the beam injected from the linac. Time of flight measurements in the linac and Schottky signals in the ring provide the necessary diagnostics for correcting the performance degradation and can be encoded to provide a state for an optimizer. In this paper, we compare several data-driven methods, such as Bayesian Optimization and Reinforcement Learning for designing an autonomous controller to optimize and maintain injection performance during both beam commissioning and physics runs.
Paper: THPM109
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPM109
About: Received: 26 May 2025 — Revised: 02 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
THPM111
Characterization of an IRRAD beam profile monitor at the CERN T8 beamline and possible improvements via cross-analysis with multiwire proportional chamber
2921
A new Beam Profile Monitor (BPM) system has been recently developed at the IRRAD Proton Facility to monitor the high-intensity 24 GeV/c proton beam from the CERN Proton Synchrotron accelerator. Thanks to the use of a new sensor manufacturing technology based on the microfabrication of metal nano-layers and updated readout electronics based on a Charge-Sensitive Amplifier with integrated 20-bit ADC and ARM controller, this system features minimal particle interaction, improved radiation hardness and higher sensitivity than earlier solutions. The growing users’ demand for precise irradiation of modern electronics, requiring ever more detailed beam information, is driving the introduction of future IRRAD upgrades, by leveraging on the presence of additional detector, a Multiwire Proportional Chamber, a detailed comparison-based analysis was performed to better characterize the IRRAD BPM system. It allowed us to introduce improvements in beam monitoring via advanced software and data processing. These results are crucial for future improvements at IRRAD by formulating requirements for the profile monitoring of new types of beams in IRRAD, e.g. heavy-ion and low-intensity proton beams.
Paper: THPM111
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPM111
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
THPS007
Oxygen deficiency detection in the LHC
2952
With the increased performance of the High Luminosity Large Hadron Collider (HL-LHC), gas leak detection in the vicinity of the superconducting magnets cooled with cryogenic helium becomes a challenge. To ensure operational safety and reliable detection of Oxygen Deficiency Hazard (ODH) for the next decade, the entire system will be refurbished during the LHC accelerator's long shutdown, scheduled to begin in 2026. The new design of the ODH detection system includes development of a detector and flashing lights that can not only cope with electromagnetic disturbances, but also with an increased radiation exposure, all while considering the restricted access for equipment maintenance. Understanding the nature and impact of these constraints at the design stage is key to specifying the requirements of the new safety systems. This paper describes the research and development work undertaken by CERN to analyse, test, and define oxygen deficiency detection taking into account lessons learned from the current systems and the future upgrade to the High Luminosity LHC.
Paper: THPS007
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPS007
About: Received: 19 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
THPS024
Radiation monitoring and R2E performance in the LHC during the 2024 proton run
3006
The integrated luminosities in each of the ATLAS and CMS experiments at the Large Hadron Collider (LHC) have reached above 120 fb-1 during the proton run of 2024, the highest annual values since the beginning of the LHC operation. The same is true for LHCb, with over 10 fb-1 of integrated luminosity reached during proton operation in 2024. Such high levels of integrated luminosity are associated with high levels of radiation around the experiment locations, including hundreds of meters of tunnel on both sides of the interaction point, where beam losses driven by the luminosity production still occur. The ability of the LHC systems to operate in the radiation environment of the machine is analyzed in this contribution. Each year, radiation effects on electronic components installed around the LHC lead to premature beam dumps, causing accelerator down-time and loss of physics production. The number of radiation-induced beam dumps of the proton run 2024 per integrated luminosity has been comparable to previous years in LHC Run 3, and improved compared to LHC Run 2. However, due to the large integrated luminosity of LHCb, a large part of the events have been observed there, and some mitigation strategies to minimize such events are discussed.
Paper: THPS024
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPS024
About: Received: 27 May 2025 — Revised: 02 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
THPS030
Auxiliary tools for TPS operation
3030
This article provides an overview of various software tools developed by operators to enhance TPS operations. The primary functionalities of these tools include real-time monitoring and notification of light source statuses, as well as data analysis. The tools covered include the TPS alarm system, LINE notification system, real-time orbit deviation display, real-time fast corrector output display, pulse magnet waveform recording and analysis, parameter value changelog, and tools for comparing power supply readings, eBPMs, ID gaps, and XBPM differences between different time points. Each of these tools will be explained in detail throughout the article.
Paper: THPS030
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPS030
About: Received: 20 May 2025 — Revised: 30 May 2025 — Accepted: 01 Jun 2025 — Issue date: 10 Jul 2025
THPS048
eLog analysis for accelerators: status and future outlook
3076
This work demonstrates electronic logbook (eLog) systems leveraging modern AI-driven information retrieval capabilities at the accelerator facilities of Fermilab, Jefferson Lab, Lawrence Berkeley National Laboratory (LBNL), SLAC National Accelerator Laboratory. We evaluate contemporary tools and methodologies for information retrieval with Retrieval Augmented Generation (RAGs), focusing on operational insights and integration with existing accelerator control systems. The study addresses challenges and proposes solutions for state-of-the-art eLog analysis through practical implementations, demonstrating applications and limitations. We present a framework for enhancing accelerator facility operations through improved information accessibility and knowledge management, which could potentially lead to more efficient operations.
Paper: THPS048
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPS048
About: Received: 10 Jun 2025 — Revised: 14 Jun 2025 — Accepted: 14 Jun 2025 — Issue date: 10 Jul 2025
THPS060
Photon stimulated desorption from cryogenic surfaces of high temperature superconductor and amorphous carbon thin films
3101
High Temperature Superconductor (HTS) and amorphous Carbon (a-C) thin films, and their combination, are being considered as possible surface coatings for the FCC-hh beam screen (BS) with the aims of reduction of the resistive wall impedance and mitigation of the electron cloud. Along with these required properties, i.e., the high electron conductivity and low secondary electron yield, the Photon Stimulated Desorption (PSD) yield is one of the most essential characteristics in the design and operation of the FCC-hh vacuum systems. For this purpose, a series of the PSD measurements is currently conducted at a dedicated beamline in the KEK Photon Factory, where similar conditions to FCC-hh in terms of the Synchrotron Radiation energies and power density are available. In order to realize a similar cryogenic condition of the BS (40-60 K), the sample container is equipped with a LN2 jacket (77 K) and installed in an insulation vacuum chamber. The conditioning behaviors of the PSD yields as a function of the photon dose are being obtained for uncoated copper and HTS, and a-C coated copper and HTS, and each sample is examined at cryogenic and room temperatures for comparative analysis.
Paper: THPS060
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPS060
About: Received: 31 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
THPS079
First prototype measurements with an electro-optical bunch profile monitor for FCC-ee
3125
The future circular electron-positron collider (FCC-ee) is designed for highest luminosity to enhance the precision of high-energy particle physics experiments, spanning energies from the Z pole to the $\text{t}\bar{\text{t}}$ threshold. As outlined in its conceptual design report, high-precision measurements of the longitudinal bunch profile are required across multiple operation modes, which presents key challenges for beam instrumentation. As part of the feasibility study, a concept for an electro-optical (EO) bunch profile monitor has been developed to address these challenges, building on the existing EO beam diagnostic at the Karlsruhe Research Accelerator (KARA) at KIT. The first EO monitor prototype for FCC-ee features a novel crystal-holder design using prisms, enabling a single-pass setup crucial for measuring the long bunches during Z operation. This contribution presents the first measurement results of the EO monitor prototype for FCC-ee, which were obtained in the in-air test stand at the CERN Linear Electron Accelerator for Research (CLEAR).
Paper: THPS079
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPS079
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
THPS082
Impact of beam background and jitter on LUXE interaction point
3129
LUXE is an international project that aims to study Quantum Electro-Dynamics processes that occur in the strong field regime. Using the electron beam from the European XFEL, this experiment will perform electron-laser and photon-laser collisions. Beamline simulations are required to understand what beam properties and backgrounds are expected at key locations. The beam optics was design and simulated with MAD-8 and this used to create a BDSIM simulation. To perform high precision interactions it is crucial that the transverse size and position of the electron beam can be measured. The variation of the beam position over time also has impacts on an efficient collision with the laser. This study uses simulated virtual measurement, wire scanning methods, and real measurements at the XFEL to evaluate those parameters. Finally, background from both the upstream beam line and the different dumps must be estimated to ensure that the impacts on the experiment are low enough. This paper present BDSIM simulations with high statistics necessary to evaluate the background. Critical for BDSIM studies is finding optimised ways to do cross-section biasing and final state splitting in the dumps.
Paper: THPS082
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPS082
About: Received: 27 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
THPS083
Investigating beam-induced electron emission from thin wires in PSI proton beams
3133
The emission of electrons induced by beam interaction with thin targets is a phenomenon used to measure various properties of particle beams. The main processes of electron emission are: secondary emission, delta electron production and thermionic emission. The last one is not desired, because the intensity of thermionic electrons is not directly related to beam density profile. A common technique to suppress thermionic emission employs bias potential on the wire, which allows for recapturing of low energy electrons. This study investigates the effectiveness of the bias voltage method for high-brightness proton beams of the HIPA accelerator. Through experiments and simulations, the study aims to better understand the emission spectra, the suppression of thermionic emission, and the effects of beam fields on electron dynamics.
Paper: THPS083
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPS083
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
THPS094
Characterisation of the foreseen turn-by-turn beam position instrumentation for the cSTART storage ring
3154
The KIT cSTART project (compact storage ring for accelerator research and technology) aims to demonstrate injection and storage of a high intensity ultra-short bunch using the FLUTE LINAC, as well as a laser-plasma accelerator (LPA). cSTART is planned to operate with a wide range of demanding parameters, such as bunch charge, bunch length and energy spread (from the LPA), making it extremely challenging for the choice of beam diagnostics with large dynamic ranges that are capable of operating within specifications. Moreover, turn by turn measurements are necessary in the cSTART storage ring as bunch characteristics are expected to dramatically change within a single turn. In this paper, we will describe the planned beam diagnostics system of the cSTART storage ring focusing on the turn-by-turn signal processing and reporting on characterization tests which were performed.
Paper: THPS094
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPS094
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
THPS095
New all-digital camera setup at the Karlsruhe Research Accelerator
3158
Until recently, the Karlsruhe Research Accelerator (KARA) located at the Karlsruhe Institute of Technology (KIT) was using analog cameras to monitor fluorescence screens. By now all cameras have been replaced by digital cameras directly connected via ethernet, making it possible to directly integrate them into our EPICS-based control system. The new control system integration also provides for a better continuous statistical analysis and comparison of camera pictures. This paper presents an overview of the new setup, including the post-processing integration making use of Python.
Paper: THPS095
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPS095
About: Received: 28 May 2025 — Revised: 31 May 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
THPS097
Minimizing disturbance in ion beam profiling with PEPITES monitor
3162
In the field of beam diagnostics for radiotherapy, accurate dose delivery relies on ultra-thin, linear and radioresistant monitors to minimize beam scattering and achieve precise profiling. The first PEPITES prototype monitor features two segmented cathodes, each paired with a high-voltage-biased anode. This latter effectively captures secondary electrons generated by the cathodes when they interact with the beam, enabling the detection of a measurable signal. The Water Equivalent Thickness (WET) of this design is approximately 10 μm*. To achieve efficient profiling of the charged particle beam when the monitor is positioned several meters upstream of the patient, we developed a thinner design. This configuration features two anodes positioned outside the beam path, reducing by half the amount of material that interacts with the beam, thereby minimizing beam disturbances. Both, the previous and the updated PEPITES monitor designs were recently tested at CNAO,Italy. Measurements were successfully conducted using a 115 MeV carbon ion beam at varying high-voltage power. These results will be presented and compared to demonstrate the enhanced efficiency of the upgraded PEPITES version.
Paper: THPS097
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPS097
About: Received: 01 Jun 2025 — Revised: 02 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
THPS103
Optical electron beam diagnostics at the Novosibirsk FEL
3170
We present an overview of recent and upcoming enhancements to the optical electron beam diagnostics stations at the Novosibirsk Free Electron Laser (FEL) facility. These diagnostic stations are designed to measure key beam parameters, including beam energy spread, length and emittance, at the third FEL of Novosibirsk FEL. Currently, the stations for measuring electron beam energy spread and undulator radiation spectrum are in the commissioning phase, with initial results already obtained. The new optical diagnostics are essential for the precise tuning of the magnet system used in electron outcoupling experiments. This paper provides a comprehensive overview of the new diagnostic systems, discusses the preliminary measurement results of beam parameters, and outlines the experiments planned for the near future.
Paper: THPS103
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPS103
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
THPS104
Development and testing of an autocorrelator for measuring the duration of picosecond pulses of near infrared radiation
3174
The paper presents a design of an autocorrelator manufactured to measure the duration of infrared picosecond pulses of radiation from the 3rd laser of the Novosibirsk Free Electron Laser facility, as well as the results of testing the autocorrelator when measuring the duration of picosecond pulses in the visible range. The results and future plans for future experiments using developed autocorrelator
Paper: THPS104
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPS104
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
THPS107
Substrate material studies for PCB-based electro-optical bunch arrival-time monitors for XFELs
3181
The all-optical synchronization system used in many X-ray free-electron laser facilities (XFELs) relies on electro-optical bunch arrival-time monitors (EO-BAM) for measuring the single bunch arrival time with regards to an optical reference. An upgrade of the established EO-BAM is intended to achieve a sensitivity that enables stable operation with bunches down to charges of 1 pC, or to significantly increase the resolution in normal operation. Therefore, the pickup structure, the RF path and the electro-optical modulators are undergoing a fundamental redesign. The novel concept of the pickup structure comprises planar pickups on a printed circuit board (PCB) with integrated combination network and a bandwidth of up to 100 GHz. The theoretical jitter charge product of the preliminary concept has been estimated to be in the order of 9 fs pC and the concept was proven experimentally with a 67-GHz demonstrator at ELBE. In this contribution, we compare ceramic and glass substrates in terms of radiation hardness, sensitivity, and manufacturing capabilities. The achievable bandwidth and sensitivity are influenced by material losses and varying tolerances due to different fabrication methods.
Paper: THPS107
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPS107
About: Received: 28 May 2025 — Revised: 31 May 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
THPS127
Design of RF duct shielding for the SPS-II 3-GeV electron storage ring
3219
The Siam Photon Source II (SPS-II) is a fourth-generation synchrotron light source designed to provide high-brightness, low-emittance, high-energy electron beams for advanced synchrotron applications. SPS-II is equipped with a 150-MeV linear accelerator, a 3-GeV booster synchrotron, and a 3-GeV electron storage ring, enabling the production of high-quality synchrotron radiation for a wide range of scientific research fields. The 500 MHz RF system in the storage ring serves to replenish the energy lost by electrons due to synchrotron radiation. RF cavities generate oscillating electromagnetic fields at a specific frequency, accelerating the electrons each time they pass through the cavity. The RF ducts house the waveguides and transfer RF power to the RF cavities inside the storage ring tunnel. However, penetration in the storage ring tunnel may allow radiation within the shielding tunnel to leak outside the shielding. For this reason, the design of the RF ducts must be carefully considered. The FLUKA particle transport code is used to investigate the shielding. The results indicate that the radiation dose is below the design criterion, meeting the radiation safety standards.
Paper: THPS127
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPS127
About: Received: 27 May 2025 — Revised: 30 May 2025 — Accepted: 30 May 2025 — Issue date: 10 Jul 2025
FRZD1
Latest achievements in femtosecond synchronization of large scale facilities
3256
The laser-based synchronisation systems for the European XFEL and FLASH provide femtosecond-stable timing references for tens of clients along the accelerator and the experiment halls over many kilometres of optical fibre. Recently, benchmarking experiments revealed a point-to-point timing stability with sub-femtosecond rms timing jitter. At the same time geophysical effects like ocean waves and earthquakes do not only affect the performance of the system, but their impact can clearly be identified. To improve the temporal resolution in X-ray/optical pump-probe experiments, additional arrival time monitors for both the electrons and the optical laser pulses are currently being installed, allowing for a posteriori data sorting and eventually active feedbacks. Further, the optical reference oscillators and advanced synchronisation schemes are being developed, resulting in timing jitter on the sub-hundred attoseconds level.
Paper: FRZD1
DOI: reference for this paper: 10.18429/JACoW-IPAC25-FRZD1
About: Received: 30 May 2025 — Revised: 31 May 2025 — Accepted: 01 Jun 2025 — Issue date: 10 Jul 2025
FRZD2
BeamPIE – a suborbital test of an accelerator for space applications
3261
Summary: An experiment to fly an accelerator in space recently concluded successfully. Discuss the objectives, differences from terrestrial accelerators, and results from the flight. Accelerators have the potential to play a major role in space-based activities. These can range from investigation of the Earth’s magnetic field, to helping mitigate the effects of increased solar activity (e.g. by helping drain the Earth’s radiation belts of charged particles), to deep-space missions. There are many challenges associated with operating accelerators in a space-based environment, however, ranging from high-voltage systems, to thermal management, to spacecraft charging. The Beam-Plasma Interaction Experiment – BeamPIE – was a small electron accelerator launched on a sounding rocket in 2023, to both explore the interaction of an electron beam with the near-earth plasma environment, and to test several new approaches to accelerator design in a space environment. This talk presents an overview of the BeamPIE accelerator design, mission objectives, and results from its flight.
Paper: FRZD2
DOI: reference for this paper: 10.18429/JACoW-IPAC25-FRZD2
About: Received: 24 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
FRZD3
Highlights from Future Circular Collider Feasibility Study and Path to Construction
3266
The proposed Future Circular Collider (FCC) integrated programme consists of two stages: an electron–positron collider serving as a Higgs-boson, electroweak and top-quark factory,followed by a proton–proton collider operating at a collision energy around 100 TeV. In 2021, in response to the 2020 update of the European Strategy for Particle Physics, the CERN Council initiated the FCC Feasibility Study. This study covered, inter alia, physics objectives and potential, geology, civil engineering, technical infrastructure, territorial implementation, environmental aspects, R&D needs for the accelerators and detectors, socio-economic benefits, and cost. The FCC Feasibility Study was completed on 31 March 2025. We present a few key results along with accelerator R&D goals and discuss the next steps.
Paper: FRZD3
DOI: reference for this paper: 10.18429/JACoW-IPAC25-FRZD3
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025