MOP
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Monday Poster Session
11 Aug 2025, 16:00 -
18:00
MOP001
Accelerator drift compensation via a modified MG-GPO algorithm
34
Performance drift over long periods of operation due to changes in machines settings or the environment has been a longstanding problem for particle accelerators. Algorithms which are capable of tuning machine settings while keeping the performance within a desired threshold can be used to compensate for such drifts. We have developed a modified version of the Multi-Generation Gaussian Process Optimizer (MG-GPO) which is capable of tuning accelerator settings during user operation. The modified algorithm uses Gaussian Process regression to predict the performance of potential trial settings and removes ones with a high probability of giving too poor of a performance before selection for evaluation on the machine. The modified MG-GPO has been tested on analytic functions and applied to the SPEAR3 kicker-bump matching problem as a proof of concept. It is expected that the modified MG-GPO will be applied to maintain optimal trajectory of the beam injected into the SPEAR3 storage ring.
Paper: MOP001
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP001
About: Received: 08 Aug 2025 — Revised: 13 Aug 2025 — Accepted: 14 Aug 2025 — Issue date: 28 Jan 2026
MOP002
Advancing accelerator virtual beam diagnostics through Latent Evolution Modeling: An integrated solution to forward, inverse, tuning, and UQ problems
38
Virtual beam diagnostics relies on computationally intensive beam dynamics simulations where high-dimensional charged particle beams evolve through the accelerator. We propose Latent Evolution Model (LEM), a hybrid machine learning framework with an autoencoder that projects high-dimensional phase spaces into lower-dimensional representations, coupled with transformers to learn temporal dynamics in the latent space. This approach provides a common foundational framework addressing multiple interconnected challenges in beam diagnostics. For forward modeling, a Conditional Variational Autoencoder (CVAE) encodes 15 unique projections of the 6D phase space into a latent representation, while a transformer predicts downstream latent states from upstream inputs. For inverse problems, we address two distinct challenges: (a) predicting upstream phase spaces from downstream observations by utilizing the pretrained CVAE with transformers trained on reversed temporal sequences, and (b) estimating RF settings from the latent space of the trained LEM using a dedicated dense neural network that maps latent representations to RF parameters. For tuning problems, we leverage the trained LEM and RF estimator within a Bayesian optimization framework to determine optimal RF settings that minimize beam loss. This paper summarizes our recent efforts and demonstrates how this unified approach effectively addresses these traditionally separate challenges.
Paper: MOP002
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP002
About: Received: 08 Aug 2025 — Revised: 13 Aug 2025 — Accepted: 14 Aug 2025 — Issue date: 28 Jan 2026
MOP003
AI-ready control infrastructure for cyclotron systems using GPU-accelerated Python GUIs and LabVIEW over ZeroMQ
42
We present a modular, AI-ready control and monitoring infrastructure developed for the 76-inch isochronous cyclotron at the Crocker Nuclear Laboratory, University of California, Davis. The system combines a GPU-accelerated Python GUI engine on a high-performance Linux workstation with a LabVIEW-based supervisory platform for real-time control and data acquisition. Communication between platforms is handled via ZeroMQ, enabling low-latency, asynchronous data exchange. Benchmark results show end-to-end response times below 10 ms with minimal jitter, supporting real-time visualization and interactive feedback. Designed to separate deterministic control from high-level logic and user interaction, this architecture offers robust performance, scalability, and extensibility. It lays the groundwork for future integration of AI-based optimization, autonomous control, and predictive diagnostics in cyclotron operations.
Paper: MOP003
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP003
About: Received: 08 Aug 2025 — Revised: 17 Aug 2025 — Accepted: 17 Aug 2025 — Issue date: 28 Jan 2026
MOP004
Analog signal multiplexing system for the IOTA Proton Injector
45
The Fermilab Accelerator Science and Technology (FAST) Facility at FNAL is a dedicated research and development center focused on advancing particle accelerator technologies for future applications worldwide. Currently, a key objective of FAST Operations is to commission the 2.5 MeV IOTA Proton Injector (IPI) and enable proton injection into the IOTA storage ring. The low and medium-energy sections of the IPI include four frame-style dipole trims and two multi-function correctors with independently controlled coils, requiring readout of 32 analog channels for current and voltage monitoring in total. To reduce cost and optimize rack space within the PLC-based control system, a 32-to-4 analog signal multiplexing system was designed and implemented. This system enables real-time readback of excitation parameters from all magnetic correctors. This paper presents the design, construction, implementation, and performance of the multiplexing system.
Paper: MOP004
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP004
About: Received: 05 Aug 2025 — Revised: 12 Aug 2025 — Accepted: 13 Aug 2025 — Issue date: 28 Jan 2026
MOP005
A new Python middle layer framework: Particle Accelerator MIddle LAyer (PAMILA)
48
MATLAB Middle Layer (MML) for accelerator control has been used by many facilities worldwide over the years. With the rise of Python's popularity, particularly for leveraging its advanced artificial intelligence and machine learning libraries, an international collaboration is underway to develop a similar software framework in Python. As part of this effort, we propose a new Python middle layer package, which is built on top of the pint unit-conversion package, and capable of handling any type of device-dependent unit conversion (including multiple-input multiple-output) for magnets and other equipment. This package is also compatible with a suite of modern experimental orchestration and data management tools widely used by beamlines at many light sources (i.e., bluesky, ophyd, and tiled),and provides a more modular approach for implementing high-level applications, facilitating re-use, while exposing comprehensive, yet manageable, options to end users.
Paper: MOP005
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP005
About: Received: 08 Aug 2025 — Revised: 12 Aug 2025 — Accepted: 12 Aug 2025 — Issue date: 28 Jan 2026
MOP006
A self-supervised transformer for RF cavity signal denoising
52
A frequent occurrence within industrial particle accelerator systems is electromagnetic noise accumulating within RF Cavity Sensor readings, attributed to their electromagnetically dirtier operating environments and production, with less of an emphasis on their performance optimization. This phenomenon prevents signals from accurately relaying information to beam operators and specialists. Additionally, noisy signals inhibit the ability for feedback loops to meet their regulation requirements, making machine control much more difficult. Previous work has shown machine learning-based techniques as promising solutions for denoising that maintains signal quality and features. In this paper, we design, implement, and benchmark a self-supervised transformer-based machine learning algorithm that denoises In-Phase and Quadrature (I/Q) RF Cavity Signals without a need for referencing a clean ground-truth.
Paper: MOP006
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP006
About: Received: 08 Aug 2025 — Revised: 10 Aug 2025 — Accepted: 12 Aug 2025 — Issue date: 28 Jan 2026
MOP007
Anomaly detection of slow-moving variables at LANSCE for improved beam quality
55
Modern accelerator facilities operate with a large number of variables, many of which can influence beam quality. While most of these variables are constrained within predefined boundary conditions, slow fluctuations over extended periods—from tens of minutes to a full day—can still significantly degrade beam performance. Due to their gradual nature and the difficulty in distinguishing meaningful trends from background noise, such variables often go unnoticed and remain unoptimized by operators for days. This study investigates the use of machine learning algorithms to identify and analyze these slow-moving variables. By applying advanced time-series analysis and feature importance ranking, the proposed approach reveals hidden correlations between slow variable drifts and a key beam quality metric: the ring loss at the Los Alamos Neutron Science Center (LANSCE). The results demonstrate the potential of machine learning to detect subtle anomalies and offer actionable insights to mitigate persistent beam quality issues that can disrupt operations for weeks at a time.
Paper: MOP007
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP007
About: Received: 07 Aug 2025 — Revised: 11 Aug 2025 — Accepted: 13 Aug 2025 — Issue date: 28 Jan 2026
MOP008
Application of Bayesian optimization to BtA injection at BNL
58
Drifting optimal settings and changing working conditions force accelerator operators to keep re-tuning control systems. At BNL, the RHIC injector complex accelerates many different ion species by varying a multitude of control knobs. In this report, we investigate the use of Bayesian optimization (BO) of the Booster-to-AGS (BtA) transfer line to maximize the beam brightness in the AGS. The most suitable magnets were chosen by an investigation of the betatron phase advance to facilitate an efficient BO process, using up to 4 steering magnets and up to 3 quadrupoles. To quantify the beam intensity, we used an integrated current transformer, while the beam emittance was estimated via an Ionization Profile Monitor (IPM). It was demonstrated that the chosen magnets effectively recovered a high intensity beam from a poorly tuned configuration, using an Xopt implementation of BO, without increasing the beam profile. A new electron-collecting IPM is being configured with better systematics and lower noise compared to the current ion-collecting IPM, which can further improve this process.
Paper: MOP008
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP008
About: Received: 08 Aug 2025 — Revised: 09 Aug 2025 — Accepted: 15 Aug 2025 — Issue date: 28 Jan 2026
MOP009
A reactive ferroelectric tuner for microphonics compensation
61
Jefferson Lab (JLab) is actively pursuing an extensive research program focused on developing advanced Nb₃Sn superconducting technology for particle accel-eration. Due to the brittle nature of Nb₃Sn coatings, a Ferroelectric Tuner (FRT) currently represents the most viable approach for microphonics compensation in these next-generation cavities. We suggest a novel, fast-responding FRT integrated directly into the main coupler, eliminating the need for an additional RF port. Leveraging a unique RF design based on a magic-T configuration, this advanced FRT will enable micro-phonics compensation in the ±30 Hz range without undesirable changes to the external quality factor.
Paper: MOP009
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP009
About: Received: 01 Aug 2025 — Revised: 12 Aug 2025 — Accepted: 12 Aug 2025 — Issue date: 28 Jan 2026
MOP010
AtomicAndPhysicalConstants.jl – A fast Julia package to access particle properties and fundamental constants
65
To support constants lookup for the SciBmad project, we introduced AtomicAndPhysicalConstants.jl, a Julia package that provides physical constants, subatomic particle properties, and atomic isotope data. It aggregates datasets from NIST (CODATA) and the Particle Data Group, offering a unified interface. The package supports configurable unit systems and data types, and integrates with the Julia package Unitful.jl. The package emphasizes speed and ease of use, making it well-suited for high-performance simulations and physics-driven modeling.
Paper: MOP010
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP010
About: Received: 07 Aug 2025 — Revised: 14 Aug 2025 — Accepted: 14 Aug 2025 — Issue date: 28 Jan 2026
MOP011
Automated RF phase adjustment for beam stabilization in the Fermilab Linac
68
The Fermilab Linac delivers 400 MeV H- beam. Variations in environmental factors and Ion Source output result in day-to-day longitudinal phase drift leading to increased beam loss. Traditionally, phase drift is corrected by manual RF cavity phase adjustments, a process that is labor-intensive and suboptimal. This work explores machine learning-based automation of drift correction using data-driven modeling of the Linac behavior. After extensive experimentation with single-layer, multi-layer, and convolutional neural networks (CNN+NN), we now adopt a prototype-based classification approach to identify optimal correction strategies. The model leverages a reduced 34-dimensional feature set comprising 7 RF cavity settings and 27 Beam Position Monitor (BPM) phase readings. To model the beam longitudinal response, we construct a 7×27 response matrix by varying the 7 cavity phases. Due to the limited set real-world data, synthetic data generation from the response matrix is also being explored to enhance model training. This enables the simulation of diverse drift scenarios and improves the generalizability of learned corrections. Finally, in addition to the prototypical loss framework, we incorporate a surrogate energy-consistent loss that penalizes inconsistencies between predicted phase corrections and changes in beam energy—estimated from the 27 BPM readings—alongside a temporal smoothness constraint that discourages abrupt prediction shifts across sequential readings.
Paper: MOP011
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP011
About: Received: 08 Aug 2025 — Revised: 13 Aug 2025 — Accepted: 14 Aug 2025 — Issue date: 28 Jan 2026
MOP012
Automation of sample alignment for neutron beamlines
72
Neutron scattering experiments are crucial for the exploration of molecular structure in compounds. The HB-2A neutron powder diffractometer at the High Flux Isotope Reactor at Oak Ridge National Laboratory conducts magnetic studies of samples by illuminating them with different energy neutron beams and recording the scattered neutrons. Proper and consistent alignment of the sample is necessary to ensure that high quality data is collected throughout an experiment. This process is currently performed manually by beamline scientists. RadiaSoft, in collaboration with the beamline scientists and engineers at ORNL, has developed a reinforcement learning-based agent capable of aligning and isolating samples. We use a Q learning structure to train the agent. The agent identifies the method to move the sample to the center of the beam and the proper amount to close the neutron camera slits. We then move the sample and close the slits using a custom Python-based EPICS IOC interfaced with the sample and slit motors. In this paper, we provide an overview of our reinforcement learning tools and show our results aligning samples like those at ORNL.
Paper: MOP012
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP012
About: Received: 10 Aug 2025 — Revised: 14 Aug 2025 — Accepted: 14 Aug 2025 — Issue date: 28 Jan 2026
MOP013
Automation of sample identification for neutron beamlines
74
Neutron scattering experiments are a critical tool for the investigation of molecular structure in compounds. The HB-2A neutron powder diffractometer at the High Flux Isotope Reactor at ORNL conducts magnetic studies of samples by illuminating them with different energy neutron beams and recording the scattered neutrons. Proper identification and alignment of samples during an experiment is key to ensuring high quality data is collected. At present, this process is performed manually by beamline scientists. RadiaSoft, in collaboration with the beamline scientists and engineers at ORNL, has developed a machine learning-based software automating sample identification. We utilize a fully connected convolutional neural network configured in a U-Net architecture to identify the sample and its center of mass. We then move the sample using a custom Python-based EPICS IOC interfaced with the motors. In this poster, we provide an overview of our machine learning tools and show our results identifying samples at ORNL.
Paper: MOP013
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP013
About: Received: 08 Aug 2025 — Revised: 14 Aug 2025 — Accepted: 14 Aug 2025 — Issue date: 28 Jan 2026
Bayesian calibration of the AWA photocathode gun using YAG screen diagnostics and OPAL simulations
We present a data-driven characterisation of the photocathode gun at the Argonne Wakefield Accelerator (AWA) using Bayesian inference, combined with OPAL beam dynamics simulations. Our methodology employs readily available YAG screen diagnostics to perform calibration across a range of experimental conditions, including varying cathode voltages, laser profiles, and beam currents. By integrating these diagnostics with forward beam dynamics simulations from OPAL, we estimate key gun parameters, such as the gun voltage and phase from beam current and solenoid currents. Ongoing work will further refine the calibration process and explore the integration of other diagnostics to enhance the inference process. This allows for more efficient and flexible calibration of complex accelerator systems, particularly with limited readily available measurements
MOP015
Beam scattering through foil
77
This paper describes the foil structure used at the beam extraction point in the NASA Space Radiation Laboratory (NSRL) beamline. The stripping foil removes electrons from incoming ions, rendering them partially or fully stripped. Foils of various materials and thicknesses are employed, enabling ion species at different energies to pass through. As charged particles traverse a foil, the outgoing particles exhibit a Gaussian-like angular distribution. This distribution is subsequently transformed into a uniform profile by a set of octupole magnets, essential for various beam experiments at the NSRL target. We utilize the Bmad and SRIM computer codes to calculate the energy loss through the foils for different ion species, energies, and charge states. After preparing ion beam species in the Booster, we determine the energy loss by measuring the horizontal beam profile at the multi-wire MW063 location in the NSRL beamline. Finally, we present a summary of energy loss calculations obtained through Bmad, SRIM, and experimental data.
Paper: MOP015
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP015
About: Received: 06 Aug 2025 — Revised: 12 Aug 2025 — Accepted: 12 Aug 2025 — Issue date: 28 Jan 2026
MOP016
Benchmarking the use of BPM quadrupole moments to measure emittance
81
For the PIP-II program, transverse emittance in the Fermilab Booster must remain well controlled at higher bunch intensities. 4-plate beam position monitors (BPMs) have a small but measurable quadrupole moment, making it possible to infer transverse emittance. By compositing many BPMs together, it becomes possible to improve the quality of the quadrupole signal. The Fermilab Booster BPM system has been used to measure these quadrupole moments in the past year and derive emittances from them. Recent benchmarks show that the derived BPM emittances show similar emittance evolution and value to IPM and Multiwire data. This approach can both supplement and complement existing non-intercepting emittance monitors in accelerators.
Paper: MOP016
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP016
About: Received: 07 Aug 2025 — Revised: 10 Aug 2025 — Accepted: 14 Aug 2025 — Issue date: 28 Jan 2026
Tool chain for simulations of bi-filar coil winding for fast quench protection
The advancement of high-field magnets utilizing high-temperature superconductors (HTS) brings about complex challenges, especially in quench detection and protection. Traditional methods often fall short due to the inherently slow quench propagation in HTS materials. One promising approach to overcome this involves using a bifilar winding configuration, where two conductors are placed side by side. Under normal operation, they function in series, but during a quench event, they switch to an anti-parallel mode. This shift reduces the differential inductance of the coil to near zero, enabling rapid current oscillations through a capacitor discharge. The resulting high-frequency current flow leads to swift, uniform heating, triggering a full-coil quench within microseconds. Moreover, the strong mutual coupling between the two windings significantly reduces electrical noise in voltage measurements. In this work, we explore the viability of this concept by designing, constructing, and testing a REBCO bifilar racetrack coil in liquid nitrogen. We also present a validated simulation model that closely mirrors the coil's dynamic behavior under these conditions, aligning well with experimental observations.
MOP018
Modernizing wire scan diagnostics for reproducible, real-time beam measurements through a modular Python middle layer integrated with EPICS
85
As part of a broader effort to modernize beam diagnostics at SLAC, we are developing a new middle-layer application to support wire scan measurements using Python. This tool is designed to replace aging MATLAB GUIs with a streamlined framework that interfaces directly with EPICS and Beam Synchronous Acquisition systems. The middle layer manages the complete wire scan workflow while emphasizing modularity, reproducibility, and integration with existing controls infrastructure. This talk will cover the system architecture, practical implementation details, and lessons learned in deploying a diagnostic tool suited to the high-throughput, real-time needs of accelerator operations.
Paper: MOP018
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP018
About: Received: 08 Aug 2025 — Revised: 12 Aug 2025 — Accepted: 12 Aug 2025 — Issue date: 28 Jan 2026
MOP019
Bunch duration measurements in the APS-U booster
88
We present the results of time-based, bunch length measurements in the Advanced Photon Source Upgrade booster synchrotron using the bunch duration monitor (BDM) optical diagnostic. The BDM diagnostic is based on the detection of visible-wavelength synchrotron radiation. The detector is a metal-semiconductor-metal device followed by 42 dB of wide-band amplifier gain. Bunch duration is determined by de-convolving the raw output signal with the circuit’s impulse response function. The BDM allows measurement of bunch duration over virtually the entire booster ramp. De-focusing in the optical path was necessary to overcome thermal steering from the in-tunnel mirror. Also, the effects of detector saturation must be considered to ensure a linear response. Presently, the booster increases bunch energy from 425 MeV to 6 GeV. Booster charge varies from 5 nC to 13 nC depending on storage ring operating modes. BDM data reveal that the bunch undergoes large longitudinal oscillations shortly after injection into the booster. The longitudinal oscillations are compared with elegant simulations. These oscillations are a source of injection loss especially at higher charge.
Paper: MOP019
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP019
About: Received: 07 Aug 2025 — Revised: 12 Aug 2025 — Accepted: 13 Aug 2025 — Issue date: 28 Jan 2026
MOP020
Towards real-time calibration of CBPMs using synchronous RF injection
92
Cavity beam position monitors (CBPMs) are very high-precision devices that, in recent years, have progressed from experimental equipment to standard linac diagnostics in many prominent facilities, most notably free electron lasers. However, the high sensitivity of these devices comes at the cost of a limited measurement range, even with high dynamic range electronics. Furthermore, CBPMs need to be calibrated in situ, ideally by introducing a known beam offset, which is often impractical in large installations. This paper reports on a method to match CBPM beam signals by injecting synchronized and tightly controlled bursts of radio frequency (RF) oscillations into the sensor cavity and reading back their superposition. The method allows compensation for static beam offsets (with beam) and calibrates CBPMs electronically (no beam required), thus removing some of the operational hurdles. We discuss the first demonstration of this method at the Accelerator Test Facility 2 (ATF2).
Paper: MOP020
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP020
About: Received: 08 Aug 2025 — Revised: 14 Aug 2025 — Accepted: 15 Aug 2025 — Issue date: 28 Jan 2026
MOP021
Compact 3D electro-optic sampling beam position monitor
96
RadiaBeam and University of Colorado Boulder have developed a 3D beam position monitor based on the well-established electro-optic sampling (EOS) technique, enabling non-interceptive, ultrafast position monitoring of high-intensity femtosecond beams. Based on the initial prototype of the 2D EOS-BPM, using 1 pair of crystals, installed at SLAC FACET-II, this 3D design has undergone several iterations. A fully functional prototype was manufactured and bench tested using Off-Axis Parabolic (OAP) mirrors to focus the laser on 2 sets of 2 crystals. However, due to the difficulty of working with OAPs and the offset of the crystal pairs, a new EOS-BPM was developed using an axicon lens to shape the laser into an annulus at the crystal plane. This dramatically simplifies the setup, reduces its footprint, and provides full 3D information from a single laser beam. Once installed, the EOS-BPM can yield the full 3D centroid positioning of two bunches in a wakefield accelerator, or the tilt of a beam used to power a light source. Under ideal conditions, simulation-based estimates show temporal and transverse resolution for the beam centroids of a two-bunch wakefield accelerator beam of order 50 fs and 1 μm, respectively.
Paper: MOP021
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP021
About: Received: 09 Aug 2025 — Revised: 12 Aug 2025 — Accepted: 14 Aug 2025 — Issue date: 28 Jan 2026
Nested extremum seeking for virtual diagnostics and control
Machine learning methods have been increasingly used to model complex physical processes that are difficult to address with traditional approaches, especially when these processes exhibit temporal dynamics or require real-time implementation. The linear accelerator (LINAC) at the LANSCE facility is one such system. While a high-resolution simulation tool, HPSim, exists, the complexity and high computational costs of the simulation, combined with the spatiotemporal variability of the LINAC and limited diagnostic measurements, creates challenges for real-time operation. These challenges can be mitigated by developing fast surrogate machine learning models to provide virtual diagnostics and enable control. However, the highly expressive nature of machine learning models often results in opaque representations, complicating their use in control applications. Control design and tuning are significantly simplified when the system dynamics are captured by a more interpretable, parsimonious model. This study seeks to harness the power of machine learning while applying traditional system identification techniques to develop models that are both effective for control and computationally efficient.
MOP025
Design, characterization, and validation of a pulsed RF burst source for in-situ cavity beam position monitor calibration
98
Beam Position Monitors are critical instruments in accelerator facilities, providing precise beam orbit measurements with tens of nanometers resolutions, essential for the operation of current linac-based FELs and future linear colliders. In this report, we introduce the development and successful testing of a pulsed RF burst source specifically designed for BPM calibration. The source was characterized and installed at the ATF2 facility in KEK, Japan. The system injects tailored RF pulses into the BPM cavity via one of the two output ports. With the capability to adjust frequency and pulse width, to emulate beam pulses, the system demonstrated nearly complete cancellation of beam-generated signals when the injected RF pulse overlapped with the beam pulse. This source has the potential for in-situ BPM calibration, mitigation of static signal contributions caused by cavity misalignments and capacity for wakefield compensation. Dedicated hardware development for further refinement of the source is underway at Royal Holloway, University of London, using two TI LMX2820 high-frequency synthesizers triggered by a shared external source to achieve precise phase synchronization between distinct frequencies at defined delays. Preliminary measurements indicate a phase jitter of about 1.2 degrees, currently limited by the trigger signal’s slow rising edge (tens of ns), while system requirements demand sub-nanosecond (hundreds of ps) precision for robust, high-frequency phase locking.
Paper: MOP025
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP025
About: Received: 07 Aug 2025 — Revised: 11 Aug 2025 — Accepted: 11 Aug 2025 — Issue date: 28 Jan 2026
MOP026
Design of phase diversity Electro-Optic Sampling of THz coherent transition radiation
102
We report progress on the design of a Phase Diversity Electro-Optic Sampling (DEOS)-based longitudinal profile measurement system. The current design uses THz coherent transition radiation (CTR) to convey the bunch’s longitudinal information. A 1550nm fiber laser available at the Argonne Wakefield Accelerator facility will be used as the probe for electro-optic sampling. Specifically, we discuss pulse synchronization and probe beam transport, the design and optimization of the probe beam stretcher, and the design of the probe beam detection system.
Paper: MOP026
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP026
About: Received: 08 Aug 2025 — Revised: 13 Aug 2025 — Accepted: 14 Aug 2025 — Issue date: 28 Jan 2026
Integrating community codes for accelerator design and optimization
Advances in fidelity and performance of accelerator modeling tools, in tandem with novel machine learning capabilities, has prompted community initiatives aiming to realize “virtual test stands” that can serve as true analogues to physical machines. Such efforts require integrated, end-to-end modeling capabilities with support for parametric optimization and benchmarking. We present the ongoing development of an integrated Sirepo application to support the holistic modeling of accelerators. Our approach leverages existing modeling workflows, such as the Light Source Unified Modeling Environment (LUME), as well as community I/O frameworks, such as openPMD, to provide a toolbox for constructing and modeling beamlines. Users can build and test simulations using different community modeling tools, as well as connect individual tools to produce end-to-end simulations. Additional workflows have been developed to support machine learning tools that facilitate optimization and the development of surrogate models. We discuss some specific beamline modeling demonstrations as well as ongoing efforts to support code-agnostic design and development.
MOP028
Facility-scale differentiable virtual accelerator at Fermilab
106
As the design complexity of modern accelerators grows, there is more interest in using advanced simulations and algorithms that have fast execution time or yield additional insights. One notable example are the gradients of physical observables with respect to design parameters, which are broadly useful in optimization and uncertainty analysis. The IOTA/FAST facility has been working on implementing and experimentally validating an end-to-end virtual accelerator test stand that is both fast and gradient-aware, allowing for rapid prototyping of new software and experiments with minimal beam time costs. We describe the selection and benchmarking of both physics and ML codes for linac and ring simulation, including obtaining parameter gradients with autodiff. We will also show the development of generic interfaces between surrogate and physics-based sections, and how the control interface is exposed as either a deterministic discrete event simulator or a fully asynchronous EPICS/ACNET soft IOC. We will also discuss challenges in model calibration and uncertainty quantification, as well as future plans to extend modelling to other Fermilab accelerators like PIP-II and Booster.
Paper: MOP028
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP028
About: Received: 10 Aug 2025 — Revised: 11 Aug 2025 — Accepted: 19 Aug 2025 — Issue date: 28 Jan 2026
MOP029
Development and applications of differentiable coherent optical transition radiation simulations
110
Optical transition radiation (OTR) beam profile monitors are widely used to measure the transverse profiles of low-charge electron bunches at advanced linear accelerator facilities such as LCLS-II and FACET-II. However, in scenarios involving strong longitudinal compression or microbunching-induced current spikes, the incoherent OTR signal—proportional to the transverse beam density—is often dominated by coherent OTR (COTR). The resulting COTR patterns exhibit complex dependencies on the full spatiotemporal structure of the beam, rendering conventional profile interpretation ineffective. In this work, we present a novel, backwards-differentiable simulation framework for COTR emission, enabling gradient-based inference of beam characteristics directly from COTR images. We further integrate this framework with the generative phase space reconstruction (GPSR) method to recover high-fidelity 4D transverse phase space distributions of strongly compressed beams. Simulation results demonstrate the ability of this approach to accurately reconstruct detailed beam structure from COTR-based diagnostics, offering a new path toward high-resolution characterization of ultrashort electron bunches.
Paper: MOP029
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP029
About: Received: 08 Aug 2025 — Revised: 13 Aug 2025 — Accepted: 14 Aug 2025 — Issue date: 28 Jan 2026
MOP030
Development of an upgraded fast orbit feedback system for NSLS-IIU
113
As light source facilities evolve, upgrading fast orbit feedback systems is essential for improving beam stability. NSLS-II is planning an upgrade to NSLS-IIU, which introduces stricter stability requirements for advanced experiments. To address this, we developed a next-generation fast orbit feedback prototype system to enhance noise suppression and extend control bandwidth beyond 1 kHz. A system-wide evaluation was conducted, covering beam position monitors, cell controllers, power supply controllers, power supplies, and vacuum chamber effects. Latency and bandwidth bottlenecks were identified in the cell and power supply controllers. A new cell controller was designed to increase the sampling rate from 10 kHz to 31.5 kHz and reduce system latency to under 70 µs. The transfer function and gain measurements of a single-input-single-output system show a 10-dB improvement in noise suppression and an extension of bandwidth into the kHz range. We present the development and performance results of the upgraded system, offering a path toward higher beam stability at NSLS-IIU.
Paper: MOP030
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP030
About: Received: 21 Jul 2025 — Revised: 09 Aug 2025 — Accepted: 10 Aug 2025 — Issue date: 28 Jan 2026
Development of diamond-based halo monitor diagnostics for an electron accelerator
High-resolution diagnostic instruments for measuring particle beam profile and charge are essential for characterizing the improved performance of charged particle accelerators. Beam diagnostics based on synthetic single crystal diamond (SCD) exhibit superior radiation-hardness, chemical stability, fast saturated drift speed, and unparalleled thermal conductivity. At Los Alamos National Laboratory (LANL), the SCD sensor and the high-speed signal acquisition system have been developed for measuring intensity of individual bunches. At the Argonne Wakefield Accelerator, a 63 MeV electron beam with diameter of 5 mm and charge below 10 pC used to measure the beam halo at a radial distance of 12 mm from the beam center. This presentation will report on the detailed SCD design and electronics, halo monitoring at various charges, bunches, and distances, and plans for future testing at LANL.
MOP032
Digital camera performance in a high-radiation accelerator test beam facility
117
Digital cameras are critical diagnostics at test beam facilities. At FACET-II, there are over 100 digital cameras in operation. The 10 GeV electron beams cause high levels of radiation, which makes profile monitors susceptible to two types of failures: single-event upsets (SEU) and permanent death. The Camera Watchdog software was deployed to monitor and automatically power cycle cameras in the case of an SEU. The Camera Watchdog also updates the total number of reboots executed for each camera. Additionally, digital radiation monitors (RADFETs) have been installed at the locations of 10 cameras. We report on the findings from the study and discuss how they can be used to mitigate radiation damage to digital cameras.
Paper: MOP032
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP032
About: Received: 08 Aug 2025 — Revised: 13 Aug 2025 — Accepted: 14 Aug 2025 — Issue date: 28 Jan 2026
Early prediction of system failures at Los Alamos Nuclear Science Center (LANSCE)
Accelerators are complex systems composed of tens of thousands of individual components requiring continuous maintenance. Aging facilities such as LANSCE face an increased rate of equipment failures, resulting in costly unscheduled shutdowns for maintenance. Early identification and localization of problems along the accelerator can mitigate future failures during scheduled maintenance periods rather than emergency shutdowns. This approach will significantly enhance the facility's reliability and increase beam availability for users. We have developed a mathematical formalism to analyze all available data for a LANSCE subsystem and generate signals indicating abnormal operation. The system accounts for hidden internal correlations between various parameters, which the existing warning system does not. This predicted deviation from the norm is supported by historical records in log files. We report progress on developing an anomaly detection system for LANSCE by expanding predictions to all subsystems, increase LANSCE's data archiving capability by an order of magnitude, and developing algorithms to provide operators with signals indicating developing abnormalities and pinpointing problematic beamline elements.
MOP034
Efficient 6-dimensional phase space measurements and applications to autonomous monitoring at LCLS-II
120
Increasing the performance and capabilities of free electron lasers, such as LCLS-II, hinges on our ability to precisely control and measure the 6-dimensional phase space distribution of the beam. However, conventional tomographic techniques necessitate a substantial number of measurements and computational resources to characterize a single beam distribution, using many hours of valuable beam time. Novel diagnostic techniques are needed to significantly reduce the number of measurements required to reconstruct detailed, 6-dimensional beam features to enable feedback for precision beam shaping for accelerators and characterize unknown physical phenomena. In this work, we present a novel approach to analyzing experimental measurements using differentiable beam dynamics simulations and generative representations of 6-dimensional phase space distributions. We discuss developments in combining this work with advanced accelerator control algorithms and parasitic beam measurements to autonomously monitor the 6-dimensional phase space distribution of the beam at LCLS-II during accelerator operations.
Paper: MOP034
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP034
About: Received: 08 Aug 2025 — Revised: 11 Aug 2025 — Accepted: 12 Aug 2025 — Issue date: 28 Jan 2026
MOP035
Experimental longitudinal emittance manipulation using laser-based photoionization in the Fermilab Linac
124
A series of simulations and beam studies were conducted at Fermilab’s linear accelerator to evaluate the effectiveness of longitudinal emittance control via laser-induced photoionization. While similar laser techniques have been employed at Fermilab to enhance injection and extraction efficiency into the Booster, the work presented here focuses on extending these methods to bunch-by-bunch manipulation. This approach utilizes fine-scale correction of the H- bunches’ longitudinal spatial distribution. In theory, loosely confined particles in longitudinal phase space contribute to emittance growth during acceleration. By selectively removing these outlying particles through laser scraping (H- + γ → H + e-), this growth can be reduced. This report presents experimental results from both symmetric and asymmetric longitudinal scraping of H⁻ bunches in the Fermilab linac, which were subsequently injected into Booster, and evaluates the broader applicability of this method for future high-intensity accelerator operations.
Paper: MOP035
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP035
About: Received: 14 Aug 2025 — Revised: 14 Aug 2025 — Accepted: 14 Aug 2025 — Issue date: 28 Jan 2026
MOP037
Calculating beam extinction in a pulsed proton beam using FPGA-based peak detection
127
The Mu2e experiment at Fermilab imposes stringent requirements on the elimination of out-of-time beam in its pulsed proton beam, a requirement known as “extinction”. Utilizing a new μTCA-based FPGA data acquisition system, we recorded live particle data from scattered particles incident on an array of quartz Cherenkov radiators and photomultiplier tubes to measure the extinction in the inter-pulse gaps in the pulsed proton beam. Minuscule errors in the derived signal period can make a measurement of the extinction impossible, so after taking a Fourier transform, further optimizations on the period were done based on the assumption that the signal period is stable over the full time of the beam spill while it is being resonantly extracted. After these optimizations, the beam extinction was shown to be on the level of 10^3.
Paper: MOP037
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP037
About: Received: 09 Aug 2025 — Revised: 14 Aug 2025 — Accepted: 14 Aug 2025 — Issue date: 28 Jan 2026
Fabrication progress of an RF beam sweeper for purifying rare isotope beams
The RF beam sweeper at ATLAS facility plays a key role in the production of radioactive ion beams by enabling time-of-flight-based separation, thereby improving the purity of in-flight rare isotope beams. The current sweeper operates 6 MHz and achieves a maximum deflecting voltage of 55 kV. However, the enhanced beam capabilities introduced by the Argonne In-flight Ion separator (RAISOR) require a more versatile and higher-performance sweeper. To meet these needs, we are developing an upgraded RF sweeper capable of operating at 6 MHz and 12 MHz, with an improved deflecting voltage of 150 kV. The system employs a resonant circuit architecture incorporating electrode plates, an adjustable coil, and a mechanical sliding switch to facilitate frequency adjustment. In this talk, we will present design considerations and fabrication progress of the new RF sweeper, aimed at supporting next-generation rare isotope beam experiments.
MOP039
Fast adaptive neural control of resonant extraction at Fermilab
131
We present the development of a machine learning (ML) regulation system for third-order resonant beam extraction in the Mu2e experiment at Fermilab. Classical and ML-based controllers have been optimized using semi-analytic simulations and evaluated in terms of regulation performance and training efficiency. We compare several controller architectures and discuss the integration of neural control into an adaptive framework. In addition, we report progress on implementing low-latency, edge-based inference to enable deployment in hardware-constrained environments. This work demonstrates the feasibility and potential advantages of ML-based control for regulating complex, non-stationary systems, with applications extending beyond resonant extraction.
Paper: MOP039
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP039
About: Received: 08 Aug 2025 — Revised: 14 Aug 2025 — Accepted: 14 Aug 2025 — Issue date: 28 Jan 2026
MOP040
Fast beam probe development for longitudinal bunch measurements at UC Davis Crocker Nuclear Laboratory Cyclotron
135
The UC Davis Crocker Nuclear Laboratory (CNL) operates a 76-inch Isochronous Cyclotron dating to the 1960s. Recent experiments have revealed unexplained beam behavior, which cannot be directly measured with the current diagnostics. Direct measurements of the beam in the Cyclotron are challenging due to the harsh environment, including high radiation, strong magnetic fields, RF interference, and spatial constraints. To address this, we are developing a novel beam probe capable of resolving longitudinal bunch structure across 16 positions simultaneously. The fast beam probe consists of a segmented fast plastic scintillator array coupled via fiber optics to external Silicon Photomultipliers (SiPMs), mounted on a radially translating probe. We report on the probe's performance from in-air tests at the general-purpose beamline. The results demonstrate sub-nanosecond resolution, consistent sensitivity across channels, and clear signatures of beam dynamics, establishing the system’s viability for measurements inside the CNL Cyclotron.
Paper: MOP040
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP040
About: Received: 07 Aug 2025 — Revised: 13 Aug 2025 — Accepted: 13 Aug 2025 — Issue date: 28 Jan 2026
Field mapping and alignment procedure for new photoinjector solenoid magnets at the Argonne Wakefield Accelerator
The Argonne Wakefield Accelerator test facility will be upgrading the RF photoinjector with a new symmetrized RF photogun (named G4) in order to increase beam brightness and stability. In conjunction with G4, three new solenoid coils have been commissioned to replace the previous solenoids, with new considerations to preserve field symmetry and combat higher order modes within the coil that could reduce beam quality. We report here on the recent field mapping efforts on the solenoid, as well as discuss how these measurements can be used to aid alignment of the coils during the installation of the new G4 RF photogun.
MOP042
FPGA-based spill regulation system for the Muon Delivery Ring at Fermilab
138
The Muon to Electron Experiment (Mu2e) requires a uniform beam profile from the Muon Delivery Ring to meet their experimental needs. A specialized Spill Regulation System (SRS) has been developed to help achieve consistent spill uniformity. The system is based on a custom-designed carrier board featuring an Arria 10 SoC, capable of executing real-time feedback control. The FPGA processes beam pulses of approximately 200 ns every 1.695 microsecond, allowing for continuous monitoring of the extracted spill intensity through fast bunch integration. The system directly controls three quadrupole magnets, which work in conjunction with sextupole magnets to achieve third-order resonant extraction. Furthermore, the board interfaces with Fermilab’s Accelerator Control Network (ACNET), enabling operators to modify spill regulation settings in real-time via the control network while providing diagnostic waveforms. These waveforms help operators monitor the process and fine-tune the feedback mechanisms. This paper presents an overview of the board's architecture and its initial progress toward regulating beam extraction. This initial version of the regulation system aims to evaluate baseline performance to inform future system improvements.
Paper: MOP042
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP042
About: Received: 08 Aug 2025 — Revised: 13 Aug 2025 — Accepted: 14 Aug 2025 — Issue date: 28 Jan 2026
MOP043
FPGA implementation of a digital signal component separator and a disturbance compensator for the LANSCE 805 MHz solid-state high power RF amplifier
142
Because of aging, and product discontinuity, LANSCE is investigating the replacement of high power RF amplifiers. A promising candidate is the GaN solid-state power amplifier (SSPA). For a high drain voltage, the drain power dissipation of SSPA is increased as the operating efficiency becomes low. The outphasing technique provides high efficiency operation of the SSPA. The outphasing amplifier converts one Amplitude Modulation-Phase Modulation(AM-PM) signal to two PM only signals by the signal component separator(SCS), and these PM only signals are amplified by amplifiers linearly. The combination of the amplified PM only signals yields the linear amplification of the AM-PM input signal. In this paper, a digital SCS (DSCS) in In-phase/Quadrature(I/Q) coordinate is proposed. The DSCS is implemented on the Field Programmable Gate Array(FPGA) based LANSCE digital low level RF (DLLRF) control system. In addition, a digital disturbance observer based compensator is implemented to detect and suppress the amplitude and phase disturbances existing on the RF forward paths. The performances of the DSCS and the disturbance compensator are verified on a low power testbench.
Paper: MOP043
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP043
About: Received: 08 Aug 2025 — Revised: 13 Aug 2025 — Accepted: 15 Aug 2025 — Issue date: 28 Jan 2026
MOP044
GTPSA.jl: A SciBmad interface to the generalised truncated power series algebra library
145
A full-featured interface package to the Generalised Truncated Power Series Algebra (GTPSA) library in MAD-NG has been implemented in the Julia programming language. GTPSA performs fast Taylor-mode automatic differentiation (AD) of functions to arbitrary orders in the specified variables and parameters. In particular, GTPSA excels at computing derivatives to high orders (>1) and high numbers of variables/parameters, making it an extremely powerful tool for use in optimization and in computing parametric Taylor maps. This Julia interface offers another simple way of using the GTPSA library, and will be used extensively in the SciBmad accelerator physics software ecosystem. The interface can also be easily called from Python, via the juliacall package. In this paper, we showcase features implemented in the interface package including performance enhancements, and present an example of integrating a GTPSA map using polymorphic integrators already implemented in Julia.
Paper: MOP044
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP044
About: Received: 23 Jul 2025 — Revised: 08 Aug 2025 — Accepted: 09 Aug 2025 — Issue date: 28 Jan 2026
MOP045
HED-Melt: A coupled framework for modeling high-energy-density conditions in accelerators
149
The high-brightness beams used by modern light sources and accelerators present a new challenge for machince protection. These beams, through impacts with beam intercepting components such as collimators, may generate high-energy-density (HED) conditions capable of causing significant damage to machine components. One significant issue in studying these dynamics is that lack of simulation tools which capture all of the physics present. Particle tracking and particle-matter interaction codes are widely used in accelerator design but the is not significant interfacing between the two and few codes are available to simulate the melting and vaporization seen in some beam strikes. HED-Melt (High Energy Density Modeling of ELectron beam impacts Toolkit) is a framework of coupling three physics codes, elegant, fluka, and flash to model the effects of HED conditions in various accelerators components. The toolkit automatically interfaces between the three codes to run a full-physics simulation of HED conditions for a user-defined machine lattice.
Paper: MOP045
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP045
About: Received: 11 Aug 2025 — Revised: 12 Aug 2025 — Accepted: 15 Aug 2025 — Issue date: 28 Jan 2026
High-throughput, low-latency X-ray characterization for attosecond XFEL diagnostics: A heterogeneous approach
SLAC’s LCLS-II delivers attosecond X-ray pulses at high repetition rates, targeting 1 MHz. Meeting this challenge requires hardware-optimized, low-latency pipelines for real-time, single-shot diagnostics. We present a heterogeneous data processing approach for the Multi-Resolution Cookiebox (MRCO) detector—an array of 16 electron time-of-flight spectrometers with tunable flight lenses and dedicated amplifiers for time, angle- and energy-resolved spectroscopy. MRCO full data pipeline integrates analog-digital co-design with FPGA-accelerated algorithms and edge-deployed machine learning to perform denoising, spectral feature extraction, and temporal reconstruction of the X-ray pulses from LCLS-II. FPGA-optimized peak finding algorithms enable online feature extraction while component neural networks—including long short-term memory models and ResNets—are trained on synthetic data to recover attosecond temporal substructure of the X-ray pulses. By co-optimizing algorithm design with traditional and emerging hardware (e.g., Groq inference cards, FPGAs), we achieve high-throughput, low-latency inference suitable for shot tagging and feedback. These efforts represent a state-of-the-art step toward closing the gap to MHz operation and highlight the growing need for deeper algorithm–hardware co-design in attosecond XFEL science.
MOP048
Implementation of a 1550-nm laser system for beam characterization at the Argonne Wakefield Accelerator
153
Accurately recording an electron bunch’s longitudinal profile is an important diagnostic for wakefield accelerators employing shaped bunches to increase transformer ratios. Electro-optic sampling of terahertz radiation from the bunch is an attractive approach due to its non-destructive nature. In preparation for future characterization experiments, the Argonne Wakefield Accelerator test facility has recently installed a 1550 nm laser system, including the necessary support systems to synchronize with the photoinjector laser system at 81.25 MHz. We report here on the initial installation and synchronization demonstrations.
Paper: MOP048
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP048
About: Received: 08 Aug 2025 — Revised: 13 Aug 2025 — Accepted: 14 Aug 2025 — Issue date: 28 Jan 2026
Implementation of a temperature and density monitoring diagnostic for the LANSCE negative ion source
We report on adding a muti-wavelength emission and absorption diagnostic to the Los Alamos Neutron Science Center (LANSCE) H− ion source, a filament/arc driven, multi-cusp, surface conversion system. In this work we are better quantifying our runtime and source recycle processes. The LANSCE source is used in repeated four-week run cycles during the annual six-month run period. Here, we test the hypothesis that real-time monitoring of the plasma temperature and cesium density will provide feedback information to increase run cycle time, optimize H− current, and monitor the source’s health. We have installed system with fiber transport for monitoring the Hα Balmer line absorption strength of excited state hydrogen at 656 nm and the D2 absorption line of cesium at 852 nm. Our measurement and fiber transport to/from the active source provides a nonintrusive method for extracting data from the source’s 750 kV high voltage environment. Collection of TLDS absorption and emission lines from excited states are incorporated into the data collection scheme with a series of narrow-band dichroic mirrors. Our design of a sweeping TLDS allows for collection of emission and absorption data within the same sub-millisecond plasma arc pulse, and the combination of these measurements allows us to monitor the generating hydrogen plasma temperature and cesium density during ion source conditioning and operations.
MOP050
Improve beam brightness with bayesian optimization at the AGS booster injection at BNL
157
Alternating Gradient Synchrotron (AGS) and its Booster serve as part of the injector compound for RHIC and the future EIC at Brookhaven National Laboratory. Injection and early acceleration processes set maximum beam brightness for the collider rings. Such processes have many control parameters and are traditionally optimized empirically by operators. In an effort to streamline the injection processes with machine learning (ML) techniques, we develop and test a Bayesian Optimization (BO) algorithm to automatically tune the Linac to Booster (LtB) transfer line magnets to maximize beam brightness after injection into the Booster. We present experimental results that demonstrate BO can be applied to optimize Booster injection efficiency.
Paper: MOP050
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP050
About: Received: 06 Aug 2025 — Revised: 10 Aug 2025 — Accepted: 10 Aug 2025 — Issue date: 28 Jan 2026
MOP051
Instrumentation for a prototype fusion propulsion system
160
A prototype colliding beam accelerator has been fabricated for the study of a fusion-based propulsion concept for interplanetary exploration. The purpose of this prototype is to demonstrate collider luminosities commensurate with the requirements of this application. While fusion fuels such as p/Li7 and He3/He3 would generate the required thrust characteristics, this prototype currently employs deuterium. Because neutrons are produced via DD fusion with a peak cross section of 0.1 barns, even modest initial luminosities yield event rates suitable for real-time measurements and lifetime monitoring. The proposed luminosity monitor is based on neutron moderation and absorption and subsequent gamma-ray detection. Sodium chloride serves as the moderator, with most neutrons absorbed by chlorine-35 nuclei having a thermal neutron absorption cross section of 43.6 barns. The collider is a linear device employing electrostatic axial confinement and radial focusing. A combination of destructive and nondestructive sensors are employed to monitor various beam parameters such as intensity, energy spectrum, transverse tunes and halo density distribution.
Paper: MOP051
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP051
About: Received: 08 Aug 2025 — Revised: 12 Aug 2025 — Accepted: 14 Aug 2025 — Issue date: 28 Jan 2026
MOP052
Design of a BPM pick-up for the EIC electron storage ring
163
A new beam position monitor (BPM) pick-up, compatible to operate reliably with the high current electron beams foreseen in the 5 - 18 GeV Electron Storage Ring (ESR) of the Electron-Ion Collider (EIC) project, is presented. We discuss a few design options for this button-style BPM pick-up with a focus on output signal levels, position characteristic, and wakefield effects. Regarding the octagonal cross-section geometry of the ESR vacuum chamber, the BPM pick-up analysis relies on numerical methods, here performed using the CST Studio software.
Paper: MOP052
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP052
About: Received: 08 Aug 2025 — Revised: 11 Aug 2025 — Accepted: 15 Aug 2025 — Issue date: 28 Jan 2026
MOP053
Investigation of IPM profile changes with variations in the applied electric field
167
Variations in the applied electric field in the Ionization Profile Monitor (IPM) affects the time of flight for the ionized particles (primarily electrons) which could affect the measured transverse beam profile. In addition, the applied electric field may affect the space charge of the ionized electrons inside the IPM. In this paper, we present an experimental beam study of RHIC IPM profiles, examining the effect of varying applied electric fields. Such a beam study will be helpful to enhance the design of the future IPMs for the Electron-Ion Collider. We analyzed horizontal and vertical profiles of gold and proton beams, comparing measured data with simulations along with the procedure we used for measurement. Potential causes for discrepancies between measured and simulated results are also discussed.
Paper: MOP053
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP053
About: Received: 08 Aug 2025 — Revised: 12 Aug 2025 — Accepted: 15 Aug 2025 — Issue date: 28 Jan 2026
MOP054
Lifetime extension of legacy CEBAF LLRF hardware
171
A significant portion of the Low-Level Radio Frequency (LLRF) hardware in Jefferson Lab’s CEBAF is from the original construction of the facility using 1980’s CAMAC technology. Of the fifty-three zones in CEBAF, thirty-six of them are legacy hardware. The age of the legacy system has led to difficulties in maintaining the hardware due to parts going obsolete without suitable drop in replacements. Continued operation of the legacy system is required as the installation of LLRF 3.0 systems is costly and cannot be completed in a short period of time with the available resources. The most pressing failure in the legacy system was a failing buffer card, which is responsible for communication between the EPICs network and individual RF control modules. A new buffer card was designed as a transparent, drop in, replacement so that upgrades are simply a matter of swapping the existing legacy hardware. This buffer card upgrades a single point failure component and promises to extend the operable lifetime of CEBAF’s legacy systems.
Paper: MOP054
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP054
About: Received: 07 Aug 2025 — Revised: 13 Aug 2025 — Accepted: 14 Aug 2025 — Issue date: 28 Jan 2026
MOP055
Low-charge, high-resolution beamline preparation for the nanopatterned microbunching experiment at Argonne Wakefield Accelerator
173
The emittance exchange (EEX) beamline at the Argonne Wakefield Accelerator (AWA) is designed to transfer properties of an electron beam phase space between the transverse and longitudinal planes. Recently, it has been proposed this beamline could be used to convert a microscale transverse modulation created by a TEM grid into a microbunch train in the longitudinal plane. Such a technique would be useful for obtaining nano-scale microbunching that does not rely on the sensitive process of FEL gain. This new approach has been proposed to enable development of a compact free-electron laser at Arizona State, greatly reducing size and cost compared with existing short wavelength FELs. To perform an exploratory demonstration of this concept at AWA, this experiment requires low normalized emittance (~50 nm·rad), low charge (~1pC) electron bunches, and transverse diagnostics with high-resolution (1-3 microns) and high-light-collection to resolve the modulation on the electron beam. This report will give a progress update on preparing the necessary beams and diagnostics at AWA for an emittance exchange experiment that would produce 100s of nm scale microbunches.
Paper: MOP055
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP055
About: Received: 08 Aug 2025 — Revised: 12 Aug 2025 — Accepted: 14 Aug 2025 — Issue date: 28 Jan 2026
MOP056
Machine learning assisted Bayesian calibration of accelerator digital twin from orbit response data
177
Digital twins of particle accelerators are used to plan and control operations and design data collection campaigns. However, a digital twin relies on parameters that are hard to measure directly, e.g., magnet alignments, power supply transfer functions, magnet nonlinearities, and stray fields. These parameters can be constrained by beam position and profile measurements. We use Bayesian statistical inference to estimate the parameters, and their uncertainties, probabilistically by calibrating the Bmad digital twin to beam measurements. The inference is computationally accelerated using a machine learning emulator of the physical accelerator digital twin trained to a perturbed-parameter ensemble of Bmad simulations. The result is a joint posterior distribution over parameters (control currents, individual magnet transfer function coefficients, and beam monitor errors) which is propagated to uncertainties in predicted beam positions and profiles, which we validate against beam responses measured at the AGS booster at Brookhaven National Laboratory.
Paper: MOP056
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP056
About: Received: 08 Aug 2025 — Revised: 10 Aug 2025 — Accepted: 10 Aug 2025 — Issue date: 28 Jan 2026
MOP057
Machine learning at the Spallation Neutron Source accelerator and target
181
We describe the ongoing efforts to apply Machine Learning techniques to improve the performance of our accelerator and target. Specially, we are looking to minimize halo beam losses in the absence of a proper physics model, automatically detect and log anomalies in the target support systems such as cooling, and detect and prevent errant beam pulses in the linac. We also describe the infrastructure we use to acquire and stream data to the GPU cluster for training, our code development cycle, and edge computing for model inference. To minimize halo beam losses, we use a Reinforcement Learning technique tested on a virtual accelerator. The target anomaly detection is trained on archived data using incomplete physics models and is made part of the existing target reporting system. The errant beam prevention analyzes beam current and beam phase waveforms as well as accelerator configuration data to predict errant pulses. We also develop continual learning to adapt to changes in the accelerator.
Paper: MOP057
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP057
About: Received: 08 Aug 2025 — Revised: 14 Aug 2025 — Accepted: 14 Aug 2025 — Issue date: 28 Jan 2026
Machine learning-based reduced-order encoding of 6D particle phase space for accelerators
State-of-the-art simulation of accelerator facilities such as Linac Coherent Light Source (LCLS) involves modeling charged particle dynamics in six-dimensional (6D) phase space under the influence of nonlinear collective effects, including space charge and coherent synchrotron radiation (CSR). Accurately capturing these effects typically requires simulating hundreds of thousands of macroparticles, resulting in significant computational cost in both time and memory. This becomes a bottleneck for downstream tasks such as uncertainty quantification (UQ), model calibration, optimization, and control, which require multiple simulations. These challenges motivate the development of low-dimensional, lightweight surrogate models for accelerators, capable of enabling rapid predictions. However, the high dimensionality of the 6D phase space poses a major obstacle. In this work, we present a machine-learning-based approach for reduced-order encoding of high-dimensional particle phase-space data using autoencoders. In our approach, we learn low-dimensional latent representations that preserve the geometric and physical structure of the original beam distribution, enabling effective compression while retaining essential features. We evaluate this approach on datasets generated using the Bmad particle tracking library, demonstrating its potential as a foundation for fast surrogate modeling, differentiable simulations, and accelerator optimization workflows.
MOP059
Machine learning-enhanced infrared imaging for temperature anomaly detection in power supplies
185
The performance of particle accelerators is critically dependent on the reliability of their power supplies, which can number in the thousands in many facilities. In this work, we present a method for monitoring temperature anomalies in power supplies using infrared (IR) imaging. By applying various machine learning algorithms to the IR imaging data, we develop a reliable anomaly detection system that can improve the uptime of accelerator facilities. This approach enables early detection of potential issues, facilitating predictive maintenance and enhancing overall operational efficiency.
Paper: MOP059
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP059
About: Received: 08 Aug 2025 — Revised: 11 Aug 2025 — Accepted: 12 Aug 2025 — Issue date: 28 Jan 2026
Micro-fabricated photoconductive sampling devices for electron beam field measurements
Achieving high-precision, in situ measurements of electric fields is a critical challenge in ultrafast science and accelerator diagnostics. We are developing an approach using photoconductive sampling with micro-fabricated devices to map electron beam fields with unprecedented spatiotemporal resolution. This technique enables the first direct 3D vector field measurements of electron beams, offering valuable insights into collective effects such as coherent synchrotron radiation and other phenomena impacting beam quality. These low-cost, highly flexible devices present a pathway to enhancing our understanding of beam dynamics and reducing transient effects that degrade beam quality. The devices will be initially tested on the ultrafast x-ray beamline at LCLS, and could be adapted as a diagnostic tool across other SLAC user facilities. Beyond diagnostics, this approach will also help in advancing studies of ultrafast charge transport and unlocking new science in attosecond solid-state physics.
MOP061
Mitigating IDVC thermal deformation with mechanical constraint for reliable ID minimum gap operation
189
Premature activation of the insertion device (ID) minimum-gap limit switches was observed during beamline commissioning at the Advanced Photon Source Upgrade (APSU). This issue was traced to vertical deformation of the insertion device vacuum chamber (IDVC) due to temperature differences with its strongback. Direct measurements of temperature and vertical displacement of IDVC in a selected sector of the APS storage ring confirmed this effect, and simulations successfully reproduced the thermal deformation mechanism. To address the issue, we developed a simple mechanical constraint to limit the vertical displacement, rather than actively compensating for the temperature difference through enhanced heat transfer. This paper reports the investigations, proposed mechanical solution, simulation, and measurement validation after its installation. Post-installation tests successfully demonstrated its effectiveness, allowing the IDs to reach the minimum gap without triggering the limit switch.
Paper: MOP061
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP061
About: Received: 07 Aug 2025 — Revised: 16 Aug 2025 — Accepted: 16 Aug 2025 — Issue date: 28 Jan 2026
Modeling of a high-current injector for beam optimization
End-to-end simulations of intense relativistic electron beams generated by linear induction accelerators (LIA) often involve two-step processes whereby the beam creation is simulated using particle-in-cell (PIC) methods before a handoff to less computationally-expensive methods, e.g. beam envelope solvers, to determine sufficiently robust beam tunes. Because of this hand-off, fields that affect the PIC simulation of the A-K gap region are usually untouched during the tuning process. To allow for magnetic guide field optimization including magnets close to the A-K gap, a machine learning model of an LIA injector system is under development to allow for rapid end-to-end simulations of the electron beam for use in beam optimization problems, e.g. automated magnetic transport field tuning.
MOP064
Online accelerator modeling with two controls systems at FACET-II
193
FACET-II is a unique experimental facility housed in 1 km of the original Stanford Linear Accelerator tunnel. Multiple generations of hardware are still in use, as are two generations of software controls. A majority of subsystems (RF, magnets, timing, etc.) have their controls split across both ecosystems. Three software layers, including a newly-developed online modeling infrastructure, bridge this gap to form a unified high-level abstraction of the accelerator used for data analysis and as a foundation to develop control-room physics applications. We discuss the implementation of this infrastructure and some downstream programs.
Paper: MOP064
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP064
About: Received: 07 Aug 2025 — Revised: 13 Aug 2025 — Accepted: 14 Aug 2025 — Issue date: 28 Jan 2026
MOP065
Integrating simulation and machine learning for Proton Storage Ring beam analysis
196
The Proton Storage Ring (PSR) at the Los Alamos Neutron Science Center (LANSCE) accumulates a 625-μs-long beam and compresses it into a 290-ns-long (base-to-base) short pulse for delivery to the Lujan Center. Due to its high-intensity operation, the PSR also functions as a highly-sensitive mass spectrometer for the entire accelerator complex. Changes in PSR beam losses are more responsive to linac drifts than any other diagnostic system, making continuous monitoring and characterization of the PSR critical to overall performance. Currently, PSR operation is primarily guided by beam loss signals, while key physics parameters—such as the betatron tune, closed orbit, and injection offsets—are typically measured only once per day. Furthermore, Beam Position Monitors (BPMs) can only provide meaningful data a single 290-ns-long injection, requiring dedicated machine time and resulting in operational downtime. However, recent upgrades to both the data acquisition and chopper systems now enable continuous measurements during standard operation. In this work, we employ a Convolutional Neural Network (CNN) trained on simulated data to infer critical beam parameters in real-time. This approach will be tested and implemented during the 2025 run cycle to enable online monitoring and improved control of PSR beam dynamics.
Paper: MOP065
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP065
About: Received: 07 Aug 2025 — Revised: 13 Aug 2025 — Accepted: 13 Aug 2025 — Issue date: 28 Jan 2026
MOP066
Online multi-objective Bayesian optimization of injection efficiency and beam lifetime with skew quadrupoles at NSLS-II
199
At NSLS-II, the vertical emittance of electron beam is typically blown up to ~30 pm with a coupling wave to increase beam lifetime during user operation. As more and more insertion devices are added to the storage ring, injection efficiency to the ring drops noticeably in certain machine states, apparently due to degraded dynamic apertures. To help alleviate this issue, we have recently performed online multi-objective Bayesian optimization to increase injection efficiency while maintaining beam lifetime, by adjusting the strengths of 15 skew quadrupoles in non-dispersive sections. We report the results of this optimization effort.
Paper: MOP066
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP066
About: Received: 08 Aug 2025 — Revised: 12 Aug 2025 — Accepted: 14 Aug 2025 — Issue date: 28 Jan 2026
MOP068
Oscillation data analysis during the LCLS-II commissioning at SLAC
203
Analyzing the betatron oscillation of a beam is mainly used to find focusing errors in the lattice, like quadrupole errors. The generated trajectory differences can be compared with the design lattice or the current machine lattice where some magnets have been changed for different purposes or accidentally. Each method has different advantages and disadvantages like finding a quadrupole which got turned off by mistake won't be discovered with the current lattice method, while matching quadrupoles errors (which get tuned away from design) are harder to identify with the design lattice comparison. Besides lattice errors BPM (Beam Position Monitor) problems can be found too. Interpreting the data can have many pitfalls, some will be explained.
Paper: MOP068
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP068
About: Received: 08 Aug 2025 — Revised: 13 Aug 2025 — Accepted: 14 Aug 2025 — Issue date: 28 Jan 2026
MOP069
New ACE3P capabilities and code integration of ACE3P with Geant4 and Lume
206
The Advanced Computational Electromagnetic 3D Parallel simulation suite (ACE3P), developed by SLAC National Accelerator Laboratory, is a state-of-the-art multi-physics toolkit designed for virtual prototyping of accelerator and RF components. Leveraging over two decades of development, ACE3P integrates advanced physics modeling, including thermal and structural modeling, capabilities with scalable numerical algorithms to deliver cutting-edge simulations. The suite, comprised of seven application modules, utilizes high-order curved finite element methods to achieve high accuracy while enabling fast simulations for large-scale problems. Two recent advancements include the integration with Geant4, for radiation studies and positron source generation, and the development of LUME-ACE3P, built on the Python framework of the LUME project*, which streamlines parameter sweeps and optimization tasks. Furthermore, recent code optimizations have increased the performance of ACE3P for large-scale computations on modern supercomputers. We present a real accelerator project study with ACE3P to demonstrate its scalability and efficiency conducted on NERSC supercomputers.
Paper: MOP069
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP069
About: Received: 08 Aug 2025 — Revised: 14 Aug 2025 — Accepted: 15 Aug 2025 — Issue date: 28 Jan 2026
MOP070
Performance optimization of the IOTA duoplasmatron proton source
210
We present results from online optimization studies of a duoplasmatron ion source designed to produce 50 keV protons for acceleration to 2.5 MeV and subsequent injection into the Integrable Optics Test Accelerator (IOTA) at Fermilab. Using a Bayesian exploration technique, we developed multi-parameter models of the source’s proton current and employed these models to optimize its performance. Depending on the spectrometer configuration used to isolate the proton beam and the chosen optimization objective, we identified three candidate operating points, achieving normalized 50 % emittances between 0.57 μm and 1.3 μm and a maximum proton current of 14.5 ± 0.6 mA.
Paper: MOP070
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP070
About: Received: 10 Aug 2025 — Revised: 12 Aug 2025 — Accepted: 13 Aug 2025 — Issue date: 28 Jan 2026
Phase space reconstruction of beams affected by coherent synchrotron radiation
Coherent synchrotron radiation (CSR) is a limiting effect in linear accelerators with dispersive elements due to its contribution to projected transverse emittance growth. This effect becomes a limitation for highly compressed beams. Even though CSR-induced projected emittance growth has been widely studied, conventional measurement techniques are not detailed enough to resolve the multi-dimensional structure of the beam, namely the different translations and rotations of transverse phase space slices throughout the longitudinal coordinate. In this work, we use a state-of-the-art method to reconstruct the phase space of a beam affected by CSR at the Argonne Wakefield Accelerator Facility. This detailed, efficient and multi-dimensional phase space reconstruction method enables better understanding of the CSR effects in a double dogleg where shielding is limited.
MOP072
Transverse phase space tomography at FACET-II
214
We present recent development of transverse phase space tomographic reconstruction techniques at FACET-II. We present implementation of such techniques in the FACET-II injector, and utilize it to characterize the two-bunch from photocathode configurations. We demonstrate the characterization of two-bunch phase space misalignment and its potential control and application in PWFA experiments. We also characterize the effect of transverse space-charge force by varying two-bunch charge ratio. We also present single-shot and multi-shot tomographic reconstruction of electron spectroscopy image for PWFA-accelerated beam characterization.
Paper: MOP072
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP072
About: Received: 08 Aug 2025 — Revised: 12 Aug 2025 — Accepted: 15 Aug 2025 — Issue date: 28 Jan 2026
MOP073
Physics considerations for a harp system design at the Second Target Station of the Spallation Neutron Source
217
A harp system is being developed for monitoring proton beam profile direct upstream of the proton beam window at the Second Target Station of the Spallation Neutron Source, Oak Ridge National Laboratory. It consists of two sensor planes which have arrays of thin conducting wires aligned vertically and horizontally, respectively. It monitors beam profiles in two transverse directions to the beam axis by measuring the net-charge depositions in the sensor wires, which are caused by ejection of secondary electrons and delta rays driven by electromagnetic interactions with high-energy protons. The net charge deposition in a sensing wire linearly correlates with the number of incident protons on it. This correlation is perturbed when the wire interacts with secondary electrons and delta rays originating from beam-matter interactions in neighboring wires, PBW and residual gases. In this paper, we analyze the physical phenomena that affects the measurement uncertainties of the harp using particle transport simulations.
Paper: MOP073
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP073
About: Received: 06 Aug 2025 — Revised: 13 Aug 2025 — Accepted: 15 Aug 2025 — Issue date: 28 Jan 2026
Physics-coupled Bayesian algorithm for APS-U nonlinear dynamics tuning
The Advanced Photon Source (APS) facility has just completed an upgrade to become one of the world’s brightest storage-ring light sources. Machine learning (ML) methods have seen extensive use during commissioning. One important application was multi-objective tuning of dynamic aperture and lifetime, a complex high-dimensionality task intractable with classic optimization methods. In this work we will discuss novel Bayesian optimization (BO) algorithmic and implementation improvements that enabled this use case. Namely, pre-training and uncertainty-aware simulation priors, dynamic parameter space and acquisition function refinement, and an adaptive wall-time convergence criteria. We will also show results of optimization runs from 10 to 24 dimensions, benchmarking scaling and efficiency as compared to standard MOGA and MGGPO. Given the promising performance, work is proceeding on tighter BO integration into the control room.
MOP075
Detectors and beam monitors based on wide bandgap semiconductors at cryogenic temperatures
221
Wide-bandgap semiconductors, such as single-crystal diamond and sapphire, can be used to measure the flux of passing particles through a particle-induced conductivity effect. We recently demonstrated a diamond-based, electrodeless electron beam halo monitor. This monitor utilized a thin diamond blade placed within an open, high-quality microwave resonator. The blade partially intercepted the beam and changes in the RF properties of the resonator were used to infer beam parameters. To enhance the sensitivity of our semiconductor sensors, we propose two new techniques: (1) biasing the semiconductor sensor to support avalanche multiplication of free carriers, and (2) operating at cryogenic temperatures to reduce intrinsic semiconductor losses and increase the mobility of induced carriers. These techniques are applicable not only to particle beam diagnostics but also to the detection of various types of ionizing radiation.
Paper: MOP075
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP075
About: Received: 01 Aug 2025 — Revised: 10 Aug 2025 — Accepted: 11 Aug 2025 — Issue date: 28 Jan 2026
MOP076
Preliminary study of auto-differentiation algorithm in beam dynamics with stochastic process
225
Modern particle accelerator optimization requires sophisticated computational methods to address the inherently stochastic nature of beam dynamics. This research develops a framework applying AD to SDEs that specifically addresses beam dynamics challenges in particle accelerators, focusing on accurately modeling and optimizing beam behavior in regimes dominated by stochastic processes. By incorporating key physical phenomena such as synchrotron radiation, wakefield effects, and quantum excitation, the framework aims to provide auto differentiation on the figure of merit of the phase space evolution and beam dynamics. The methodology will enable effective optimization method in a dynamic system with stochastic process.
Paper: MOP076
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP076
About: Received: 07 Aug 2025 — Revised: 11 Aug 2025 — Accepted: 12 Aug 2025 — Issue date: 28 Jan 2026
Progress report on the upcoming drive beam photoinjector upgrades at the Argonne Wakefield Accelerator
The Argonne Wakefield Accelerator test facility is dedicated to research on advanced acceleration, beam manipulation, and beam production. With a focus primarily in the development and testing of high-gradient wakefield-accelerator structures, the drive beamline RF photoinjector is capable of delivering high charge (100s of nC) 65 MeV electron bunch trains. We present the planned upgrades to the drive photoinjector aimed at increasing both beam brightness and stability, and report on the current progress for the first phase of the upgrade and upcoming RF gun installation.
MOP078
Proposal to measure bunch lengths using a pulse dilation photomultiplier tube
229
Electron bunches in storage rings are typically short (~100 ps) and separated by long periods of time (>2 ns). A pulse dilation photomultiplier tube offers a new way of measuring high bandwidth optical pulses using low bandwidth oscilloscopes. Experiments performed by others have demonstrated a temporal resolution of 12 ps, meeting requirements for electron bunches expected for the Advanced Photon Source Upgrade. Compared to electrooptical streak cameras, we think that this may be a preferred technique for measuring the longitudinal profile of bunches in electron storage rings.
Paper: MOP078
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP078
About: Received: 08 Aug 2025 — Revised: 11 Aug 2025 — Accepted: 12 Aug 2025 — Issue date: 28 Jan 2026
MOP079
Proposal to streak optical pulses using a solid state optical deflector
232
Streak cameras are flexible cameras used to measure the temporal profile of optical pulses. Streak cameras have been employed to measure the longitudinal beam profile on accelerators around the world. In the present work, we highlight a potential alternative to a new streak camera. We consider particularly linear (Pockels) and quadratic (Kerr) electro-optical nonlinearity solid-state streaking systems. Of the possible solid state systems, we motivate the potential advantages of a Potassium Tantalum Niobate KTa1-xNbxO3 crystal as a photon beam deflector to measure the longitudinal profiles of electron beams in accelerators.
Paper: MOP079
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP079
About: Received: 08 Aug 2025 — Revised: 12 Aug 2025 — Accepted: 12 Aug 2025 — Issue date: 28 Jan 2026
Recent beam test results of RadiaBeam’s multi-dimensional bunch shape monitor at SNS facility
Accurate measurement of longitudinal beam parameters is critical for optimizing high-intensity linear accelerators, yet remains difficult for non-relativistic proton and ion beams. The Bunch Shape Monitor (BSM) is a diagnostic device designed to measure the longitudinal profile of charged particle beams. It operates by inserting a thin wire into the beam path, which emits secondary electrons upon interaction with the main beam. These electrons retain the temporal charge distribution information of the primary beam, which is then converted into a spatial distribution using an RF deflector. Existing BSM models suffer from low electron collection efficiency and are limited to one-dimensional measurements of the longitudinal phase coordinate. To address these limitations, RadiaBeam has developed a next-generation BSM prototype featuring a refined focusing field between the target wire and entrance slit to increase secondary electron collection efficiency, an improved RF deflector for greater temporal resolution and linearity, and an upgraded movable mechanism to enable both longitudinal and transverse profile measurements. In this talk, we will present recent beam test results performed at the Spallation Neutron Source (SNS), highlighting improvements to the BSM based on insights from initial experimental data. Additionally, we will discuss further modifications to the BSM needed for compatibility with other facilities, such as PIP-II at Fermilab.
Resolution enhancement of double-differential spectrometer images
By pairing the effects of a transverse deflecting cavity and dipole magnet, a beam's longitudinal phase space (LPS) can be imaged on a screen. However, the emittance of the beam, chromatic focusing, and other effects are convolved into the resulting screen image, functionally blurring it, reducing the fidelity of the LPS measurement. Here, we explore the use of both conventional, space-variant deconvolution as well as machine-learning approaches to better resolve the LPS.
MOP083
Resonant cavity for quadrupole moment measurements of heavy ion beams
236
Non-invasive and fast beam emittance measurement is highly demanded for accelerated multi-charge-states heavy ion beams. The driver linac of the Facility for Rare Isotope Beams is the first accelerator intended to accelerate multiple charge states of stripped heavy ion beams and deliver up to 400 kW to the isotope production target. Emittance measurements of, for example, five charge states of uranium beam using conventional wire profile monitors take more than an hour in one location and add up to a few hours throughout the linac. This work presents design studies for a resonant cavity monitor capable of instantaneous measurement of the quadrupole moment of the beam distribution. Coupling with the beam and signal acquisition system, the separation between monopole, dipole, and quadrupole modes of the cavity are discussed.
Paper: MOP083
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP083
About: Received: 08 Aug 2025 — Revised: 12 Aug 2025 — Accepted: 12 Aug 2025 — Issue date: 28 Jan 2026
MOP084
RF characterization of a cryogenic X-band cavity beam position monitor for superconducting undulator applications at SLAC
240
Superconducting undulators (SCUs) have gained significant interest due to their advantages over permanent magnet undulators, including the ability to achieve higher magnetic fields and shorter periods, leading to enhanced photon energy gain. As part of the SCU project at SLAC, an X-band cavity beam position monitor (BPM) has been designed and fabricated. This BPM plays a crucial role in the SCU assembly ensuring precise beam alignment with sub-micron resolution. The BPM incorporates two rectangular cavities for X- and Y-position measurements and a cylindrical reference cavity, all housed within a single copper block. Each cavity is separated by approximately 30 mm, which eliminates crosstalk between channels. The design of each cavity includes a single WR-75 waveguide port with a ceramic window as vacuum-air interface for out-coupling the EM field from the cavity to the external circuit. Additionally, each cavity is equipped with a tuner pin for resonant frequency adjustments. In this work, we report on the RF characterization of the BPM cavities conducted at both room and cryogenic temperatures. A consistent resonant frequency shift of approximately 37 MHz was observed when cooling the cavities from room temperature to 40 K, which is the nominal operating temperature within the undulator cryomodule. These measurements validate the predictions made during the BPM design phase through simulations. We also discuss future plans and possible applications beyond the SCU project.
Paper: MOP084
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP084
About: Received: 07 Aug 2025 — Revised: 10 Aug 2025 — Accepted: 12 Aug 2025 — Issue date: 28 Jan 2026
Rotor-based multileaf collimator for beam shaping
Multileaf collimators (MLC) are versatile tools for beam shaping, both transversely or, when used in conjunction with an emittance exchange (EEX) beamline, longitudinally. The requirement for ultra-high vacuum compatibility introduces significant constraints on the design of a MLC. Here, we present a novel design for a MLC based on stacks of rotors with angularly dependent radii. The use of tabs and slots allow dozens of these rotors to be positioned using a single vacuum feedthrough, dramatically reducing complexity over independently positioned leaves. We discuss other design elements and also the considerations arising from having a volumetric rather than planar beam mask.
MOP086
SEM grid testing at NLCTA in BeamNetUS program
244
We report on the performance of a secondary electron monitor (SEM) grid for determining the transverse profile of an MeV range electron beam tested at SLAC National Accelerator Laboratory’s NLCTA facility. When inserted into the path of the electron beam, secondary electron emission results in a measurable current on the wires that make up the grid. We present measurements using this technique to reconstruct the beam profile. The SEM grid was designed and built by a team of Harvey Mudd College (HMC) undergraduate students and tested at SLAC’s NLCTA facility in collaboration with NCLTA staff as part of the BeamNetUS program. This SEM grid, developed for real-time measurements of an MeV scale electron beam, could have applications in industry and medicine.
Paper: MOP086
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP086
About: Received: 08 Aug 2025 — Revised: 13 Aug 2025 — Accepted: 14 Aug 2025 — Issue date: 28 Jan 2026
MOP087
Status of longitudinal bunch-by-bunch feedback system at the upgraded Advanced Photon Source
248
The upgraded Advanced Photon Source (APS) is using twelve Radio Frequency (RF) cavities from the original APS RF system to compensate for beam energy loss. Undamped higher order modes (HOMs) from these cavities pose a risk of instability under the new APS conditions. Dimtel iGp12 processor-based bunch-by-bunch Longitudinal Feedback (LFB) system is developed to address longitudinal coupled-bunch instabilities caused by HOMs. These instabilities are exacerbated by the reduced synchrotron frequency and faster growth rates in presence of bunch lengthening system. The mitigation strategy involves initially reducing growth rates through precise cavity temperature tuning, followed by employing the LFB system to effectively manage residual growth rates. Resonance cavity temperatures of the HOMs have been characterized under APS conditions, providing a reference for tuning in the upgraded APS operation. The LFB system is designed to operate in both phase and energy sensing modes. This paper presents the feedback configuration, initial commissioning results with phase and energy sensing modes, and the feedback setup for operations.
Paper: MOP087
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP087
About: Received: 12 Aug 2025 — Revised: 12 Aug 2025 — Accepted: 15 Aug 2025 — Issue date: 28 Jan 2026
MOP089
Surrogate model for third-integer resonance extraction at the Fermilab Delivery Ring
251
We present an ongoing work in which a surrogate model is being developed to reproduce the response dynamics of the third-integer resonant extraction process in the Delivery Ring (DR) at Fermilab. This is in pursuit of smoothly extracting circulating beam to the Mu2e Experiment’s production target, whereby the goal is to extract a uniform slice of the circulating 1e12 protons in the DR over 25,000 turns (43 ms). The DR contains 3 harmonic sextupoles that excite a third-integer resonance and three fast, tune-ramping quadrupole magnets that drive the horizontal tune towards the 29/3 resonance. In our initial work, the surrogate model trains on a semi-analytical simulation provided in the same format as live data. Using Reinforcement Learning (and other potential ML methods), the trained surrogate acts as the “environment” in which a simple ML control agent could learn to dynamically adjust the quadrupole ramp at 430 break points within the 43 microsecond spill window. The controller will be hosted on a dedicated Arria 10 FPGA. In this work, we report the accuracy and fidelity of the surrogate model in comparison to the response dynamics of the physics simulator.
Paper: MOP089
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP089
About: Received: 08 Aug 2025 — Revised: 14 Aug 2025 — Accepted: 26 Aug 2025 — Issue date: 28 Jan 2026
MOP090
Synchrotron frequency measurements using bunch by bunch longitudinal feedback system in a storage-ring with higher harmonic cavity
255
The upgraded Advanced Photon Source (APS) features a 1408 MHz superconducting Bunch Lengthening System (BLS) to improve beam lifetime and emittance. The main RF system is significantly affected by ambient 60 Hz-harmonics noise, complicating the measurement of synchrotron frequency under varying higher harmonic cavity conditions. To address this, using Dimtel iGp12 processor-based longitudinal feedback system we developed two methods to measure synchrotron frequency effectively. Our approach involves driving multi-bunch beam modes by considering a span for synchrotron frequency sideband and analyzing mode amplitude changes across the sweep frequency range. The "slow" method scans fixed drive frequencies within a range, recording the beam response at each frequency. The “fast” approach drives the beam with a broadband chirp signal and analyzes the resulting single mode spectrum data. Both methods are tested during beam studies. Synchrotron frequency changes are measured in two setups: First, adjusting BLS voltage manually while keeping beam current constant. Second, BLS voltage varying as a function of decaying beam current. This paper presents, details of the measurement procedure and results from the beam-based machine studies.
Paper: MOP090
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP090
About: Received: 12 Aug 2025 — Revised: 13 Aug 2025 — Accepted: 13 Aug 2025 — Issue date: 28 Jan 2026
MOP091
The beamline steering software for the APS Upgrade (APS-U) Accelerator Storage Ring
258
A new beamline steering software system is being developed for the Advanced Photon Source Upgrade (APS-U) accelerator storage ring. This system comprises three main components: The main steering server, which performs the actual beamline steering; The beamline steering server, which monitors users' steering requests and forwards them to the main steering server; And an operational steering application. The underlying steering functionality is managed by the Data Acquisition (DAQ) PV Group module. This module includes utilities for controlling and monitoring multiple scalar Channel Access (CA) Process Variables (PVs), combining their values into a single PV data object that is served on a specified PVA channel. Users can interact with the PV group either via PVA or through a set of control CA PVs hosted directly by the PV group controller. The new steering software is compatible with any kind of global orbit correction, running independently. It offers significant enhancements over the previous system, including parallelization capabilities and improved efficiency.
Paper: MOP091
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP091
About: Received: 06 Aug 2025 — Revised: 14 Aug 2025 — Accepted: 14 Aug 2025 — Issue date: 28 Jan 2026
MOP092
The control and monitoring system for the APS-U front-end XBPM
261
The Advanced Photon Source Upgrade (APS-U) project aims to enhance the performance and capabilities of the APS, delivering brighter and more coherent x-ray beams to support cutting-edge scientific research. A critical component of this upgrade is the front-end X-ray Beam Position Monitor (XBPM) system, which plays a vital role in ensuring beam stability and precision. This paper presents the design and implementation of the control and monitoring system for the APS-U front-end XBPM. The system integrates advanced hardware and software solutions to achieve real-time monitoring of x-ray beam position. Key features include high-resolution data acquisition, robust signal processing algorithms, and seamless integration with the APS-U control architecture. The system utilizes the Experimental Physics and Industrial Control System (EPICS) input/output controllers (IOCs) to interface with front-end instruments. By leveraging EPICS IOCs, the system achieves high reliability and flexibility.
Paper: MOP092
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP092
About: Received: 07 Aug 2025 — Revised: 15 Aug 2025 — Accepted: 15 Aug 2025 — Issue date: 28 Jan 2026
MOP093
Towards accurate beam sigma matrix determination in a transport line using differentiable simulation
264
Precise characterization of the beam distribution is essential for matching the incoming beam and optimizing injection into storage rings. We present a method to efficiently reconstruct the full 5×5 beam sigma matrix (excluding the time coordinates) at the booster-to-storage-ring (BTS) transport line at the Advanced Photon Source Upgrade (APS-U). Earlier works demonstrated that the beam sigma matrix can be accurately reconstructed using linear transport matrices under the assumption of negligible chromatic effects. However, the presence of chromaticity introduced significant non-linearities and leads to discrepancies from the linear approaches. In this work, we demonstrate a novel approach leveraging Cheetah, a differentiable beam dynamics simulation framework, to enable direct gradient-based optimization of the beam matrix. Initial results shows efficient and accurate reconstruction under both linear and second-order tracking models, providing improved robustness in simulation studies. This method offers a scalable, interpretable, and computationally efficient alternative to black-box methods for beam matrix reconstruction in transport lines in presence of complex effects.
Paper: MOP093
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP093
About: Received: 06 Aug 2025 — Revised: 12 Aug 2025 — Accepted: 13 Aug 2025 — Issue date: 28 Jan 2026
MOP094
Two-stage constrained Bayesian optimization for particle accelerator tuning
268
Particle accelerators are highly complex, non-linear systems that require rapid tuning during operation to meet requirements on beam qualities for applications in different scientific disciplines. Multi-objective Bayesian Optimization (MOBO) has been recently demonstrated at SLAC MeV-UED facility for speeding up online electron beam tunings and obtaining Pareto Fronts giving trade-offs between key beam properties of interest. One challenge in algorithm- based tuning is the alignments of beam through the collimators, screens and timing diagnostics under different system working points. This usually requires trial-and-error based hand tunings and strongly limits the data taking efficiency. Here, we utilize two-stage constrained Bayesian optimizations (CBE-MOBO) for beam tunings at MeV-UED. Instead of directly optimizing objectives of interest, beam property constraints are first modeled in the tuning-measurement joint domain using constrained Bayesian exploration. Based on the information learned, MOBO is then used to efficiently search the parameter space and resulted in dramatically improved valid data efficiency. Our results show potential of CBE-MOBO for autonomous tunings of particle accelerators.
Paper: MOP094
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP094
About: Received: 08 Aug 2025 — Revised: 12 Aug 2025 — Accepted: 12 Aug 2025 — Issue date: 28 Jan 2026
MOP095
Ultra-fast switching utilizing an IVA topology for chopper applications
272
Recent trends in power electronics indicate increasing demand for fast response switching networks with sub nanosecond switching speed at a variety of volt-ages. Gate driving networks meet the desired switching speeds using COTS (Commercial Off-The Shelf) parts. This work describes an IVA (Inductive Voltage Adder) system capable of switching in the single digits of ns with a projected voltage output of 2 kV, using a gate driving topology to drive GaN (Gallium Nitride) HEMTs (High Electron Mobility Transistor). These rapid switching systems are proposed to be used in the LAMP (LANSCE Accelerator Modernization Project) chopper to effectively produce clean beam to select target stations, producing the needed output.
Paper: MOP095
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP095
About: Received: 08 Aug 2025 — Revised: 14 Aug 2025 — Accepted: 14 Aug 2025 — Issue date: 28 Jan 2026
MOP096
Upgrade to fixed and translating scintillation-based loss detector system in the Fermilab Drift Tube Linac
275
The closed-off structure of the Fermilab Drift Tube Linac precludes a robust array of instrumentation from directly monitoring the H- beam that is accelerated from 750 keV to 116 MeV. To improve beam tuning and operational assessment of Drift Tube Linac performance, scintillator-based loss monitors were previously installed along the exterior of the first two accelerating cavities to assess low energy beam losses. Here we present a recent upgrade to the loss monitor system, including significant improvements in analog signal processing to address baseline-interfering noise; digitization of the signals to enable regular operational use and tuning; and a new remote operation upgrade of the translating loss monitor with precise positioning of the loss monitor along its nine-foot track. Data from the fixed and translating detectors collected under varying beam conditions validate the utility of the upgrade.
Paper: MOP096
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP096
About: Received: 08 Aug 2025 — Revised: 11 Aug 2025 — Accepted: 14 Aug 2025 — Issue date: 28 Jan 2026
MOP097
Machine learning-driven computations of 3D Coherent Synchrotron Radiation
279
Calculating the effects of Coherent Synchrotron Radiation (CSR) is one of the most computationally expensive tasks in accelerator physics. Here, we use convolutional neural networks (CNN's), along with a latent conditional diffusion (LCD) model, trained on physics-based simulations to speed up calculations. Specifically, we produce the 3D CSR wakefields generated by electron bunches in circular orbit in the steady-state condition. Two datasets are used for training and testing the models: wakefields generated by three-dimensional Gaussian electron distributions and wakefields from a sum of up to 25 three-dimensional Gaussian distributions. The CNN's are able to accurately produce the 3D wakefields ~250-1000 times faster than the numerical calculations, while the LCD has a gain of a factor of ~34. We also test the extrapolation and out-of-distribution generalization ability of the models. They generalize well on distributions with larger spreads than what they were trained on, but struggle with smaller spreads.
Paper: MOP097
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP097
About: Received: 06 Aug 2025 — Revised: 15 Aug 2025 — Accepted: 15 Aug 2025 — Issue date: 28 Jan 2026
Virtual critical coupling technique for elimination of power reflections in RF cavities
Effective control of power reflections in high-power RF systems is essential for maintaining energy efficiency and protecting system components. Virtual Critical Coupling (VCC) is a novel approach that allows to eliminate reflections by temporally shaping a complex frequency excitation signal in a resonator to ensure that it fully traps all impinging energy. The absorbed energy is stored in the resonator without being dissipated, and it can be released at will. Unlike traditional coupling techniques, this method does not require mechanical modifications. In this talk, we will present VCC experimental results achieved in an S-band standing wave linear accelerator using a custom low-level RF system and a 5 MW klystron. These findings demonstrate a scalable method for improving the efficiency and stability of high-power resonant systems with potential applications in accelerator technology.
MOP099
X-ray inspection for non-invasive real-time beam detection
283
Conventional methods for measuring lower-energy particle beams (<several MeV), such as Faraday cups, moving wire scanners, and scintillators, are invasive and become impractical for higher-energy beams that exceed material tolerances. Current techniques for detecting beam drift often rely on spill radiation monitoring or beam position devices with off-axis electrodes, which can produce unwanted secondary particles. This study investigates a non-invasive X-ray inspection technique for beam characterization. Through simulations, we examine optimal X-ray energies, detector-beam configurations, scattering mechanisms, and profile reconstruction methods. The results demonstrate the feasibility of real-time beam monitoring without interfering with the primary beam path, offering significant benefits for high-energy physics experiments where maintaining beam integrity is essential.
Paper: MOP099
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP099
About: Received: 31 Jul 2025 — Revised: 14 Aug 2025 — Accepted: 14 Aug 2025 — Issue date: 28 Jan 2026
MOP100
First results of the sXmap cavity field emission detection system from inside a cryomodule
287
Field emission (FE) has been one of the limiting factors in achieving high gradients in superconducting RF cavities. While the causes for FE are mostly known (contaminants on the inner cavity surface, dust, gases adsorbed…), identifying the exact location of field emitters has been a challenge. A detection system developed by Kyoto University has been developed to address this task, the sXmap system. This diagnostic device is made of inexpensive sensor strips that wrap around the iris of a multi cell SRF cavity that sense x-rays generated by FE. In this paper we will present the results obtained from a naked 6 cell SRF cavity in a vertical test configuration, and – for the first time – the results obtained from applying the sensor strips to an SRF cavity already installed inside a cryomodule in our test cave at ORNL – SNS.
Paper: MOP100
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP100
About: Received: 08 Aug 2025 — Revised: 13 Aug 2025 — Accepted: 14 Aug 2025 — Issue date: 28 Jan 2026
MOP102
Impedance modeling of in-vacuum undulator with Gaussian process
290
The impedance of in-vacuum undulators (IVUs) significantly affect the broadband impedance and, consequently, the beam dynamics in storage rings. During the IVU design phase, numerous iterative discussions between physicists and engineers are required, often involving extensive simulations of the complete 3D geometry, a few meters long, using limited computational resources. In this paper, we propose training a Gaussian process model with limited simulation data to emulate the physical model. We compare the predictions of the trained model to the simulation data and explore its application in optimizing the IVU design.
Paper: MOP102
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP102
About: Received: 06 Aug 2025 — Revised: 09 Aug 2025 — Accepted: 09 Aug 2025 — Issue date: 28 Jan 2026
MOP103
Online optimizations of NSLS-II Linac and Linac-to-Booster beam lines using machine learning methods
294
The NSLS-II is a cutting-edge 3 GeV storage ring light source around the world. The electron beam is initially accelerated in a linear accelerator to an energy of 170 MeV and subsequently accelerated in a booster synchrotron to a beam energy of 3 GeV. Therefore, the performance of the Linac and the Linac-to-Booster beam lines is imperative for beam injection to the booster. Online optimization is an effective solution to improve accelerator performance when there is degradation. This paper presents the results of online optimization employing a machine learning method.
Paper: MOP103
DOI: reference for this paper: 10.18429/JACoW-NAPAC2025-MOP103
About: Received: 06 Aug 2025 — Revised: 08 Aug 2025 — Accepted: 10 Aug 2025 — Issue date: 28 Jan 2026