timing
MOBC02
Performance study of Fast Beam Current Transformer calibration in the LHC
7
Fast Beam Current Transformers (FBCTs) are essential devices for measuring bunched beam intensities in the Large Hadron Collider (LHC). A cross-calibration of these devices against DC Beam Current Transformers (DC-BCTs) is used in the LHC ring, but this method relies on assumptions that introduce inaccuracies. FBCTs are also used in the LHC transfer lines, where DC-BCTs are unavailable, making absolute calibration crucial for transmission studies. To allow absolute calibration, the FBCTs are equipped with a pulsed current source to perform a calibration before each fill. However, a systematic underestimation in the calculated scaling factors has been observed when comparing them to the cross-calibration with the DC-BCTs. This work characterizes the calibrator performance, evaluates different algorithms for calculating the scaling factors and reports on issues found linked to processing chain modeling inaccuracies, ghost/satellite bunches, and the FPGA-based digital integration. A revised model of the processing chain improved calibration accuracy by 0.4%, while an initial test of a batch-by-batch baseline in the digital integration seems to explain the remaining 3% underestimation.
Paper: MOBC02
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-MOBC02
About: Received: 03 Sep 2025 — Revised: 06 Sep 2025 — Accepted: 06 Sep 2025 — Issue date: 20 Jan 2026
MOCI01
Commissioning and First Operation of SLS 2.0, the Upgrade of the Swiss Light Source
30
After more than 20 years of successful operation, the storage ring of the Swiss Light Source (SLS) has recently been replaced with a new diffraction-limited storage ring (DLSR) called SLS 2.0. After a dark time of 15 months from October 2023 until December 2024, SLS 2.0 now provides more than 40 times higher brilliance for hard X-ray users, thanks to an innovative compact 7-bend achromat magnet lattice with reverse bending magnets that fits into the old SLS 1.0 tunnel. In this contribution, we give an overview of the commissioning of the new storage ring and first user operation experience, highlighting key differences between SLS 1.0 and 2.0, as well as the role and usage of different beam instrumentation systems during the commissioning process from the operations perspective. Moreover, we present the status of beam-based feedbacks systems, and the resulting beam stability and performance that has been achieve so far during first user operation.
Paper: MOCI01
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-MOCI01
About: Received: 08 Sep 2025 — Revised: 08 Sep 2025 — Accepted: 09 Sep 2025 — Issue date: 20 Jan 2026
MODC02
Performance analysis of the LHC BSRL and possible improvements
35
The Beam Synchrotron Radiation Longitudinal density monitor (BSRL) at the LHC leverages time-correlated single-photon counting to provide high-dynamic-range measurements of the relative charges in each RF bucket with a time resolution of 50 ps. These measurements are needed for the operation of the LHC as well as for the luminosity calibration required by the LHC Experiments. In this work we identify sources of error for each the BSRL components. These components are the optics (mirrors, filters and optical fibres), the detector (a hybrid photomultiplier - HPM), the electronics (a Time to Digital Converter - TDC) and some data analysis used for the final results. Knowledge of the errors of the BSRL is crucially important as any errors are passed directly into the luminosity calibration of the LHC experiments. We quantify the errors introduced by each of these parts and for external systems, like the LHC timing. For the largest contributors to the overall error, we propose mitigation strategies that can be deployed in the short term.
Paper: MODC02
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-MODC02
About: Received: 03 Sep 2025 — Revised: 09 Sep 2025 — Accepted: 10 Sep 2025 — Issue date: 20 Jan 2026
MOPCO01
End to end simulations of a novel optical fibre monitoring system for energy recovery LINACs
46
Energy recovery LINACs (ERLs) are a type of novel accelerator, which recycle energy from old beams to new beams to increase machine energy efficiency. However, this can heighten beam instabilities, which limits the maximum beam current and increases beam losses. An optical fibre beam loss monitor (OBLM) can provide rapid and reliable beam loss monitoring, which is important for mitigating these instabilities. It obtains the beam loss location via time-of-flight analysis of Cherenkov radiation (CR) produced in optical fibres by relativistic particle showers from beam loss events. Operational demonstration of the OBLM system has previously been shown at several non-ERL facilities, but the multi-energy, fast-repeating beams of ERLs present a unique challenge. Successful interpretation of ERL beam loss signals involves distinguishing losses from beams of different energies, which can be investigated through end-to-end Monte Carlo simulations of the radiation environment and its interaction with the OBLM system. This contribution presents Geant4 simulations of the OBLM response to sample sources of beam loss for beam energies of 7-500 MeV and bunch populations of 1-10M electrons.
Paper: MOPCO01
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-MOPCO01
About: Received: 26 Aug 2025 — Revised: 04 Sep 2025 — Accepted: 08 Sep 2025 — Issue date: 20 Jan 2026
MOPCO02
PREDICTION OF FEL PERFORMANCE USING BPM MEASUREMENTS AND MACHINE LEARNING
50
This study developed and validated a machine learning approach to analyze the correlation between beam position monitor (BPM) measurement data and output laser power in the Hefei Infrared Free-Electron Laser (FEL) facility. Using transverse position, charge, and longitudinal phase information from 280 individual bunches collected by BPM probes upstream of the undulator, we successfully constructed a high-precision predictive model, demonstrating that BPM measurements can effectively predict the output laser power of the infrared FEL. Based on the trained predictive model, we further deconstructed the neural network architecture to accurately identify key bunches and sensitive parameters that most significantly influence laser power output. This provides a clear and targeted optimization basis for subsequent beam tuning experiments. The data-driven strategy employed in this method significantly reduces the workload associated with traditional experience-based tuning, offering an effective technical means to enhance accelerator operational stability.
Paper: MOPCO02
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-MOPCO02
About: Received: 02 Sep 2025 — Revised: 07 Sep 2025 — Accepted: 08 Sep 2025 — Issue date: 20 Jan 2026
MOPCO04
Machine learning using beam loss monitors for DIAMOND-II
58
The slow losses measured by Beam Loss Monitors (BLMs) at synchrotron light source facilities offer useful but indirect insight into the state of the beam. Patterns arise across the set of BLMs depending on the movement of insertion devices, beam current, temperature, humidity, and other contributors. A variety of neural network models were designed and evaluated to model this behaviour under user beam operation to enable anomaly detection and aid fault investigations.
Paper: MOPCO04
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-MOPCO04
About: Received: 02 Sep 2025 — Revised: 04 Sep 2025 — Accepted: 08 Sep 2025 — Issue date: 20 Jan 2026
MOPCO05
LHC BLM SYSTEM AUTOMATIONS FOR FAULT DETECTION, DIAGNOSIS, AND ISSUE TRACKING
62
One of the principal roles of CERN’s Beam Loss Monitoring (BLM) system pertains to the protection of LHC’s superconducting magnets against quench-inducing beam losses. Thus, the continuous surveillance of the BLM system’s performance is essential for the high reliability and availability of the LHC. This paper focuses on the architecture of a novel data pipeline with implementations on monitoring the communication status between the 864 acquisition tunnel modules that digitize the analog loss measurements, and the 432 processing surface modules that determine and act upon the criticality of the beam losses. The discussed pipeline replaces an older batch Extraction-Transformation-Loading (ETL) process, which published daily BLM status reports, in favor of a streaming ETL process. The new pipeline expands beyond the daily publication of static status reports by exploiting real-time data analysis and processing enabling the live assessment of the system’s status via online fault detection and web-based dashboards. Future development on the implemented pipeline envisions online machine learning and automated Jira issue generation features permitting fault prognosis and issue tracking.
Paper: MOPCO05
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-MOPCO05
About: Received: 03 Sep 2025 — Revised: 05 Sep 2025 — Accepted: 09 Sep 2025 — Issue date: 20 Jan 2026
MOPCO11
Optical beam loss monitor installed at the SPS slow extraction region
86
An optical beam loss monitor (oBLM) has recently been installed at the slow extraction region of the Super Proton Synchrotron (SPS) at CERN. The oBLM offers a new method for detecting beam losses at the SPS by utilizing the Cherenkov radiation emitted during beam loss interactions with an optical fibre. This setup should allow to measure losses continuously over a large section of the accelerator, thus minimising the non-linearities caused by the finite coverage of the currently installed ionisation chambers. Due to the high radiation levels and low expected signals at this location, special care was taken during the procurement process to maximise the signal levels while at the same time extending the lifetime of the system as much as possible. The rationale behind the choice of specific components is discussed, highlighting their advantages compared to other options. Furthermore, initial measurements of beam loss during extraction are presented, and the system’s ability to provide real-time diagnostics for beam protection and machine optimization investigated.
Paper: MOPCO11
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-MOPCO11
About: Received: 03 Sep 2025 — Revised: 05 Sep 2025 — Accepted: 08 Sep 2025 — Issue date: 20 Jan 2026
MOPCO12
First beam commissioning experience with RF system on chip based bunch by bunch signal processing systems at SLS 2.0 at SLS 2.0
90
After a dark time of 15 months, the new diffraction limited storage ring SLS 2.0 had first beam in January 2025. In April 2025, the nominal beam current of 400 mA was reached. In this contribution, we present the status and first beam commissioning experience with the RF System-on-Chip (RFSoC) based signal processing systems of the new SLS 2.0 ring. RFSoCs integrate several fast multi-GSample/s ADCs and DACs, FPGA (programmable logic) fabric and multi-core CPUs all on the same chip. During SLS 2.0 commissioning, the integrated EPICS IOC of the RFSoCs provided bunch-by-bunch diagnostics of dedicated BPM position and charge readings. Integrated DACs are driving newly developed transverse and longitudinal kicker magnets, enabling bunch-by-bunch excitation and damping. Bidirectional multi-Gigabit fiber optic links connect the RFSoC to the event system master, thus enabling both synchronisation of the RFSoC to the event system, as well as real-time control of the event system master by the RFSoCs, e.g. for control of beam injection timing and filling pattern.
Paper: MOPCO12
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-MOPCO12
About: Received: 06 Sep 2025 — Revised: 08 Sep 2025 — Accepted: 08 Sep 2025 — Issue date: 20 Jan 2026
MOPCO15
Physics-guided data expansion for photocathodes using TESS transverse momentum measurements
101
Precise characterisation of photocathode mean transverse energy is critical for optimising electron beam quality. This paper presents a physics-informed image processing pipeline using Transverse Energy Spread Spectrometer data (231–291 nm), incorporating Gaussian PSF fitting, Wiener deconvolution, resolution equalisation, and noise-aware augmentation. A high-fidelity dataset of 6500 synthetic images was generated, achieving average SSIM = 0.997 and $ R^2 \approx 0.98 $, enabling robust MTE prediction and supporting future ML-based diagnostics for next-generation photoinjectors.
Paper: MOPCO15
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-MOPCO15
About: Received: 03 Sep 2025 — Revised: 08 Sep 2025 — Accepted: 08 Sep 2025 — Issue date: 20 Jan 2026
MOPCO24
Advancements in Cherenkov fiber-based machine protection system at TRIUMF’s e-Linac
124
A Cherenkov fiber-based shut-off system is being developed for TRIUMF’s ARIEL e-Linac to provide a scalable, cost-effective solution for monitoring beam losses in high-radiation environments. The system uses a single 100m long thin silica fiber with photomultiplier tubes at both ends, allowing sensitive electronics to be located outside the radiation area. This design is favorable over bulky ionization chambers and more expensive scintillation-based detectors, as it improves and simplifies deployment in complex environments, particularly the ARIEL beamline tunnel. The prototype demonstrates sub-10 µs response times and position-sensitive detection via the time delay between upstream and downstream signals. Ongoing work focuses on the achievable spatial resolution, the integration into ARIEL’s operations control environment and the systematic evaluation of reliability and sensitivity.
Paper: MOPCO24
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-MOPCO24
About: Received: 03 Sep 2025 — Revised: 22 Sep 2025 — Accepted: 25 Sep 2025 — Issue date: 20 Jan 2026
MOPCO28
Web Streaming Integration for the TLS Beam Size Monitoring Broadcast System
132
The beam size monitor broadcast system at the Taiwan Light Source (TLS) has traditionally used analog coaxial cables and modulators to transmit measurement images and data to control rooms and beamline stations via televisions and tuners. While simple and network-independent, this setup suffers from low resolution, frequent interference, and aging hardware with no ongoing maintenance. This paper presents a lightweight, non-intrusive upgrade that replaces the legacy system with a web-based real-time streaming solution. By capturing the existing output from the measurement system and streaming it using standard web technologies, users can access beam size visuals on any browser-enabled device, gaining better image quality and improved stability while eliminating traditional broadcast maintenance. As TLS is scheduled to be decommissioned in 2027, this solution offers a fast, low-risk, and cost-effective modernization path without altering existing instruments or computing environments. The system is currently under testing, and this paper describes its architecture, implementation, and preliminary results.
Paper: MOPCO28
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-MOPCO28
About: Received: 27 Aug 2025 — Revised: 06 Sep 2025 — Accepted: 10 Sep 2025 — Issue date: 20 Jan 2026
MOPCO31
Development of BPM electronics for PIP-II at Fermilab
139
PIP-II (Proton Improvement Plan-II) is a critical upgrade to the Fermilab accelerator complex. The 800 MeV superconducting linear accelerator will utilize 126 beam position monitors (BPMs) across the Warm Front End (WFE), superconducting linac (SC LINAC), and Beam Transfer Line (BTL). These BPMs provide beam position, phase, timing, and intensity data, meeting stringent physics requirements: 10 µm position resolution, 0.1 mm position accuracy, 1% intensity resolution, 0.3° phase resolution, and 1° phase stability. This paper presents the uTCA4.0-based BPM electronics system. Each AMC with an RTM processes eight signals from two BPMs, with a 12-slot uTCA chassis supporting up to 24 BPMs. The system features 8-channel 250 MSPS ADCs and a Xilinx UltraScale+ SoC FPGA running Linux, facilitating high-speed data transfer via 10 Gigabit Ethernet. Key design aspects include analog signal conditioning, JESD204B routing, clock distribution, and thermal management. FPGA handles BPM signal processing, time tag, digital down-conversion, and phase drift compensation. Performance benchmarks, including position, phase resolution and temperature stability, are validated through dedicated testing.
Paper: MOPCO31
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-MOPCO31
About: Received: 22 Aug 2025 — Revised: 06 Sep 2025 — Accepted: 06 Sep 2025 — Issue date: 20 Jan 2026
MOPCO34
Development of BPM Electronics for Korean 4th Generation Storage Ring
148
New BPM electronics have been developed for installation in the storage ring of the 4th Generation Synchrotron Radiation Facility in Ochang, South Korea. Based on the first prototype, two different platforms were utilized for the development of the second prototype. The first version employs an RFSoC-based design, which acquires broadband signals up to 2 GHz using a high-performance 2.5 GS/s ADC, enabling real-time turn-by-turn data measurement. The second version is implemented using a commercial uTCA board along with a newly developed RTM card designed specifically for BPM electronics. This uTCA-based system utilizes a 500 MHz center frequency with a ±10 MHz narrowband AFE RTM card and a 250 MS/s ADC to perform turn-by-turn data acquisition. This paper presents detailed hardware specifications and configurations and provides an in-depth analysis of beam test results conducted at PLS-II.
Paper: MOPCO34
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-MOPCO34
About: Received: 07 Sep 2025 — Revised: 08 Sep 2025 — Accepted: 10 Sep 2025 — Issue date: 20 Jan 2026
MOPCO36
Application of convolutional neural networks for pile up correction in single particle counting
152
An exploration into the application of machine learning (ML) approaches to identify pile-ups and correct them in single particle counters at the GSI Helmholtz Centre for Heavy Ion Research in presented. About 100000 particle pulse data from various spills were manually labelled and a convolutional neural network (CNN) was developed to accurately count the number of particles without domain-specific knowledge. This contribution represents proof-of-work for a fast error free automated particle counting system. The identified algorithm was developed with a perspective of implementation into an FPGA.
Paper: MOPCO36
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-MOPCO36
About: Received: 01 Sep 2025 — Revised: 07 Sep 2025 — Accepted: 07 Sep 2025 — Issue date: 20 Jan 2026
MOPCO40
Design of digital acquisition for beam current monitor
156
As a part of the Proton Improvement Plan – II (PIP-II) at Fermilab, instrumentation systems are being modernized to take advantage of the higher speeds and ease of use offered by standardized embedded systems like MicroTCA. A rear-transition module (RTM) is being designed to interface with said embedded systems. In each of the four identical channels on the RTM, the differential signal from an alternating-current current transformer (ACCT) transimpedance amplifier will again be amplified by a differential operation-amplifier, then filtered by a low-pass topology. The conditioned signal is then digitized at a maximum of 10MS/s by an analog to digital converter (ADC) integrated circuit. After digitization, the ADC passes the data to an off the shelf AdvancedMC (AMC) Xilinx FPGA module using low voltage differential signals. This paper will describe the simulation of analog circuitry for signal conditioning, simulation of digital signal integrity based on physical design as well as verification of design characteristics critical to signal integrity. This work aims to create a methodology that can be applied to future RTMs requiring application of high-speed digital design principles.
Paper: MOPCO40
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-MOPCO40
About: Received: 29 Aug 2025 — Revised: 05 Sep 2025 — Accepted: 06 Sep 2025 — Issue date: 20 Jan 2026
MOPMO01
Bunch-by-bunch beam current and lifetime measurement with interleaved sampling at HLS
159
To achieve high-precision, bunch-by-bunch beam cur-rent and lifetime measurements at the Hefei Light Source (HLS), we developed a beam diagnostics system based on interleaved sampling technology, achieving an equivalent sampling rate of 6.5 GHz. In single-bunch mode, amplitude extraction via cross-correlation with a single response function yieds a turn-by-turn current relative resolution of 0.12%. By averaging over 200 turns, the resolution is improved to 0.04% at a 23 kHz data refresh rate, enabling fast and accurate lifetime calculations. However, in multi-bunch high-current mode, large longitudinal oscillations degrade the accura-cy of amplitude extraction when using a fixed-response function. We propose an integration method to mitigate the effects of bunch length and phase oscillations on beam current measurements. The method and experi-mental results provide a practical solution for machines exhibiting large longitudinal oscillations, such as HLS.
Paper: MOPMO01
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-MOPMO01
About: Received: 01 Sep 2025 — Revised: 07 Sep 2025 — Accepted: 10 Sep 2025 — Issue date: 20 Jan 2026
MOPMO09
Robotic solution for BLM detector maintenance in high radiation areas
189
CERN’s Beam Loss Monitoring (BLM) system is essential for the protection of machine elements against energy deposition due to beam losses. The protection function relies on approximately 5000 ionisation chamber type detectors installed along all of CERN's accelerators. Some of the areas where the detectors are installed have a high background dose (above 2mSv/h). Installation and maintenance times must be minimised to ensure person-nel safety. For this reason, a new solution was designed that allows the manipulation of detectors and their sup-ports by robotic action. Every aspect of the solution has been designed to reduce intervention time, using a rapid locking mechanism and the possibility of transporting the material by robot. The paper presents the design, prototype characterisation results, identified issues, and mitigation methods developed for the automated manipulation of these detectors.
Paper: MOPMO09
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-MOPMO09
About: Received: 01 Sep 2025 — Revised: 08 Sep 2025 — Accepted: 08 Sep 2025 — Issue date: 20 Jan 2026
MOPMO10
Performance of the Cryogenic Beam Loss Monitors Developed at the LHC
192
Several systems protect the superconducting magnets of the Large Hadron Collider (LHC), which operate at -271.3C. The Beam Loss Monitoring (BLM) system is critical for detecting lost particles around the machine and reacting on their quantity and associated energy. It protects the machine from quenching and irreversible damage. To measure these losses, various detectors are used, primarily ionisation chambers (IC), but also other types of monitors depending on loss intensity. In injection and extraction areas, additional fast polycrystalline Chemical Vapor Deposition (pCVD) diamond detectors measure time structured losses. To increase sensitivity, a new detector, the cryogenic Beam Loss Monitor (CryoBLM), based on pCVD, was developed. It is mounted inside the cryostat between two superconducting magnets in the vicinity of the beam pipes and operates at cryogenic temperatures. Two CryoBLM locations in the LHC target different loss scenarios: betatron halo cleaning and luminosity losses from the CMS physics debris. This contribution presents the CryoBLM performance and comparisons with other detectors.
Paper: MOPMO10
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-MOPMO10
About: Received: 03 Sep 2025 — Revised: 10 Sep 2025 — Accepted: 11 Sep 2025 — Issue date: 20 Jan 2026
MOPMO11
Machine vision cameras for beam spot analysis
196
The Canadian Light Source is a third generation synchrotron which supports 22 operational beamlines. A project to replace all beam diagnostic analog cameras with CCD cameras was initiated in 2020. Over time this project has been expanded to include beam analysis capabilities. We present an EPICS-based imaging system that uses inexpensive CCD cameras. The system computes beam parameters including strength, centroid, ellipticity, eccentricity, and angle. Analysis is performed in real time, and images can also be saved for post processing. Features, implementation details, obstacles and long term plans will be discussed.
Paper: MOPMO11
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-MOPMO11
About: Received: 02 Sep 2025 — Revised: 05 Sep 2025 — Accepted: 06 Sep 2025 — Issue date: 20 Jan 2026
MOPMO13
Intelligent Retrieval Systems for Accelerator Physics: Matching Retrieval Approaches to Use Cases
204
Accelerator facilities generate diverse documentation, from technical reports to structured wikis and semi-structured logbooks, which complicates efficient knowledge access. While Retrieval-Augmented Generation (RAG) offers a path toward intelligent operator assistants, no single method is universally optimal. We present three use cases from PSI: for technical documentation, naive dense retrieval with summarization provides fast and interpretable access; for the AcceleratorWiki, a graph-augmented approach improves reasoning over hierarchies and cross-references; and for ELOG, an agentic pipeline with specialized agents supports multimodal interpretation, temporal reasoning, and iterative refinement. Together, these case studies illustrate how matching retrieval paradigms to data types enables reliable, context-aware assistance in accelerator operations.
Paper: MOPMO13
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-MOPMO13
About: Received: 08 Sep 2025 — Revised: 09 Sep 2025 — Accepted: 10 Sep 2025 — Issue date: 20 Jan 2026
MOPMO15
Beam Instrumentation for the new linear accelerator at the Canadian Light Source
212
The Canadian Light Source (CLS) linear accelerator (linac) serves as the injector for the 2.9 GeV synchrotron. The original linac, which was installed in the 1960's, was replaced in 2024. The new 3000.24 MHz linac was designed and built by RI Research Instruments GmbH. The linac makes use of a 90 kV thermionic source, three 5m long accelerating S-band structures and a SLED pulse compressor system to accelerate electrons to 250 MeV. The initial beam instrumentation included a faraday cup, yag screens, beam position monitors and fast current transformers. During the course of commissioning directional couplers and microphones were added to provide insight into the location of RF breakdowns. This paper will provide an overview of the new linear accelerator and our experience commissioning the new equipment.
Paper: MOPMO15
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-MOPMO15
About: Received: 03 Sep 2025 — Revised: 08 Sep 2025 — Accepted: 11 Sep 2025 — Issue date: 20 Jan 2026
MOPMO16
Joint analysis of beam loss and beam position during the injection process at Hefei light source
215
The Hefei Light Source is a synchrotron radiation facility operating in the vacuum ultraviolet and soft X-ray regions. If the evolution of beam parameters and beam loss during the injection transient process can be observed synchronously, analyzing their correlation can provide more quantitative guidance for further optimizing the injection process. To achieve this goal, a monitoring system capable of synchronously capturing the 3D position of each bunch and rapid beam loss has been established at the Hefei Light Source. Experiments investigated both TOP-UP injection and empty-ring injection processes. Thanks to the unique multi-parameter synchronous diagnosis capability of this system, some previously unnoticed special phenomena have been captured, and a deeper analysis of the correlation between bunch parameters can be conducted. TOP-UP mode exhibited maximum beam loss in the injected bunch, with secondary losses at the 14th subsequent bunch. Peak beam loss occurred immediately after injection in both modes, followed by rapid attenuation within several turns. Loss resurgence appeared after ~85 turns (TOP-UP) or 180 turns (empty ring), followed by oscillatory decay.
Paper: MOPMO16
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-MOPMO16
About: Received: 31 Aug 2025 — Revised: 07 Sep 2025 — Accepted: 09 Sep 2025 — Issue date: 20 Jan 2026
MOPMO21
Beam diagnostic signal processor for SHINE
227
SHINE has developed different signal processors for beam diagnostics, including processors for cold button beam position monitor (BPM), stripline BPM, chicane BPM, cavity BPM, cavity bunch arrival-time monitor (BAM), electro-optic BAM, CSR bunch length monitor (BLM), beam charge loss monitoring, and fast orbit feed-back system (FOFB). The processors employ a common SoC-FPGA-based digital motherboard and accommo-dates diverse applications by hosting various daughter-boards. This paper presents the design of these processors and the applications on SHINE.
Paper: MOPMO21
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-MOPMO21
About: Received: 03 Sep 2025 — Revised: 10 Sep 2025 — Accepted: 17 Sep 2025 — Issue date: 20 Jan 2026
MOPMO22
Upgrade of the BPM processor for SXFEL
231
The Shanghai Soft X-ray Free Electron Laser (SXFEL) is scheduled for a digital and intelligent upgrade over the next two years, aiming to achieve fully autonomous operation. This upgrade requires timestamping the BPM measurement results in the beam diagnostics system to enable synchronous acquisition of all measurement data at SXFEL. A new prototype of the digital BPM signal processor (DBPM) has been developed based on a Zynq UltraScale+ MPSoC FPGA. In addition to high-speed data connectors for the ADC board, the design features an FMC slot to accommodate a White Rabbit timing board for receiving bunch ID and trigger signals as timestamps. It also includes 10 GB SFP ports to support high-speed data transmission between processors. In this paper, the design of the hardware, firmware, and software of the upgraded BPM signal processor is presented.
Paper: MOPMO22
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-MOPMO22
About: Received: 03 Sep 2025 — Revised: 10 Sep 2025 — Accepted: 10 Sep 2025 — Issue date: 20 Jan 2026
MOPMO34
Performance Validation of High-Gradient X-Band Structures at the University of Melbourne’s X-LAB
260
The X-band Laboratory for Accelerators and Beams (X-LAB) at the University of Melbourne enables high-power testing of X-band accelerator technologies, including components for CERN’s Compact Linear Collider (CLIC). At its core is Mel-BOX, a high-gradient test stand rebuilt from CERN’s XBOX3. Two TD24 structures, previously conditioned at CERN, have been successfully re-tested, along with RF windows, SLED-I pulse compressors, and 3D-printed loads. Beam instrumentation at X-LAB includes Faraday cups with high-resolution digitizers to measure dark current and breakdown emissions. Fast time-domain measurements along the waveguide using GHz-bandwidth oscilloscopes allow localization of breakdown events. Optical fibers detect Cherenkov light near the structures, providing complementary pulse-resolved signals. These are cross-referenced with Faraday cup data to study early-stage field emission. X-LAB integrates RF testing and diagnostics to support the development of compact, high-gradient accelerator systems.
Paper: MOPMO34
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-MOPMO34
About: Received: 03 Sep 2025 — Revised: 08 Sep 2025 — Accepted: 10 Sep 2025 — Issue date: 20 Jan 2026
MOPMO35
Measurements of Dark Current and Breakdown Processes using Faraday Cups and Fast Digitisers at the XBand Laboratory for Accelerators and Beams (XLAB)
264
Two CLIC TD24 accelerating structures, manufactured by CERN, are undergoing high-power testing on the 12 GHz RF test stand, MelBOX, at the x-Band Laboratory for Accelerators and Beams (XLAB). Installed in late 2024, these are the first devices tested at the facility. The goal is to condition the structures for stable operation at gradients of 100 MV/m. The maximum gradient is limited by electrical breakdown—vacuum arc formation under high electric fields—which interrupts RF transmission and can damage the structure. To study breakdown dynamics and validate models of their initiation, detailed, time-resolved charge measurements are needed. Faraday cups upstream and downstream, combined with high-performance 5 GS/s, 12-bit, 3 GHz FEB digitisers, enable precise characterisation of both dark and breakdown current emissions. Fast digitiser readout allows continuous acquisition at the 400 Hz repetition rate, capturing breakdown events and several hundred preceding pulses. This dataset supports in-depth analysis of precursors. We present initial results from structure conditioning, including breakdown statistics, dark current trends, and preliminary analysis of breakdown behaviour.
Paper: MOPMO35
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-MOPMO35
About: Received: 03 Sep 2025 — Revised: 10 Sep 2025 — Accepted: 10 Sep 2025 — Issue date: 20 Jan 2026
MOPMO37
Development of CMOS beam loss monitor for Korea-4GSR
271
The beam loss monitor (BLM) is a diagnostic system designed to protect accelerator components from unexpected high-energy radiation. We have developed a cost-effective BLM system for the next-generation synchrotron light source, Korea-4GSR. The system uses plastic scintillators, optical fibers, and a CMOS camera to localize beam losses with 10 ms time resolution. Scintillators placed along the beam-line emit blue light proportional to the ionization energy deposited by beam losses. The light is transmitted through optical fibers, bundled into a 2D array, and imaged by a CMOS sensor at 100 Hz. The BLM’s sensitivity and calibration were verified using a 2 MBq Co-60 gamma-ray source. The preliminary result shows ~45 counts/GeV. Energy deposition was estimated using Geant4 simulations, and photon-to-count conversion was characterized with a calibrated LED source. The DAQ includes a built-in LED pulser for in-situ calibration of the CMOS detector and cable integrity check. This presentation outlines the system design, calibration methods, and performance results.
Paper: MOPMO37
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-MOPMO37
About: Received: 07 Sep 2025 — Revised: 08 Sep 2025 — Accepted: 10 Sep 2025 — Issue date: 20 Jan 2026
MOPMO39
Development of wall current monitor on FETS-FFA test ring
278
Conceptual design studies of the FETS-FFA demonstration ring have been actively performed to confirm the reliability of a Fixed Field Alternating gradient (FFA) accelerator for a future high-power spallation neutron source, called ISIS-II. A wall Current Monitor (WCM) is a choice of non-destructive intensity monitor to evaluate the circulating proton beams from 3 MeV (about 1MHz in revolution frequency) to 12 MeV(about 2MHz in revolution frequency) in the FETS-FFA test ring. As the beam orbit shifts radially with beam energy in FFAs, the aperture of FETS-FFA WCM will be about 700mm horizontally. The maximum mean circulating beam current is about 100mA and tomographic and Schottky measurements require a bandwidth of 370MHz (100 harmonics). This is a challenge for such a large monitor. A half-width demonstration WCM (demo-WCM) was designed and manufactured to benchmark numerical simulations and to understand monitor responses. Whilst measured frequency band was lower than expected, 1% intensity resolution was achieved in the demo-WCM. In this paper, the detail design study as well as the signal response of the demo-WCM will be presented.
Paper: MOPMO39
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-MOPMO39
About: Received: 30 Aug 2025 — Revised: 06 Sep 2025 — Accepted: 07 Sep 2025 — Issue date: 20 Jan 2026
MOPMO43
Beam loss measurements during Injection into the Advanced Photon Source Upgrade storage ring
290
A fiber-optic (FO) beam loss montior (BLM) system, installed along the booster to storage ring (BTS) trasnport line has been useful in identifying loss locations employing time-of-flight (TOF) analysis. The BTS BLM TOF system is comprised of a pair of rad-hard, fused-silica FO cables running along either side of the BTS line at beam elevation. In the initial configuration, we measured losses at both the upstream (US) and downstream (DS) ends of the FO cable pair. However, losses further DS along the septum and injection kicker set are also of interest. We therefore added a 20-m-length, multi-strand fused-silica FO cable bundle, replacing the DS outer FO radiator input. Thus, three of the detectors are configured at the US end of their respective FO radiators. The US detector location provides lower signal but improved spatial resolution over the DS. Loss location identification has been accomplished by inserting YAG screen flags at different positions along the BTS. We present results from studies and operations.
Paper: MOPMO43
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-MOPMO43
About: Received: 28 Aug 2025 — Revised: 07 Sep 2025 — Accepted: 07 Sep 2025 — Issue date: 20 Jan 2026
MOPMO45
Fermilab PIP-II machine protection system digitized data noise elimination scheme and its FPGA implementation
294
In Fermilab's PIP-II machine protection system, beam loss signals from various detectors are digitized at 125 MS/s. Noise from both high-frequency sources and low-frequency 60 Hz AC power equipment can contaminate the data. To suppress noise across these ranges—especially 60 Hz and its harmonics, which overlap with beam loss signal frequencies—advanced digital processing beyond standard filtering is required. Several real-time functional blocks were simulated and tested on an FPGA: (1) a dual time-constant discharging integrator filter, (2) a de-ripple baseline extraction and storage block, and (3) a fast-recovery discharging integrator. The nonlinear IIR integrator filter removes high-frequency noise and feeds into the baseline extractor. Upon detecting abrupt beam loss, it switches to a longer time constant to prevent baseline distortion. The de-ripple block calculates a valid baseline by averaging over multiple 60 Hz periods, storing results in a 4096-word FPGA RAM. This baseline is subtracted from raw data before integration by the fast-recovery block, which resets quickly after use. All blocks achieved expected performance and were successfully implemented on a low-cost FPGA.
Paper: MOPMO45
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-MOPMO45
About: Received: 30 Aug 2025 — Revised: 09 Sep 2025 — Accepted: 10 Sep 2025 — Issue date: 20 Jan 2026
TUAI01
High-throughput DPDK-based framework for real-time applications in Elettra 2.0
297
The Data Plane Development Kit (DPDK) is a framework that enhances real-time communications by providing direct, high-speed access to network interfaces. This architecture centralizes acquisition and control in an HPC cluster, ensuring ultra-fast in-memory updates of all critical data, making it a viable choice for real-time feedback and machine control in particle accelerators. This approach was chosen for Elettra 2.0 to enable pre-mortem beam dump mitigation, more detailed post-mortem inspection, advanced correlation analysis and the implementation of complex control schemes. Time-sensitive applications implemented in C code interact with Beam Position Monitors (BPM), Low-Level RF (LLRF), Beam Loss Monitors (BLM) and Magnetic Power Converters through simple memory read and write operations at megahertz rates, making the system competitive with high-level processing applications based on FPGA architectures. This paper presents the system under test at Elettra, highlighting its architecture, performance, and integration, while demonstrating the successful implementation of Fast Orbit Feedback in parallel with turn-by-turn (TbT) data acquisition from twelve BPMs and an LLRF system.
Paper: TUAI01
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-TUAI01
About: Received: 30 Aug 2025 — Revised: 04 Sep 2025 — Accepted: 10 Sep 2025 — Issue date: 20 Jan 2026
TUBC01
Isolating the light of a single bunch: determining the viability of operating vertical-plane Pulse Picking by Resonant Excitation at Diamond-II to serve timing mode users
308
Pulse Picking by Resonant Excitation (PPRE) enables synchrotron facilities to provide single-bunch light for timing users without interrupting multi-bunch operation*. We report the first vertical-plane PPRE tests at Diamond using the Multi-Bunch Feedback system, achieving vertical bunch-size growth and measurable X-ray enlargement. A simple novel optimisation improved PPRE purity by reducing the baseline emittance. Beyond readily-available diagnostics, we demonstrate how crystallographic diffraction can be used as a user-relevant method to characterise PPRE with statistically significant evidence of isolating a single excited bunch. Together, these methods provide a practical and user-orientated framework for synchrotron facilities considering similar timing-mode capabilities.
Paper: TUBC01
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-TUBC01
About: Received: 04 Sep 2025 — Revised: 07 Sep 2025 — Accepted: 10 Sep 2025 — Issue date: 20 Jan 2026
TUDI01
A review of space charge compensation diagnostics
328
The space charge of high-intensity ion beams makes it challenging to transport the beam through the LEBT and inject it into the subsequent accelerator. Space charge compensation (SCC) is a process that lowers the space charge of an ion beam by trapping either positive ions or electrons, created by interaction of the beam with residual gas. The compensating secondary particles reduce the beam potential and the space charge-induced divergence of the beam. Significant beam losses during SCC build-up necessitate minimising the SCC time of pulsed high-current ion beams. To address this, diagnostics techniques are used to study the SCC process and measure its degree or time. These techniques include emittance meters, beam profile monitors, wire scanners, retarding field analysers, and optical sensors. Such diagnostics are applicable to positive and negative ion beams, with unique challenges based on the specific ion beam and residual gas used. In this paper we review common SCC diagnostic techniques, discuss the differences in SCC diagnostics for continuous and pulsed beams as well as positive and negative beams, and highlight the importance of supporting particle-in-cell simulations.
Paper: TUDI01
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-TUDI01
About: Received: 03 Sep 2025 — Revised: 04 Sep 2025 — Accepted: 06 Sep 2025 — Issue date: 20 Jan 2026
TUPCO07
Reconstruct transverse initial conditions of high intensity beams using machine learning
358
Space charge effect was considered a driving force for emittance growth in high-intensity beams. To understand it, the emittance needs to be measured. In the past, the quadruple scan was one of the simple and efficient methods to measure beam emittance, but it is difficult to apply to high-intensity beams where the space charge plays a dominant role due to the deviation from the quadratic fitting. The tomography method was used before for this case to reconstruct phase space and then obtain the emittance, but the scan was time-consuming, and the post-analysis was very complex. One of the solutions is to use the genetic algorithm and treat this as an optimisation problem where the emittance needs to be optimised for the beam to match the quadruple scans. This method also involves heavy post-analysis, which limits its online application. In this contribution, machine learning methods will be used to reconstruct the phase space based on PIC simulations of space charge-dominated beams. of effectiveness of the machine learning method against the space charge level will be studied.
Paper: TUPCO07
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-TUPCO07
About: Received: 03 Sep 2025 — Revised: 07 Sep 2025 — Accepted: 07 Sep 2025 — Issue date: 20 Jan 2026
TUPCO08
Status of longitudinal instability suppression at NanoTerasu
362
NanoTerasu is a 3 GeV light source newly constructed in Sendai, Japan. The circumference is 349 m and the natural emittance is 1.1 nm rad, which is realized by a double-double-bend achromat lattice. The commissioning of the storage ring started in June 2023. The longitudinal instability was observed when the stored beam current reached 150 mA in August 2023. The temperature of RF cavity was adjusted to suppress the instability. The user operation was started on schedule in April 2024 with a stored beam current of 160 mA. The stored beam current was reached 200 mA without the beam instability in July 2024. The stored beam current at user operation period was limited to 200 mA by the longitudinal instability. We try to suppress the longitudinal beam instability using several methods. We developed the pillbox type RF kicker cavity to suppress the instability. In addition, we tried to suppress the longitudinal instability using the transverse feedback kicker. I will report the status of longitudinal instability suppression at NanoTerasu.
Paper: TUPCO08
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-TUPCO08
About: Received: 27 Aug 2025 — Revised: 08 Sep 2025 — Accepted: 10 Sep 2025 — Issue date: 20 Jan 2026
TUPCO09
Side effects of bunch-by-bunch feedback system on SuperKEKB collider
366
The bunch-by-bunch feedback system is now an key function in high-current, multi-bunch storage rings to suppress coupled-bunch instability and/or to reduce the effects of injection vibration. In high-luminosity e+e- colliders such as SuperKEKB, strong beam-beam interactions occur due to collisions, which usually introduce very wide frequency response on the transverse bunch motion far out of the betatron tune. In vertical plane it may cause increase of the beam size which has a large impact on the luminosity. In this presentation, we will present the principle and configuration of our bunch feedback system, the cause of the side effects of the bunch feedback system, and several trials to overcome them.
Paper: TUPCO09
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-TUPCO09
About: Received: 02 Sep 2025 — Revised: 04 Sep 2025 — Accepted: 05 Sep 2025 — Issue date: 20 Jan 2026
TUPCO11
Evaluating machine learning models for multimode-fiber-based transverse beam profile reconstruction
373
Transverse beam profile monitoring is essential for safe and efficient accelerator operation. In high-radiation environments such as beam dumps, cameras degrade rapidly. To address this, a single multimode fiber (MMF) transmission system was previously tested to transport scintillation light from a screen to a remote camera. Because multiple guided modes are excited and coupled during propagation, the fiber output does not preserve the image and requires reconstruction. This contribution evaluates seven machine-learning reconstruction models for recovering the original transverse beam distribution from MMF output. Using data from the MMF-relayed Chromox screen campaign at CERN’s CLEAR facility, the study compares models in terms of reconstruction error, convergence speed, and run-to-run stability, with particular attention to the use of incoherent light. The results indicate robust options for radiation-tolerant, MMF-based transverse diagnostics.
Paper: TUPCO11
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-TUPCO11
About: Received: 03 Sep 2025 — Revised: 05 Sep 2025 — Accepted: 08 Sep 2025 — Issue date: 20 Jan 2026
TUPCO14
Status of oscillating arm wire monitor development
383
We present the development of a high-speed oscillating-arm wire monitor. Similar devices are in use at PSI’s HIPA facility since the 1970s, however they are significantly slower. The new design maintains the compact longitudinal footprint of the original instrument; a property rarely found among fast wire monitors. First performance tests demonstrated wire velocities of 4 m/s using a stepper motor and 8 m/s with a servo motor. This advancement will allow to use wire scanners to measure the beam profile in the most challenging of the HIPA beamlines, with beam current exceeding 10 mA.
Paper: TUPCO14
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-TUPCO14
About: Received: 06 Sep 2025 — Revised: 09 Sep 2025 — Accepted: 10 Sep 2025 — Issue date: 20 Jan 2026
TUPCO18
Experimental investigation into supersonic gas jet induced beam perturbation
399
In radiotherapy, treatment beams require precise margins to ensure the preservation of surrounding healthy tissue. Clinical studies have shown that to mitigate range deviations of the Bragg peak, safety margins of typically less than 5\% around the target volume are employed. Consequently, real-time or online diagnostic techniques should be designed to minimize beam perturbation to the greatest extent possible. A minimally-invasive gas jet beam profile monitor for medical treatment facilities is being developed at the Cockcroft Institute (UK) to provide online monitoring. The monitor operates a thin, low-density, gas jet curtain, transecting with the beam. A proof-of-concept experimental study was carried out to quantify the degree of perturbation the gas jet has on a beam, using a 10 keV electron gun with a maximum current of ~100 μA. Any changes in beam profile and current were measured via a scintillator screen and Faraday cup respectively in path of the beam after the gas curtain. In the future, a simulation study will also be carried out using BDSIM, a Beam Delivery Simulation program built on GEANT4, with the experimental beam parameters along with medical hadron beams. This contribution provides the details of an experimental study into the perturbation experienced by an electron beam from a gas jet monitor.
Paper: TUPCO18
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-TUPCO18
About: Received: 01 Sep 2025 — Revised: 06 Sep 2025 — Accepted: 08 Sep 2025 — Issue date: 20 Jan 2026
TUPCO29
Real-time embedded feedforward correction for SIRIUS undulators
428
SIRIUS, the Brazilian 4th generation synchrotron light source, has been in operation since 2020. Over time, insertion devices (IDs) are expected to populate its straight sections. To supress edge effects from undulators and support overall beam stability, a feedforward correction system is currently available through EPICS layer for the first installed ID. However, performance could be improved by adopting a lower-level solution with higher actuation rates and reduced jitter. To address this, a new approach has been developed using hardware technology already available: control system nodes based on BeagleBone Black platform, which integrates both embedded linux and dedicated real-time processors within the same SoC. This setup enables current setpoints updates at rates up to 1 kHz and aiming to be scalable. This paper presents an overview of the system's architecture and objectives, first results with IVU and VPU undulators as well as future developments and improvements.
Paper: TUPCO29
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-TUPCO29
About: Received: 03 Sep 2025 — Revised: 11 Sep 2025 — Accepted: 11 Sep 2025 — Issue date: 20 Jan 2026
TUPMO05
Gas-Jet based Ionization Profile Monitor for Proton FLASH Therapy
460
In proton FLASH therapy the beam monitoring is crucial to ensure the conformal dose deposition to the tumour and effective Organ at Risk (OAR) sparing. A non- invasive real time beam monitoring improves the efficacy as the dose is delivered in shorter time scales. To achieve this, gas-jet based Ionization Profile Monitor (IPM) is developed with potential capability towards real time beam monitoring. It detects ions produced by the interaction of primary beam with a thin (<1 mm) gas-curtain without perturbing the beam. This work presents the simulation of IPM to study the ion extraction under different configuration for accurate reconstruction of the beam shape. The role of electric field in the IPM on the trajectory of the ions and the inhomogeneity in their energy distribution affecting the beam profile are studied. The study also investigates the effect of beam misalignment, relative contribution of individual ion states generated due to interaction, and the gas-curtain density distribution. Future work will address configuration required to accommodate broader range of beam relevant to clinical application.
Paper: TUPMO05
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-TUPMO05
About: Received: 02 Sep 2025 — Revised: 10 Sep 2025 — Accepted: 10 Sep 2025 — Issue date: 20 Jan 2026
TUPMO07
Beam size measurement at SBL in SuperKEKB
467
Sudden beam loss (SBL) is one of the obstacles to improving the luminosity of SuperKEKB. SBL cause damage to collimators and other accelerator components, QCS quench, and large background to the Belle II detector. It also causes beam abort and prevents the accumulation of high currents. Therefore, it is an important issue to investigate and resolve the causes of SBL events. In order to investigate the causes of SBL events, we measured the beam profile at the moment abort due to SBL using three different cameras and found that the beam size was larger than at the moment of abort due to other causes. This paper summarizes the results of the beam size measurements made as part of the investigation into the cause of the SBL.
Paper: TUPMO07
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-TUPMO07
About: Received: 03 Sep 2025 — Revised: 09 Sep 2025 — Accepted: 09 Sep 2025 — Issue date: 20 Jan 2026
TUPMO10
Passive Transverse Beam Profiler for Real-Time Monitoring for FLASH radiotherapy
479
Real-time beam monitoring is essential for enhancing the efficacy and reliability of radiotherapy. FLASH radiotherapy has shown a strong potential in improving treatment effectiveness by delivering doses at ultrahigh dose rates (>40 Gy/s). Beam monitoring at FLASH is challenging, as existing devices like Ionization chambers face saturation. We are developing an all-optical monitor for real-time transverse beam profile measurements in the treatment beam delivery zone. As the therapeutic beam must inherently traverse the ambient air path from the nozzle to the patient, the monitor passively captures beam-induced fluorescence along its trajectory without affecting the beam. This contribution present proof-of-concept measurements with 10.8–28 MeV protons at MC40 Cyclotron at University of Birmingham for 1 to 25 nA beam current, achieving a temporal resolution of up to 10 ms, and compared with beam size measurements with RCF. The fluorescence intensity exhibits a linear response to beam current, suggesting its potential for dose prediction after calibration. This work also discusses the challenges and potential for improvement for FLASH radiotherapy systems.
Paper: TUPMO10
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-TUPMO10
About: Received: 29 Aug 2025 — Revised: 04 Sep 2025 — Accepted: 05 Sep 2025 — Issue date: 20 Jan 2026
TUPMO19
Current status of developing pepper-pot emittance monitor for high-intensity ion beam
505
The experiment to measure the Electric Dipole Moment (EDM) of Francium (Fr) is in progress by Center for Nuclear Study (CNS), UTokyo. Fr is produced via a nuclear fusion reaction by bombarding a gold target with oxygen-18 beam, requiring a beam intensity of 18 eμA or higher. However, the transport efficiency of the current beam line decreases to 66 % when the beam intensity exceeds 10 eμA. To address this issue, we are developing a pepper-pot emittance monitor (PEM) optimized for high-intensity beams. The improvements include locating the camera far from the beam line to minimize radiation damage, achieving a distance 4.1 m while maintaining the position error of 0.13 mm. Additionally, we conducted beam tests to verify measurement errors and found the results were consistent with the measurement errors estimated from the PEM structure. Furthermore, the beam shutter time 0.27 was estimated to be acceptable up to the beam power 1000 W to prevent PEM overheating.
Paper: TUPMO19
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-TUPMO19
About: Received: 03 Sep 2025 — Revised: 06 Sep 2025 — Accepted: 10 Sep 2025 — Issue date: 20 Jan 2026
TUPMO25
Initial implementation of a new orbit feedback system using MicroTCA.4 for the PF user operations
524
A new orbit feedback system has been introduced to the PF-ring, a synchrotron radiation source at KEK, starting from the third operation period of FY2024. The new system is built with state-of-the-art digital signal processing circuits based on the MicroTCA.4 standard. The stored beam’s closed orbit distortion (COD) is measured at a 10 kHz rate using the circuits matched to the number of BPMs, and corrected to a designated reference orbit by feeding back the results of matrix calculations using the inverse response matrix to the currents of fast steering magnets. The transition from the legacy VME-based system, which had been in service for nearly 30 years, was carried out carefully and stepwise during the startup phase of the third operation period. The reference orbit was successfully transferred to the new system, and even in-vacuum undulators with a minimum gap of 4 mm were operated without requiring additional orbit corrections. In this presentation, we will describe the setup of the newly implemented system, the transition process from the old system, and plans for future improvements.
Paper: TUPMO25
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-TUPMO25
About: Received: 03 Sep 2025 — Revised: 04 Sep 2025 — Accepted: 04 Sep 2025 — Issue date: 20 Jan 2026
TUPMO34
Development of white beam profile monitor for Korea-4GSR
550
Accurate measurement of photon beam position and profile is crucial for beamline users to achieve precise alignment and efficient utilization of the desired photon beam. In low-emittance storage rings, however, the power density of the photon beam has increased, making it challenging for conventional profile monitors such as wire scanners and scintillating screens to withstand the high power without damage. Here, we present the development of an Ionization Profile Monitor (IPM) capable of robustly measuring the photon beam position and enabling non-destructive beam profile measurement. A noble gas environment was designed to ensure sufficient ionization signal strength, and a defocusing electrode structure was introduced to fully utilize the relatively large active area of the readout system. Since the magnification induced by the defocusing field depends on the vertical position, we proposed a calibration method to correct for the resulting non-linearity. Finally, we present the results from prototype testing, including the measured position accuracy and the point spread function analysis.
Paper: TUPMO34
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-TUPMO34
About: Received: 08 Sep 2025 — Revised: 09 Sep 2025 — Accepted: 10 Sep 2025 — Issue date: 20 Jan 2026
TUPMO41
Preliminary data analysis of an IPM prototype CSNS RCS
570
In the China Spallation Neutron Source (CSNS), an Ion Profile Monitor (IPM) was installed in the Rapid Cycling Synchrotron (RCS) to address challenges in measuring strong-current beam profiles and enable real-time monitoring. This study focuses on the preliminary analysis of IPM data signals, aiming to accurately extract critical beam information from the signals. Residual gas components in the vacuum chamber were identified through peak spacing calculations. Real-time beam profiles (0–20 ms, low power) were obtained, revealing the beam center and temporal evolution of rms beam size. Fast Fourier Transform (FFT) of signal peaks uncovered dynamic changes in the synchrotron tune. Single- and multi-Gaussian fitting methods were used to analyze MCP-collected charge over time and determine MCP saturation time point. The results demonstrate that IPM data analysis effectively extracts beam information, supporting real-time monitoring and optimization of CSNS RCS beam stability and quality.
Paper: TUPMO41
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-TUPMO41
About: Received: 03 Sep 2025 — Revised: 08 Sep 2025 — Accepted: 11 Sep 2025 — Issue date: 20 Jan 2026
TUPMO42
Results from the new titanium wired harp at the Spallation Neutron Source
574
AA new harp has been installed in the Ring To Target Beam line (RTBT) section of Spallation Neutron Source. The harp is made of two planes with 32 titanium 50 micron wide wires each plane. The narrow, low-Z wires versus the 100-micron tungsten wires of the original harp, are to minimize the beam scattering. This harp will be both a backup and a complement to the existing harp further downstream. The newly created data-acquisition system is also suitable to replace the existing’s harp data-acquisition system, now over 20 years old. We show the use of a cRIO platform as a cost-effective way to process many channels and sample the beam profile at the full 60 Hz beam repetition rate. We also describe the performance of the titanium wires. A passive analog board is used to lengthen the signals to allow sampling at <= 10kS/s/ch. The data is acquired by the FPGA, passed on to the real-time OS, LabVIEW RT, and through the SNS EPICS Channel Access server presented to the control room.
Paper: TUPMO42
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-TUPMO42
About: Received: 03 Sep 2025 — Revised: 10 Sep 2025 — Accepted: 10 Sep 2025 — Issue date: 20 Jan 2026
TUPMO43
Time-resolved measurements of transverse beam excitation in an electron storage ring
578
In the Karlsruhe Research Accelerator (KARA), electron beams of up to 200 mA are stored with an energy of 2.5 GeV, while injection is performed at 500 MeV. At the injection energy, the beam life time and the injection efficiency depend largely on Touschek scattering. As a counter-measure, the beam size can be enlarged transversally by an excitiing modulation, e.g. applied via a strip-line. Here, we examine different excitation strategies and their effects on beam size and the beam orbit. The ultra-fast line camera KALYPSO is used to measure the transverse beam profile via the emitted synchrotron radiation on a turn-by-turn basis.
Paper: TUPMO43
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-TUPMO43
About: Received: 03 Sep 2025 — Revised: 08 Sep 2025 — Accepted: 10 Sep 2025 — Issue date: 20 Jan 2026
WEBC02
Lessons learned in commissioning the new beam-loss monitors for the superconducting upgrade to LCLS
593
The superconducting upgrade to the LCLS x-ray free-electron laser at SLAC is now in commissioning, as we gradually raise the repetition rate of the 4-GeV beam toward 1 MHz and the beam power toward 120 kW. A further upgrade next year will double the energy and power. Machine protection at this extremely high power required a novel system of fast beam-loss monitors (BLMs). Points of concern, such as collimators or kickers, are covered by diamond detectors (PBLMs). Long optical fibres (LBLMs) of up to 200 m span the entire 4-km facility, generating and capturing Cherenkov emission from beam-loss showers. Previous papers have reported on the design and early commissioning of this safety system, and on plans to use the loss signals for wire scanners and loss localisation. Subsequent experience in commissioning and operating the full system has demonstrated that the concept is sound and sensitive, but several aspects of the implementation have proven troublesome. Extensive testing and debugging uncovered issues with both hardware and firmware. We will detail these problems, their remedies, and the improvements in performance.
Paper: WEBC02
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-WEBC02
About: Received: 03 Sep 2025 — Revised: 09 Sep 2025 — Accepted: 09 Sep 2025 — Issue date: 20 Jan 2026
WEBI01
Simultaneous measurements with fast beam size and position monitors disentangle the sudden beam loss evolution mechanism
598
At the SuperKEKB electron-positron collider, which aims to achieve the world's highest luminosity, "Sudden Beam Loss events (SBL)" have prevented its stable operation, in which several tens of percent of the beam current is lost and aborted within several turns (20-50 µs). Elucidating SBLs, which can cause extensive damage to accelerator components and the Belle II experiment detectors, is a pressing issue for SuperKEKB. To measure the beam size and position variation, key information for disentangling SBLs, over dozens of turns just before the SBL-induced beam aborts, we have developed new turn-by-turn beam size monitors in two different wavelength regions, X-ray and visible light, and bunch-by-bunch beam position monitors where one has utilized a novel architecture AMD/Xilinx RFSoC. Simultaneous measurements of turn-by-turn beam size and bunch-by-bunch beam position enable elucidation of the cause and time evolution mechanism of the SBL events. In this presentation, we will first introduce recently developed fast beam size and beam position monitors, then show their simultaneous measurements of SBL events. Finally, we will discuss the possible causes and time evolution mechanisms of the SBL events.
Paper: WEBI01
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-WEBI01
About: Received: 03 Sep 2025 — Revised: 09 Sep 2025 — Accepted: 09 Sep 2025 — Issue date: 20 Jan 2026
WEPCO02
Study of XBPM diagnostic parameters in the TPS frontend
612
The XBPM installed in the TPS frontend determines the center position of the photon beam using four CVD diamond blades. The combination of XBPM and upstream/downstream EBPM readings of the insertion device enables verification of the photon beam’s alignment along the correct trajectory. Significant changes in the beam position or profile, as well as prolonged periods without recalibration, may cause the XBPM measurement data to lose its reliability. Therefore, evaluating the reliability of the XBPM measurement data is of critical importance. By analyzing the deviation between the theoretical and measured blade intensities and calculating the standard deviation of the similarity percentage among the four blades, a reliability indicator is established. The variation of this indicator is analyzed under different conditions and compared with the corresponding Q values.
Paper: WEPCO02
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-WEPCO02
About: Received: 29 Aug 2025 — Revised: 08 Sep 2025 — Accepted: 10 Sep 2025 — Issue date: 20 Jan 2026
WEPCO03
Results of HESR BPM Testing
615
For the HESR diagonally cut BPMs were designed, with 64 manufactured and tested with a purpose-built BPM test-stand. This test-stand had to host BPMs of various lengths, the overall length of the complete vacuum system varies from 450 mm to 1585 mm. For all BPMs several properties, e.g. the geometric factors or the electrical center in relation to the geometric center, were measured utilizing the test stand. The results of these measurements will be presented together with the challenges resulting from the design choices made for the layout of the test stand.
Paper: WEPCO03
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-WEPCO03
About: Received: 06 Sep 2025 — Revised: 10 Sep 2025 — Accepted: 10 Sep 2025 — Issue date: 20 Jan 2026
WEPCO09
Bunch by bunch measurement at the HEPS by oscilloscope
637
By directly sampling the BPM signals with a high sampling rate oscilloscope, the bunch-by-bunch position and phase were calculated. With the help of injection trigger signal, oscilloscope was utilized to capture the injection process. The energy mismatch of the injection transient process and the residual oscillation of the injection bunch were studied. The longitudinal tune and oscillation amplitudes can be inferred. The bunch-by-bunch transverse position and longitudinal phase were analyzed by principal component analysis (PCA). The method also can be used to study the instability of the coupled bunches.
Paper: WEPCO09
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-WEPCO09
About: Received: 03 Sep 2025 — Revised: 10 Sep 2025 — Accepted: 11 Sep 2025 — Issue date: 20 Jan 2026
WEPCO10
Button BPM development and prototyping for ALBA II
641
As part of the ongoing ALBA II upgrade, which aims to significantly enhance the performance of the ALBA Synchrotron Light Source, a new design for button Beam Position Monitors (BPMs) is under investigation. In this contribution, we present the results of a characterization study conducted on button prototypes supplied by two different manufacturers. Furthermore, we introduce the preliminary design of an alternative button BPM intended for direct welding to the copper vacuum chamber of the upgraded machine.
Paper: WEPCO10
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-WEPCO10
About: Received: 02 Sep 2025 — Revised: 08 Sep 2025 — Accepted: 10 Sep 2025 — Issue date: 20 Jan 2026
WEPCO14
Spiral beam position monitor for heavy ion beams
649
Our heavy ion beams are slow, short, and thick. For such beams, spiral beam position monitors(BPMs) are expected to provide good linearity and multiple information readouts despite their small size. At the RIKEN Nishina Center, various ion beams are accelerated using linacs and cyclotrons. However, the beams handled are slow enough compared to relativistic speeds, the bunch length is only about the same as the electrode size, and the beam diameter may be close to the electrode spacing. Conventional “diagonal cut” or “cosine two-theta cut” (for quadratic moments) BPMs produce deviations in wave height*. To solve this problem, it is expected that the wave height deviation can be eliminated by cutting the electrode in a spiral shape. Furthermore, by cutting in a spiral shape, multiple cuts can be placed in one BPM, and it is expected that beam intensity, horizontal position, vertical position, and second moment can be read out at a single location. The performance shown by simulations of the spiral BPM and the development of a prototype will be presented.
Paper: WEPCO14
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-WEPCO14
About: Received: 03 Sep 2025 — Revised: 09 Sep 2025 — Accepted: 10 Sep 2025 — Issue date: 20 Jan 2026
WEPCO22
High-resolution longitudinal beam diagnostics with a Fast Faraday Cup at the UNILAC accelerator
666
At the heavy ion accelerator UNILAC at GSI Helmholtz Center for Heavy Ion Research in Darmstadt, measurements were carried out with a Fast Faraday Cup (FFC) in order to precisely measure the time structure of the particle beam. The FFC offers a highly accurate time-resolved recording of the charge distribution along the longitudinal beam profile. The data obtained in combination with a dipole magnet is used to determine the longitudinal phase space and emittance of the beam. After analyzing the measurement results, the method is integrated into the regular beam diagnostics to ensure continuous monitoring and control of the particle beam during operation. Measurement procedure and results are presented.
Paper: WEPCO22
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-WEPCO22
About: Received: 04 Sep 2025 — Revised: 11 Sep 2025 — Accepted: 11 Sep 2025 — Issue date: 20 Jan 2026
WEPCO23
Recent upgrades of longitudinal diagnostics at FLASH
670
In the framework of the recent FLASH2020+ upgrade program, the longitudinal electron beam diagnostics of the FLASH accelerator had been modernized and extended by additional devices, including an electro-optical bunch length detector (EOD[1]), as well as an additional bunch compression monitor (BCM [2]) and a bunch arrival-time monitor (BAM [3]) in the new direct seeding beamline FLASH1. Also, the THz intensity spectrometer (CRISP [4]) received a modernized control interface that will allow non-experts to perform bunch profile measurements. The paper presents an overview on the current status of the longitudinal electron beam diagnostics at FLASH and the ongoing (re-)commissioning.
Paper: WEPCO23
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-WEPCO23
About: Received: 03 Sep 2025 — Revised: 07 Sep 2025 — Accepted: 11 Sep 2025 — Issue date: 20 Jan 2026
WEPCO28
Measurement of two beams positions with button BPM
687
Modern BPM processors utilize digital processing of the beam induced signals. The information on the signal amplitudes is used for the delta over sum calculation of the beam position, while the readily available phase information is usually discarded. We have experimentally tested measurement of the individual positions of two beams propagating in the common beampipe utilizing both phase and amplitude data. The proposed method can be used for the energy recovery linacs and colliders.
Paper: WEPCO28
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-WEPCO28
About: Received: 14 Aug 2025 — Revised: 07 Sep 2025 — Accepted: 10 Sep 2025 — Issue date: 20 Jan 2026
WEPCO29
Development of analog front-end module for the BPM signal processor at SSRF
690
A new BPM processor is being developed to address the ageing of BPM signal processors and the new demand for synchronised data acquisition at the storage ring of Shanghai Synchrotron Radiation Facility (SSRF). The BPM processor consists primarily of a digital carrier board and an analog front-end (AFE) module. The AFE is responsible for the conditioning of the BPM output RF signal and for the compensation of long-term drift. This paper presents the design of the AFE module and gives an evaluation of its performance. The experimental results show that the AFE module under development fully satisfies the high resolution and high stability requirements of the upgraded SSRF BPM processor.
Paper: WEPCO29
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-WEPCO29
About: Received: 03 Sep 2025 — Revised: 08 Sep 2025 — Accepted: 10 Sep 2025 — Issue date: 20 Jan 2026
WEPCO37
Study of beam position monitors for PERLE
700
PERLE is an Energy-Recovery Linac (ERL) to be constructed at IJCLab in Orsay. It will be the First multi-turn ERL with superconducting RF (SRF) with the ambition to reach 10MW beam operation (20mA beam current and 500MeV beam energy) Diagnostics are a key element for PERLE operation and among diagnostics, the salient feature for Beam position monitors (BPMs) is the presence of multiple beams which need to be individually diagnosed and controlled. This document describes the design and the operation of PERLE BPMs with particular attention given to how these BPMs will handle multiple beams during commissioning and under normal operation of PERLE
Paper: WEPCO37
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-WEPCO37
About: Received: 28 Aug 2025 — Revised: 07 Sep 2025 — Accepted: 09 Sep 2025 — Issue date: 20 Jan 2026
WEPCO40
Fibre-Coupled Oscillator-Driven Electro-Optic Spectral Interferometry as a Longitudinal Bunch Profile Monitor
707
Electro-optic (EO) diagnostics offer non-destructive methods to resolve the longitudinal charge profile of highly relativistic bunches without the need for complex calibrations or ambiguous phase recovery techniques. The most common technique, EO spectral decoding (EOSD), is favoured for its simplicity, reliability, and straightforward output interpretation, however its resolution is constrained to the geometric mean of the transform-limited and chirped probe laser durations. We have introduced a new technique utilising spectral interferometry (EOSI), which overcomes this limitation by adding a single optical element to an EOSD setup, with successful measurements shown previously on the CLARA accelerator at Daresbury Laboratory. To further explore this technique, we have performed EOSI on the CLEAR accelerator at CERN (160-200 MeV, 15-150 pC and 0.2-1.5 ps RMS) utilising a nJ oscillator and optical fibre-coupled transport. Our results highlight the potential for low power, turn-key operation and flexible integration of EOSI systems for single-shot ultrashort bunch length and arrival time monitoring.
Paper: WEPCO40
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-WEPCO40
About: Received: 03 Sep 2025 — Revised: 07 Sep 2025 — Accepted: 11 Sep 2025 — Issue date: 20 Jan 2026
WEPMO12
Digital signal processing improvements of the SPIRAL2 beam position monitors at low intensity
743
The SPIRAL2 accelerator, designed for high intensity beams (up to 5 mA), needs to evolve for low intensities in order to reach the requirements of the S3 experimental room. This means increasing the operating range of diagnostic monitors including the Beam Position Monitors (BPM). Twenty BPM are installed in the warm sections of the linac to measure positions, ellipticities and phases. The digital processing of the BPM acquisition has been modified to operate at low intensity. This was done by improving the signal-to-noise ratio with an increase of the averaging resolution, an improvement of the channel equalisation system and with a deduction of parasitic signals induced by the surrounding equipment. The process was also modified to operate with chopper frequencies between 1 Hz and 1 kHz. A new BPM interface, with tables and graphical displays in order to control beam phases and energies in the linac, is now available. These new developments and measurement results in laboratory and with SPIRAL2 beams are presented, which show good results with a low intensity down to 1 µA.
Paper: WEPMO12
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-WEPMO12
About: Received: 29 Aug 2025 — Revised: 05 Sep 2025 — Accepted: 10 Sep 2025 — Issue date: 20 Jan 2026
WEPMO13
Single-shot detection of short electron bunch shapes at MHz repetition rates using diversity electro-optic scheme with advanced reconstruction algorithms at EuXFEL and FLASH
746
To surpass limitations in sub-picosecond electro-optic electron bunch length diagnostics[1], we present an innovative detection method utilizing diversity schemes[2]. This approach employs simultaneous multi-output measurements of the chirped optical probe modulated by the electron bunch's field. We introduce a novel inversion algorithm that automatically recognizes and compensates for imperfections in the probe laser spectrum and chirp, enabling high-fidelity retrieval of bunch shapes, particularly for broadband THz radiation over a long temporal window. Numerical simulations and initial experimental results demonstrate the system's potential for advanced, real-time bunch shape monitors at FLASH and EuXFEL, and can be extended to THz CTR or FEL based THz sources. [1] F. Sun, Z. Jiang, and X.-C. Zhang, Appl. Phys. Lett. 3, 2233 (1998) [2] E. Roussel et al., Light: Science & Applications 11, 14 (2022)
Paper: WEPMO13
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-WEPMO13
About: Received: 03 Sep 2025 — Revised: 08 Sep 2025 — Accepted: 09 Sep 2025 — Issue date: 20 Jan 2026
WEPMO15
Timing system at the Canadian Light Source
749
The Canadian Light Source (CLS) is a third generation 2.9 GeV synchrotron comprised of a 250 MeV LINAC, a full energy booster, and a storage ring with 13 insertion devices and 22 operational beamlines ranging from infrared light to hard X-rays. The Timing System supplies the triggers required to synchronize operation of all components responsible for injecting current into the storage ring. Signals from the Timing System can also be used to synchronize data acquisition on beamlines. The Trigger Generator Unit (TGU), which was designed by the CLS, is the centerpiece of the timing electronics. The TGU is driven by the 500 MHz master oscillator and is controlled using digital I/O. The trigger signals are distributed via a fiber optic system, which was also designed in house. The Timing System has been in operation since 2001 and has proven itself to be stable and robust. This paper provides a detailed overview of the system and its history and operational performance.
Paper: WEPMO15
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-WEPMO15
About: Received: 03 Sep 2025 — Revised: 04 Sep 2025 — Accepted: 10 Sep 2025 — Issue date: 20 Jan 2026
WEPMO16
A compact device for measuring and monitoring the energy of accelerated particle beams
752
A Beam Energy Monitor (BEM) was developed for the cyclotron of the HUN-REN ATOMKI, using TOF measurements on a short flight path. The sensor unit uses two capacitive probes at a distance of 20 cm, the entire geometry is about 40 cm long. The compact size allowed the unit to be installed in the main beamline, making it possible to measure and monitor the beam energy independently of the beamline actually used. The probe signals are acquired by a digital oscilloscope and the time difference between the pulses generated by a beam bunch on the probes is determined by digital signal processing algorithms. The unique design* of the sensor unit and the signal processing hardware and software combine to provide accurate beam energy measurement despite the short flight path. Accuracy in practical operation was investigated by neutron threshold reactons. They showed that the measurement accuracy is at least one order of magnitude better than the accuracy of the energy value calculated from the cyclotron settings. The accuracy of the signal processing shows that the beam energy can be scaled up to several hundred MeV while maintaining the measurement accuracy at the tenth of a percent level.
Paper: WEPMO16
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-WEPMO16
About: Received: 07 Aug 2025 — Revised: 07 Sep 2025 — Accepted: 08 Sep 2025 — Issue date: 20 Jan 2026
WEPMO19
Longitudinal profile measurements of particle beams with deconvolution in the APS-U Storage-ring
763
Accurate measurement of the longitudinal profile, or bunch length, of particle beams is essential for evaluating and optimizing beam quality in the Advanced Photon Source Upgrade (APS-U) Storage Ring. While Beam Position Monitor (BPM) signals are typically used for precise position measurements, they also contain information about the longitudinal bunch distribution, convolved with the BPM system’s transfer function. To extract the true bunch profile, CST Studio is used to simulate the BPM response to a short Gaussian pulse—approximating a Dirac delta function—thereby providing the BPM’s transfer function. The transfer functions of signal cables and attenuators are also measured and combined with the simulated BPM response to construct a complete system transfer function. This composite response serves as the deconvolution kernel for reconstructing the original time-domain bunch profile from the measured BPM signals. BPM signals from the APS-U’s tuned Bunch Lengthening System (BLS) are analyzed in both time and frequency domains. Deconvolution with the simulated transfer function yields accurate longitudinal profiles and enables precise extraction of bunch lengths.
Paper: WEPMO19
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-WEPMO19
About: Received: 02 Sep 2025 — Revised: 09 Sep 2025 — Accepted: 09 Sep 2025 — Issue date: 20 Jan 2026
WEPMO22
Button-type beam position monitors for Elettra 2.0: from design to real measurements
774
This paper describes the main stages of the journey from preliminary ideas on button shapes to actual measurements on prototypes of Beam Position Monitor (BPM) devices for Elettra 2.0. In the first stage, the electromagnetic phenomena involved in BPM sensors were studied taking into account different pick-up geometries, dielectric and conductive materials, and bunch lengths. Critical aspects such as beam coupling impedance, transfer impedance, impedance matching, trapped/propagating mode effects and heating were evaluated through numerical simulations. In the second stage, three families of vacuum-tight pick-up samples were fabricated in-house, and their actual performance was evaluated both on a microwave test bench and in real operating conditions on the Elettra storage ring. To carry out future measurements on alternative BPM designs, the third family was specifically conceived and built to allow quick and easy pick-up replacement using ultra-high vacuum shape memory alloy sealing technology. The third stage focused on comparing the signals produced by the Elettra BPMs with those foreseen for Elettra 2.0, and also allowed validation of the in-house developed BPM electronics.
Paper: WEPMO22
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-WEPMO22
About: Received: 03 Sep 2025 — Revised: 04 Sep 2025 — Accepted: 10 Sep 2025 — Issue date: 20 Jan 2026
WEPMO28
Optimisation of a fibre-based two-colour balanced optical cross-correlator
795
As part of the ongoing Full Energy Beam Exploitation (FEBE) upgrade to the Compact Linear Accelerator for Research and Applications (CLARA) at the Daresbury Laboratory, UK, few-femtosecond optical synchronisation between the new Ti:Sapphire terawatt FEBE laser and the Er:Yb optical master oscillator (OMO) is required for user experiments. To achieve this, a fibre-based two-colour balanced optical cross-correlator (BOXC) using waveguided periodically-poled lithium niobate (PPLN) crystals is being developed. A fibre-based BOXC could have greater sensitivity to timing jitter between two lasers than traditional free-space devices. In this manuscript, the design of the fibre-based two-colour BOXC is presented. The effect of pulse chirp on the sensitivity of the BOXC is investigated, and plans for optimising the design of the BOXC are discussed along with plans for integrating the fibre-based BOXC into the optical synchronisation network at Daresbury.
Paper: WEPMO28
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-WEPMO28
About: Received: 03 Sep 2025 — Revised: 05 Sep 2025 — Accepted: 10 Sep 2025 — Issue date: 20 Jan 2026
WEPMO31
Noninterceptive beam energy measurement of high-frequency free electron lasers
806
Free electron lasers (FEL), which can generate ultra-high brightness rediation are working horses for radiation science research over the world. For FEL, the higher the repetition frequency of the beam in the device, the higher the user's experimental efficiency, and more experimental stations can conduct experiments simultaneously. Therefore, there is a trend to increase the repetition frequency in its development process. Therefore, it is necessary to develop relevant technologies for high repetition frequency FEL. Beam energy is one of the most fundamental and critical parameters in FEL. This paper developed a fusion algorithm based on beam position monitor (BPM) in the dispersion structure of a FEL, which extracts the transverse position of the beam using both the arrival time and amplitude information of the beam, to achieve high-precision and noninterceptive measurement of beam energy. Provide powerful diagnostic, operational, and maintenance tools for high-frequency free electron laser devices.
Paper: WEPMO31
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-WEPMO31
About: Received: 02 Sep 2025 — Revised: 09 Sep 2025 — Accepted: 09 Sep 2025 — Issue date: 20 Jan 2026
WEPMO36
Concepts for beam diagnostics based on planar pickups on a printed circuit board
821
For the upgrade of the electro-optical bunch arrival-time monitors (EO-BAMs) employed at several free-electron laser (FEL) facilities, a novel pickup structure has been proposed. Its feasibility was successfully tested at the ELBE accelerator. The design comprises planar pickups on a printed circuit board (PCB) with an integrated combination network. It delivers a significantly stronger signal compared to established pickups. Applying the upgrade to existing machines enables two key capabilities: Reliable operation at 1 pC charge levels for FELs and ultrafast electron diffraction facilities, and enhanced arrival-time resolution for standard operational modes. Furthermore, the PCB implementation enables unprecedented flexibility in planar pickup design, facilitating multi-functional diagnostic capabilities. This work presents a compact implementation strategy for integrating high- and low-resolution channels for EO-BAMs on a single substrate through a dual-functionality layout, and conceptual advancements in beam diagnostics using a PCB architecture for measuring other beam properties.
Paper: WEPMO36
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-WEPMO36
About: Received: 03 Sep 2025 — Revised: 09 Sep 2025 — Accepted: 11 Sep 2025 — Issue date: 20 Jan 2026
WEPMO37
Preliminary radiation hardness characterization of ultra-broadband direct THz detectors based on Schottky diodes and GaAs TeraFETs
825
Many currently operating and future FELs can generate radiation at megahertz repetition rates, requiring an ultra-broadband, compact, robust & fast (response time at least on a single-digit nanosecond scale) diagnostic tool. We develop ultrafast-operating terahertz detectors based on Schottky diodes and GaAs field-effect transistors (TeraFETs) that operate at room temperature. Here, we present the preliminary radiation hardness characterization of these detectors. Promising results demonstrate the ability of these detectors to be commissioned at accelerator facilities for longitudinal beam diagnostics.
Paper: WEPMO37
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-WEPMO37
About: Received: 03 Sep 2025 — Revised: 06 Sep 2025 — Accepted: 09 Sep 2025 — Issue date: 20 Jan 2026
WEPMO40
Optimization and upgrade of the BPM electronics system for CSNS-II RCS
829
As the China Spallation Neutron Source (CSNS) Phase II project increases the Rapid Cycling Synchrotron (RCS) power to 500 kW, the signal intensity of Beam Position Monitors (BPMs) is expected to rise tenfold, necessitating a comprehensive upgrade of the electronics system to meet high-power operational requirements. Drawing on the experience of the J-PARC Main Ring (MR) 1.3 MW power upgrade, CSNS optimized the analog front-end using a MicroTCA-based RTM board. The initial four-stage passive resistive divider was upgraded to a switchable attenuator combined with proportional voltage division, alongside impedance matching techniques, ensuring stable signal attenuation under high input voltages, minimal reflections, and compatibility with the Analog-to-Digital Converter (ADC) dynamic range. The digital processing is implemented on a self-developed MicroTCA.4-based AMC board, utilizing the Xilinx Zynq-7045 SoC with 8 channels of 16-bit ADC (125 MSPS). The system has successfully transplanted algorithms, supports real-time beam position calculations, and publishes position signals via EPICS. Tests demonstrate low noise, high linearity, and performance.
Paper: WEPMO40
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-WEPMO40
About: Received: 03 Sep 2025 — Revised: 10 Sep 2025 — Accepted: 10 Sep 2025 — Issue date: 20 Jan 2026
THBC01
High-performance bunch arrival time monitors with fs precision at DESY
832
Pump-probe experiments at Free-Electron Laser facilities depend heavily on the relative timing precision of the pump and the probe, which determines the resolution of the observed ultrafast phenomena. The DESY's Bunch Arrival Time Monitors (BAM) are state-of-the-art sensors based on an electro-optical detection principle, that delivers information on the bunch timing with unprecedented femtosecond-level precision. Timing synchronization at machine level is achieved through a complex system of arrival time sensors, stabilized optical distribution, and feedback controls. Major advances in the performance, construction, and operation of the BAMs are discussed in detail. Integration of the sensor into the synchronization system, and important global optimization and interplay are mentioned as well. These improvements enabled a synchronization of the electron beam with a world-leading precision of less than 3fs at European XFEL.
Paper: THBC01
DOI: reference for this paper: 10.18429/JACoW-IBIC2025-THBC01
About: Received: 02 Sep 2025 — Revised: 06 Sep 2025 — Accepted: 08 Sep 2025 — Issue date: 20 Jan 2026