In the last two decades, numerical and experimental studies have extensively explored the impact of the space charge on bunched beams in both linear accelerators and storage rings. However, fully accounting for space charge effects over the entire accelerator is computationally intensive, especially in storage rings, where simulations must track beam dynamics over many turns and extended time periods. In many cases, space charge forces cannot be neglected, motivating the development of an alternative computational model. Here, we explore space charge-induced nonlinear dynamics using a model that approximates the Coulomb force by concentrating its effects at discrete locations along the accelerator. This approach enables efficient analyses of the full six-dimensional phase space evolution under space charge effects. Future work will apply this model to further investigate the interplay between space charge and beam-beam interactions in colliders, as well as to assess long-term stability criteria in ring accelerators.

Recent empirical tuning of the Spallation Neutron Source injection system has produced new injection kicker settings, new time-varying waveforms for each of the eight injection magnets forming a closed four-bump in each plane, for the proton accumulator ring. These new settings deliver beam parameters consistent with target requirements for beam size and peak density, and identical RMS beam sizes at upstream diagnostics. However, beam halo has been reduced from previous settings providing the same RMS size, as evidenced by a significant temperature reduction on halo-monitoring thermocouples surrounding the proton beam window that separates the accelerator vacuum from the helium-filled target environment. In this work we use PyORBIT, a PIC code developed at Oak Ridge National Laboratory, to simulate the injection process for the previous settings, and the newly identified working point to gain insight into the likely source of the halo reduction and investigate further improvements to injection tuning.

The 1.7 MV(5SDH-2) tandem accelerator at the Inter-University Accelerator Centre (IUAC) has been playing a major role in advancing research activities in materials science and nuclear physics experiments using various advanced ionbeam characterization techniques. In this work, I present the IBA technique studies such as (a) RBS Analysis of Au and Au/Ag Thin Films for investigating the effects of low energy ion irradiation (8 keV Ni, 10 keV Ar, and 400 keV Ar) for applications in Surface-Enhanced Raman Scattering (SERS) and other technological applications, (b) RBS of Nat/28Si on Au Backing For in-beam γ-ray spectroscopy experiments for detailed compositional analysis and target integrity, (c) Depth Profiling in 4H-SiC by utilizing RBS Channeling to assess disorder and strain induced by Si ion implantation and its recovery post-thermal annealing (d) Hydrogen Detection in α-Fe2O3 Analysis by ERDA techniques to study the reversible hydrogen control of and ferromagnetic anisotropy, highlighting the material’s potential for novel magnetic storage technologies, will be discussed.

The Facility for Rare Isotope Beams (FRIB) SRF linear heavy-ion accelerator is designed to accelerate all ions up to uranium to a maximum beam power of 400 kW. Several beam intercepting devices (BIDs) are essential to the successful operation of the accelerator, including a low power charge selector (LPCS) made of copper containing 0.15% precipitated aluminum oxide by weight called Glidcop Al-15. As FRIB ramps up the primary beam power beyond the current 20 kW level, the charge selector must withstand higher radiation damage rates, typically measured in displacements per atom (dpa). Significant beam induced radiation damage including significant deformation, like swelling, blistering, and cracking has been observed on a recently removed LPCS. We also observed physical features up to about 5.5 mm wide and appear to be deeper than the projected range of any ions. This paper presents the results of Monte Carlo simulations carried out using the Particle and Heavy Ion Transport code System (PHITS), quantifying the total damage dose and ion concentration, etc. Simulating an accurate irradiation history is essential to determining the scope of post irradiation examination (PIE) work.

The Facility for Rare Isotope Beams (FRIB) is a high-power heavy-ion accelerator, completed in April 2022, designed to accelerate heavy ions to energies exceeding 200 MeV per nucleon (MeV/u). These ions collide with a rotating graphite target, while the residual beam is absorbed by a water-cooled static beam dump positioned at a 6-degree angle to the beam path. The current beam dump consists of a machined C18150 copper alloy block, explosion-bonded to AL2219 alloy with precision-machined cooling grooves. Cooling water is supplied through 3D-printed Aluminum 6061 inlet and outlet components, facilitating heat dissipation from the beam stopper. This paper examines the thermal-hydraulic performance of the Mini-Channel Beam Dump (MCBD) under both nominal and off-nominal conditions. The MCBD is designed to handle operational beam power up to 20 kW, with planned optimizations to support a power ramp-up to 30 kW.

This paper presents the design and performance of a linear injector for heavy-ion cancer therapy,utilizing 200 MHz radio frequency quadrupole (RFQ) accelerator combined with two alternating phase focusing (APF) structures.This simplifies the accelerator structure, enhances beam quality,and ensures high accel-eration gradients,making it a pivotal advancement in compact and cost-effective heavy-ion therapy systems.The proposed configuration aims to deliver high-intensity ion beams with enhanced energy efficiency for clinical applications.The system achieves a remarkable output max beam current of 0.2 mA with energy of 7 MeV/u to the downstream synchro-tron for precision cancer therapy.And now the design and fabrication to beam commissioning has been completed, with experimental results confirming that the system meets all predefined specifications.Beam tuning results demonstrate that the injector reliably delivers beams meeting the target specifications a peak current of 0.2 mA and energy of 7 MeV/u.These achievements validate the technical robustness of the proposed configuration and mark a pivotal advancement in the deployment of heavy-ion accelerators for clinical cancer treatment

A superconducting radio-frequency photo-injector cryomodule is being developed for the high-energy upgrade of the Linac Coherent Light Source (LCLS-II-HE). This effort is a collaboration between the Facility for Rare Isotope Beams at Michigan State University (MSU), Argonne National Laboratory, Helmholtz-Zentrum Dresden-Rossendorf, and SLAC National Accelerator Laboratory. The cryomodule features a 185.7 MHz superconducting quarter-wave resonator (QWR) designed to operate with an RF electric field of 30 MV/m at the photo-cathode. Mechanical vibrations must be controlled for operation with stable amplitude and phase. The first prototype cryomodule was cold-tested at MSU with a QWR, fundamental power coupler, tuner, and cathode stalk. In the cold test, we observed microphonics that made it difficult to control the RF phase at high gradient. The cryogenic circuit was identified as a likely culprit. This paper presents our studies of microphonics during the cryomodule cold test and follow-up investigations at room temperature. Our findings provided valuable feedback for modifications to the cryogenic circuit and a successful second cold test of the cryomodule.

The Facility for Rare Isotope Beams (FRIB) energy upgrade to 400 MeV/u or higher will be accomplished with the addition of 11 cryomodules containing beta = 0.65 elliptical cavities to the FRIB linear accelerator (linac). The fundamental power coupler (FPC) is a continuous wave (CW) coaxial design delivering 15 kW of forward power at 644 MHz with an accelerating gradient of 17.5 MV/m and an external Q range of 7.7e6 to 3.4e7 corresponding to a 5 mm bellows stroke in either direction from its neutral position. The FPC design includes both warm and cold radiofrequency (RF) windows. The cold RF window is encompassed by a cooling jacket supplied with helium at 55 K. This provides conductive cooling to the central antenna from the outer conductor, across the ceramic portion, to the inner conductor, with the aim of minimizing heat input to the liquid helium at 2 K surrounding the superconducting niobium cavity. A coupled self-consistent RF-thermal analysis of the FPC operating with FRIB parameters and materials is presented here.

Since its beginning ATLAS has had both Faraday Cups to measure beam current, and Beam Profile Monitors (BPM) to trace the beam profile. However only the Faraday Cups are used to perform objective beam measurements during tuning and delivery, because cups block the beam during measurements. ATLAS has approximately 41 BPMs which utilize a helically wound wire that continuously sweeps the Y and X profile but does not block beam. The output of these BPMs is sent through a series of multiplexers to an oscilloscope in the control room where operators can see the Y-X sweeps in real-time, as well as capture the waveform on-demand. To make the BPMs more useful for everyday beamline operations, a tighter coupling of the BPMs to the control system is required. The first step is to continuously capture the BPM signal by the control system. Once continuous capture is implemented, software tools to store, analyze, and display key metrics from the BPMs are required to make use of the data. The system would primarily be used as a minimally-invasive approximation of continuous real-time beam current monitor, capable of measuring light ions.

Commercially available cryocoolers typically provide about 2 Watts of cooling at 4.5 K. The ANL Physics Division accelerator group has been testing a new two stage Gifford-McMahon/Joule-Thomson (GM-JT) cryocooler from Sumitomo Heavy Industries. In tests at both RadiaBeam and Argonne the measured cooling capacity is approximately 9.5 Watts at 4.5 K. The cryocooler has also been used to condense helium at approximately 4.3 K at a rate of about 0.4 L/hr into a small helium container. We report here on the experimental hardware used to perform these measurements and discuss the data. The device appears to be an excellent complement to new low-loss Nb3Sn cavities under development at ANL and elsewhere. We comment on this application and the outlook for future uses of the device in ATLAS and elsewhere.

The FRIB (Facility for Rare Isotope Beams) CW linac is based on 326 superconducting cavities, a normal conducting RFQ, and eight normal conducting bunching cavities. Five unique designs were developed for a 40.25-MHz Multi-Harmonic buncher (MHB), 80.5-MHz quarter-wave cavity MEBT bunchers, 161-MHz H-type cavity bunchers, 322-MHz H-type bunchers, and a quarter-wave 161-MHz buncher for a ReAccelerator. The cavities are made of high-purity copper using high-temperature furnace brazing. They are equipped with motorized tuners for real-time frequency control. An efficient water cooling is provided for CW operation. We have developed and applied a multi-step brazing technique to achieve high dimensional accuracy, reliable RF contacts, and accommodate large stainless steel-to-copper joints. The paper will cover the main parameters for each type of bunchers, their design/fabrication, cooling design, RF contact design/effectiveness, tuning process, brazing design and fabrication challenges, coupler design, copper-to-stainless steel transitions, etc. The operation status of these bunchers will also be discussed.

This paper proposes a modular all-SiC design for accelerator pulsed power systems. A unipolar frequency-doubled hybrid SPWM modulation strategy is developed for the front-end PWM rectifier, eliminating zero-crossing distortion (verified by Fourier analysis) and achieving 2.8% THD. A hybrid analog-digital control architecture combines analog control (front-stage rectification and phase-shifted full-bridge) for dynamic response with digital H-bridge control for algorithm flexibility. The comprehensive soft-switching scheme integrates: 1) front-stage resistor-relay coordination, 2) intermediate-stage LC-resonant ZVS, and 3) digital ramp-controlled commutation. An optimized SiC MOSFET driver circuit with active clamping and RC snubber suppresses voltage spikes by 43% while balancing switching dynamics. This multi-level integration enhances modularity through component consolidation and thermal optimization, achieving 96.2% peak efficiency and 30% power density improvement. The design establishes a technical foundation for high-repetition-frequency, high-power applications.

A prototype Canadian compact accelerator-driven neutron source (PC-CANS) is proposed for installation at the University of Windsor. The source is based on a high-intensity compact proton RF accelerator that delivers an average current of 10 mA of protons at 10 MeV to the target. The accelerator consists of a short radio frequency quadrupole (RFQ), followed by an efficient drift tube Linac (DTL) structure. Different variants of DTL were investigated for our studies including the Alvarez TM010 structure and various H-mode structures using both negative synchronous phase and KONUS beam dynamics all at 352.2MHz. For completeness an alternate phase focusing (APF) design was also included in the study. Details of the beam dynamics of a high intensity proton APF Linac are presented in this paper.

Recently, the Institute for Rare Isotope Science (IRIS, previously RISP) in the Institute for Basic Science (IBS), Daejeon, South Korea, finished the first beam commissioning for operating of low-energy superconducting linear accelerator (SCL3). SCL3 is composed of two types of cavity, quarter wave resonator (QWR) which has 81.25MHz RF frequency and half wave resonator (HWR) which has 162.5MHz RF frequency. During operation, RF control was very complicated due to many issues including mechanical vibrations coming from vacuum pump, cryogenic valve, or undefined source. In this paper, we will discuss the SCL3 mechanical vibration data measured by a laser doppler vibrometer (LDV). In addition, the mechanical vibration of SCL3 cryogenic components such as transfer lines and supports will be also described.

Multi-reflection time-of-flight (MR-ToF) devices have arisen as indispensable tools at radioactive ion beam (RIB) facilities. These electrostatic ion beam traps act as highly-selective mass separators providing purified ion beams to subsequent experiments as well as high-precision mass spectrometers enabling mass measurements of short-lived nuclei. Efforts are ongoing to push the limits of these devices, enabling higher resolving power and/or ion throughput. State-of-the-art devices operate with a few keV of beam energy, however simulations detail the need to pursue higher energies [*]. To this end, a high-voltage MR-ToF device has been designed for the Facility for Rare Isotope Beams (FRIB) enabling both high mass resolving power and high ion throughput. Such a device will enable precision mass measurements of short-lived ions as well as the delivery of pure high-intensity beams to subsequent experiments in the stopped and reaccelerated beam areas at FRIB. [*] F. M. Maier et al., NIMA 1056, 168545 (2023)

To meet the beam power requirements of 400 KW for heavy ions at the Facility for Rare Isotope Beams (FRIB), the Electron Cyclotron Resonance (ECR) Ion Source needs to operate at a full 28 GHz radio frequency. The ECR magnet is required to generate a corresponding stable high magnetic field, which is a superposition of the solenoid field and the radial sextupole field. A precise alignment between the magnet and the plasma chamber is required to reduce the differences in the six weak field positions on the chamber wall, thereby reducing local overheating. In this study, a 3D magnetic model was developed to analyze the electromagnetic (EM) performance of the magnet. This paper also introduced a tailored mapper designed to scan the 3D field map of the magnet. From the high harmonic analysis results, the misalignment between the magnetic center and the beamline was calculated, and the subsequent position adjustment was made with the support link control. The azimuthal angle and axial position of the six weak field were estimated at various operating scenarios, providing guidance to improve the design of the plasma chamber for high-power ECR beam operation.

JuTrack is a Julia-based accelerator modeling and tracking package that utilizes compiler-level automatic differentiation (AD) to enable fast and accurate derivative calculations. While JuTrack provides a solid foundation for beam dynamics simulations, its capabilities must be extended to support the Facility for Rare Isotopes (FRIB) linac. This includes modeling heavy-ion linac accelerator components such as the liquid-lithium charge stripper, which facilitates efficient acceleration by remove electrons from heavy isotopes, and incorporating multi-charge state acceleration tracking, which allows for charge-dependent beam dynamics. These extensions address challenges such as the beam matching and optimization of multi charge state through various accelerating structures and beam-material interaction modeling while maintaining the auto differentiation capability. This work focuses on adapting JuTrack to incorporate these elements, enhancing its online modeling abilities. We present modifications to JuTrack’s framework and demonstrate their performance in FRIB simulations.

Cameras observing scintillating viewers provide a valuable tool for tuning heavy ion beams. The close placement of these cameras near intense stray neutron and ion radiation, particularly at elements intercepting the primary beam, presents a unique reliability challenge. Commercial solutions are sparse, expensive, and sometimes tightly regulated. We present common failure modes observed at FRIB and propose solutions to extend the lifespan of unspecialized industrial cameras using consumer-grade hardware and open-source software.

Physics application software plays a crucial role in the tuning and operation of the FRIB accelerator. Development began long before the initial commissioning, and with real beam operations, numerous new applications have been created and refined through collaboration between engineers and physicists. These efforts have significantly enhanced beam tuning efficiency and delivery for experiments. This paper provides an overview of the current state of software development, highlights key applications, and outlines the roadmap for future advancements.

An approach to ion beam emittance calculation using code to automate the calibration, capture, and processing of beam images from the ATLAS Pepper Pot system. System calibration and emittance calculations are performed using code designed to minimize user interaction (single button operation) and maximize accuracy by clean processing (noise filtering and automated adaptable beam spot recognition).

Chopper systems are typically used to provide beam time structure and ensure the safety of accelerator operations by deflecting the beam away. To meet the strict beam stopping time requirements of the China Initiative Accelerator Driven System (CiADS), an E × B chopper design has been developed based on a permanent magnet and an electrostatic deflection plate. In this paper, the physical design of the chopper system is detailed, and each component of the chopper is optimized through simulation analysis. Finally, the feasibility of the chopper system is validated through multi-particle simulations and error analysis.

The Facility for Rare Isotope Beams signifies a major advancement in rare isotope beams for research. Delivering heavy and exotic rare isotope beams is accomplished with the Advanced Rare Isotope Separator (ARIS), which creates, purifies and transports radioactive beams. These secondary beams can range from hydrogen to uranium. Every RIB is carefully planned, produced and characterized by ARIS’s system of diagnostics, detectors and data acquisition (DAQ). ARIS detectors can measure the time of flight, energy loss, charge, gamma-rays and position of the species in the beam, allowing the identity, rate, purity, energy and emittance of each rare isotope to be accurately quantified. The needs of each experiment drive the requirement for tuning, to achieve the desired RIB properties for diverse experiments. In this presentation, the current ARIS system of scintillators, PPACs (parallel plate avalanche counters), silicon and gamma-ray detectors, and associated DAQ will be discussed. Furthermore, the ARIS detector system will undergo upgrades to support the main LINAC upgrades from the current 20kW, and these upcoming challenges and changes to detectors and DAQ will be included as well.

The Facility for Rare Isotopes Beams (FRIB) enables groundbreaking research in nuclear physics, astrophysics, and fundamental interactions, as well as the societal applications of this work. Critical to the science program at FRIB is the Advanced Rare Isotope Separator (ARIS), which separates, identifies, and purifies fragments produced via projectile fragmentation and fission using a variety of beamline elements, including eight superconducting dipole magnets. An accurate magnetic rigidity calibration of these dipole magnets is crucial for obtaining peak fragment yields with optimal transport conditions in minimal time and informing simulations of fragment separator experiments. This work reports on the use of the FRIB linear accelerator to provide a U-238 beam of known energy, with accuracy of 0.1%. Charge states of the beam, formed in a thin foil can then be used to calibrate the ARIS dipole field vs bend radius over a range of rigidities. Due to saturation of the iron in the dipoles, the field vs bend radius curve is not linear and deviates significantly once the central field is above 1.5 T. Details of the procedure and results will be presented.

In 2018, the Argonne Tandem Linac Accelerator System (ATLAS) expanded its ability to produce and select radioactive in-flight beams through transfer reactions with the addition of a magnetic chicane for beam momentum selection referred to as the Radioactive Ion Separator or RAISOR. The ATLAS in-flight system consists of a production target positioned immediately upstream of RAISOR, followed by an RF sweeper to further refine beam purity. In this contribution, we present our experience operating the ATLAS in-flight system, operational and facility improvements, current limitations, and upgrade plans.