Frontiers in nuclear physics and nuclear astrophysics center on understanding nuclei far from stability, the limits of nuclear matter, and the nuclear reactions that power stellar evolution and explosive phenomena across the Universe. Progress in these fields increasingly relies on high-intensity ion beams, which make it possible to measure extremely small cross sections and study rare...
The European Spallation Source (ESS) is a multi-disciplinary neutron research facility currently under construction in Lund, Sweden. Its driver is a multi-megawatt proton linear accelerator that pushes the boundaries of technology and physics for high-power, high-intensity, low-loss operation. Once completed, the linac will accelerate a 62.5 mA, 2.86 ms, 14 Hz proton beam up to 2 GeV through a...
Since starting scientific user operation in May 2022, the driver linac in The Facility for Rare Isotope Beams (FRIB) at Michigan State University has provided more than a dozen ion beam species from Oxygen to Uranium to the production target. FRIB has routinely provided 20 kW primary beams on target since March 2025, which is a factor of 20 higher than at the beginning of scientific user...
To ensure the reliable operation of The China Initiative Accelerator Driven System (CiADS), the stringent real-time failure compensation of superconducting cavities in linac is crucial. We have developed a reinforcement learning algorithm based on segmented compensation strategy, which can achieve fast, adaptive optimization and almost instantaneous compensation scheme acquisition across...
The International Muon Collider Collaboration (IMCC) was established following the 2020 Update of the European Strategy for Particle Physics, with the aim of assessing the feasibility of a muon collider operating at a centre-of-mass energy of ~10 TeV. The concept of colliding beams of oppositely charged muons dates back to the late 1960s, with foundational work by F.F. Tikhonin, G.I. Budker,...
In the J-PARC accelerators (400-MeV H- linac, 3-GeV RCS and 30-GeV MR), two projects to increase beam power to more than 1 MW are now in progress. Linac and RCS achieved a 1-MW design beam power for MLF in 2024 with extremely low beam loss. This successful achievement opened a door to further beam power ramp-up beyond 1 MW. The next beam power target for MLF is now set at 1.5 MW, and both beam...
CSNS (China Spallation Neutron Source) is an accelerator-based facility that generates high-intensity short-pulse neutrons for multidisciplinary research platforms. Its accelerator system includes an 80 MeV H⁻linac and a 1.6 GeV rapid-cycling synchrotron, with a designed target power of 100 kW. The facility has operated stably for 7 years and yielded a number of research achievements. CSNS...
High-intensity hadron machines stand at the forefront of applied and fundamental research. Pulsed spallation neutron sources harness intense proton beams to drive advances in fields ranging from quantum materials to cultural heritage. Meanwhile, high-energy particle physics colliders are revolutionizing our understanding of the universe's structure. The performance of these accelerators has...
HIAF project is a major national science and technology infrastructure project in China which aims at providing high intensity ion bunches at the repetition frequency of 3 Hz for scientific research or industry applications from international users. In the complicated manipulations that generate those high intensity beams, diverse high intensity effects, especially space charge effects,...
This contribution reviews high-intensity and high-brightness effects through the CERN accelerator complex, from the H- and heavier ions' sources/linacs to the injector synchrotrons and the Large Hadron Collider (LHC), for several beam flavours and physics users. It covers various beam dynamics limitations and mitigations applied in order to reach high beam performance while maintaining low...
Charge stripping is a highly beneficial technique in a heavy ion accelerator to improve acceleration efficiency. However, the beam after the stripping is distributed over several charge states, which leads to low stripping efficiency.
The driver linac of the Facility for Rare Isotope Beams (FRIB) at Michigan State University is designed to simultaneously accelerate multi-charge states of a...
A detailed study on random resonances was conducted to facilitate further beam power ramp-up in the 3-GeV rapid cycling synchrotron of the Japan Proton Accelerator Research Complex. Systematic experiments employing a low-intensity beam revealed considerable excitation of the 2nd-order random resonances, namely horizontal half-integer and linear sum resonances, located just above the current...
The RAON linear accelerator consists of a front-end injector and a superconducting linear accelerator (SCL3). The injector includes a 14.5 GHz Electron Cyclotron Resonance (ECR) ion source and a Radio Frequency Quadrupole (RFQ). The ECR ion source can generate a wide range of ion beams, from protons to uranium, with an energy of 10 keV/u. The RFQ accelerates these ion beams up to 500 keV/u....
In the intensity-frontier proton synchrotron J-PARC Main Ring (MR), a power upgrade plan is underway to achieve 1.3 MW beam power for neutrino experiments. The upgrade has generally progressed as planned, with the beam power for the user operation reaching 830 kW as of May 2025. A major obstacle to upgrading the beam power of the MR is the radioactivation of accelerator components caused by...
We present, in this paper, the design result of the beam dynamics for a heavy-ion injection line of the Xi’an 200 MeV Proton Application Facility (XiPAF) upgrading project. The heavy-ion injection line consists of an electron cyclotron resonance (ECR) ion source (IS) system, a low energy beam transport line (LEBT), a four-vane radio frequency quadrupole (RFQ) accelerator, an interdigital...
Advanced Virtual Accelerator Software is a high-performance simulation tool for modeling beam transport processes in high-intensity linear accelerators. AVAS has multiple functions, including multi-particle tracking, engineering analysis, multi-beam transport, and preset accelerator operational parameters. Algorithmically, the Particle-in-Cell algorithm has been modified based on symmetry...
High Intensity Heavy-ion Accelerator Facility (HIAF) is a giant accelerator facility aiming at high intensity primary and secondary beam preparation which is under construction in China. To achieve the challenging intensity goal, high intensity beam preparation remains a top priority of dynamics research. The first issue is how to accumulate in BRing with High injection gain(>56) and low beam...
The SIS100 synchrotron and its booster SIS18 synchrotron will produce high-intensity heavy-ion beams at the space-charge limit. The transverse collective instabilities can endanger the safe operation, the single-bunch and the coupled-bunch instabilities with non-rigid oscillations are anticipated. As the major means for the instability suppression, the octupole magnets for Landau damping will...
In high-intensity ion accelerators where beam density is high and beam velocity is low, the beam receives a significant impulse from the self field. This results in a sudden emittance growth over a short distance. This emittance growth manifests at the local level, necessitating the employment of analytical and suppression methods that differ from conventional approaches. Conventional methods...
This paper reviews various activities regarding primary particle production for the entire CERN accelerator complex,the Linac3 lead ion and Linac4 H- operation and studies possible future upgrades and consolidation of the injectors. Besides lead ions, Linac3 provides a variety of different ions for the LHC and fixed target experiments. The Linac4 H- source was recently improved with a new...
Construction of the NICA collider is approaching to its end with the beam circulation in the collider rings expected by the beginning of 2026. Successful collider commissioning requires obtaining high intensity heavy ion beams in its injector string. The talk discusses up-grades of the injection complex aimed at radical increase of the injection complex intensity. In general, there are two...
The European Spallation Source in Lund, Sweden, is a facility under the final stages of its commissioning process, with the first user program planned in 2027. The 600 m long proton linac underwent beam commissioning in Spring 2025 with first beams through the superconducting part of the accelerator and to the tuning beam dump. This last commissioning run aimed to test all the critical linac...
The tuning and stabilization of long normal conducting radiofrequency cavities present specific challenges that are critical for the reliable operation of linear accelerators. When the cavity length exceeds the RF wavelength several times, small mechanical deformations, misallignement and thermal gradients can lead to significant detuning, acceleting field distortion and excitation of unwanted...
For the China Spallation Neutron Source (CSNS), the rapid cycling synchrotron (RCS) accumulates and accelerates the injection beam to the design energy of 1.6 GeV and then extracts the high energy beam to the target. The CSNS design beam power is 100 kW, with the capability to upgrade to 500 kW. By February 2020, the beam power had reached 100 kW, and through improvements, the beam power was...
The European Spallation Source (ESS) has recently completed beam commissioning up to the tuning beam dump, reaching a proton energy of 800 MeV. This talk will focus on the technical commissioning of the linear accelerator, covering both the normal-conducting and superconducting sections, as well as the testing and integration of superconducting cryomodules. We will describe the phased...
The QWR/HWR/Elliptical cavity cryomodules have been developed for proton and heavy-ion linacs at the Institute of Modern Physics (IMP) of the Chinese Academy of Science (CAS). In this paper, the development situation of the cryomodules for IMP has been reported. The application of some specific design effectively improves the commissioning performance of the cryomodule. These cryomodules are...
The Japan Proton Accelerator Research Complex (J-PARC) linac has been operated with a design peak current of 50 mA since 2018, and several test operations have been performed at a higher peak current of 60 mA. Furthermore, an even higher beam current is being investigated for future projects at J-PARC. To achieve such high beam currents, it is essential to understand beam dynamics and minimize...
The Facility for Rare Isotope Beams (FRIB) at Michigan State University is a heavy ion accelerator facility for nuclear science. Since starting scientific user operations in May 2022, the beam power of the driver linac has been gradually increased to 20 kW. A dozen of ion beams from Oxygen to Uranium has been routinely provided to the production target. In this presentation, the systems...
The Korea Multipurpose Accelerator Complex (KOMAC) has been operating a 100 MeV Proton Linear Accelerator (Linac) since 2013, supporting various research and industrial applications by providing proton beams to users through four regularly used beam lines. In addition to these, a neutron beam line has completed pilot operations and is set to begin user services. In parallel, maintenance and...
The CERN Proton Synchrotron Booster (PSB) produces a wide variety of high intensity and high brightness beams for the fixed target experiments and the Large Hadron Collider (LHC). As part of the LHC Injectors Upgrade (LIU) project, many upgrades were made to the accelerator, including a new injector, Linac4, increased injection and extraction energies, charge exchange injection and new RF...
The project Anthem, funded within the Next Generation EU initiatives, includes the realization of an accelerator based BNCT (Boron Neutron Capture Therapy) facility at Caserta, Italy.
The INFN (LNL, Pavia, Napoli, Torino) has in charge the design and construction of the epithermal neutron source, that will assure a flux of 10^9 n/(s cm2) with characteristics suited for deep tumors treatment....
The IFMIF-DONES facility will irradiate and characterize materials to be used in fusion reactors using a neutron flux produced by the interaction of a deuteron beam with a liquid lithium target. A superconducting radiofrequency linear accelerator will bring the deuteron beam to the final energy of 40 MeV through a series of superconducting half-wave resonators operating at 175 MHz. A prototype...
Enhancing the accelerating gradient and intrinsic quality factor (Q₀) of SRF cavities is critical for next-generation accelerators. This work reports two advances from IMP: (1) Thermal Management with AlN Coatings: To address thermal limitations, this study demonstrates enhanced thermal diffusivity in SRF cavities via inner-wall aluminum nitride (AlN) coatings. Innovative thermal conductivity...
The China Spallation Neutron Source (CSNS) successfully achieved its design power level of 170 kW in 2025. The CSNS-II project aims to increase the beam power to 500 kW by enhancing the linac energy to 300 MeV. To ensure coordinated operation across all accelerator subsystems amidst increasing complexity and precision requirements, the timing system has been redesigned with an event-driven...
During the commissioning of the ESS LINAC in early summer 2025, we recorded beam-loading transients from a 5 µs, 5 mA beam in 47 superconducting cavities: 26 Spoke and 21 Elliptical Medium Beta. We compare the beam-induced cavity voltage and current phasors with a standard beam-loaded cavity model that includes coupling, loaded $Q$, and detuning, thereby validating model parameters across the...
Transverse feedback suppresses beam instabilities that are prominent in high-intensity beams and is essential for their stable acceleration. At J-PARC, a digital signal processor is being developed for the transverse feedback systems in the Main Ring and RCS proton synchrotrons. The processor uses an RFSoC, an FPGA with integrated ADCs and DACs. It segments 100-ns-long bunches at a sampling...
GANIL (Grand Accélérateur National d’Ions Lourds) started the operation of the SPIRAL2 superconducting linac in 2022. Experiments in the Neutron For Science (NFS) room, specific beam dynamics studies, and various technical improvements are carried out during its operation in the second half of each year, after the run of the cyclotrons in the first half. In 2024, a first period of parallel...
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The international Facility for Antiproton and Ion Research (FAIR) is being built at the GSI Helmholtz Centre in Darmstadt. The first project stage includes the superconducting 100 Tm heavy ion synchrotron SIS100, the Super Fragment Separator, and associated beam transport lines. The GSI's ion sources, UNILAC and SIS18 will provide the beams. Installation work in the FAIR accelerator tunnels...
Optical imaging systems have been designed and installed upstream of the European Spallation Source (ESS) Tuning Dump (TD) and the ESS spallation Target to provide machine protection and beam tuning support functionalities. The ESS accelerator delivers a high-power, low-emittance proton beam, which must always be controlled. In the TD, the optical imaging systems remotely view the beam profile...
The Heavy Ion Research Facility at Lanzhou (HIRFL) is a significant infrastructure for nuclear physics, atomic physics and application sciences in China. It consists of linac injector, cyclotrons, synchrotrons and several experimental terminals. Heavy ion beams up to uranium can be accumulated, accelerated and delivered to different terminals. Recently, a CW linac was installed as the injector...
Electron beam injectors, critical to light sources and ultrafast diffraction systems, need precise transverse phase space diagnostics for optimizing beam quality. The slit-scanning method, often combined with computed tomography (CT), is common for non-presumptive phase space reconstruction but has resolution limits due to sparse sampling and constraints of devices/experimental conditions.This...
The Linear IFMIF Prototype Accelerator (LIPAc) aims to demonstrate CW acceleration of a 125 mA deuteron beam up to 9 MeV using an RFQ and SRF linac. Before SRF linac installation, the beam commissioning was conducted with a 5 MeV deuteron beam. Attempts to increase the duty cycle revealed a significant pressure rise detected by sensors, presumably caused by beam halo, which had previously...
The European Spallation Source (ESS) is a neutron research facility based in Lund, Sweden. Its linear accelerator will operate with a high peak current of 62.5 mA and a long pulse length of 2.86 ms at a repetition rate of 14 Hz, enabling it to deliver 2 MW of beam power to the target. In the first half of 2025, accelerator commissioning was completed with the achievement of a beam energy...
The Fast Protection System (FPS) is critical for ensuring the efficient and safe operation of the large-scale scientific facility at the China Spallation Neutron Source (CSNS). To address the enhanced requirements of CSNS-II, an advanced FPS architecture has been developed, leveraging high-performance field-programmable gate arrays (FPGAs), high-speed rocket IO serial communication links, and...
Quantifying differences between high-dimensional phase space distributions is essential for analyzing beam measurements and simulations. While f-divergences such as KL or JS divergence are increasingly used for this purpose, including in machine learning applications, their values lack physical interpretability. This work establishes the first physics-grounded framework for f-divergences in...
The J-PARC Main Ring is a 30 GeV proton synchrotron with two extraction modes: fast and slow. The slow extraction is performed using the third-order resonance of betatron oscillations, and the extracted beam is delivered to a variety of particle and nuclear physics experiments at the Hadron Experimental Facility. An upgrade of the Main Ring carried out from 2022 to 2023 significantly shortened...
Fast and precise beam dynamics simulations are essential for particle accelerator design and optimization. Machine learning enables fast end-to-end surrogate models, but these often fail in beamline parameter optimization. We propose a physics-constrained temporal convolutional network (TCN) to predict Twiss parameters along the beamline. The model achieves high-precision 6D to 350×6D mapping,...
An optimization toolkit named VeRDe (Venetian RFQ Design) has been developed at the Legnaro National Laboratories for the design of Radiofrequency Quadrupoles (RFQs). It builds on well-established RFQ design methodologies and is based on the Los Alamos codes: PARMTEQM, PARI, RFQuick, and CURLI. The toolkit enables detailed control over the evolution of key RFQ cell parameters, like voltage...
The proton complex is the first piece in the Muon Collider, it comprises a high power acceleration section, a compressor and a target delivery system. For the International Muon Collider Collaboration (IMCC) we are investigating two possibilities: a 5 GeV (2 MW) and a 10 GeV (4 MW) final energies. In this work we present the updated design for the proton complex, including chopping schemes for...
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The High Intensity Heavy-ion Accelerator Facility (HIAF) will be one of the world’s leading heavy-ion accelerators in the near future that enables to explore the unknown territories in nuclear chart, atomic physics research in experiments and heavy-ion applications. This facility is composed of a fully superconducting linear accelerator iLINAC, a fast-cycling synchrotron BRing, and six...
Since 2013, the Korea Multi-purpose Accelerator Complex (KOMAC) has been operating a 100 MeV linear proton accelerator. Designed from its inception with the long-term vision of upgrading to a high-power spallation neutron source, KOMAC's proton accelerator aims to achieve a final energy of 1 GeV. As an intermediate milestone toward this goal, a 200 MeV energy upgrade is currently being...
Space charge effects are the main performance limitation for the beam brightness in the CERN Proton Synchrotron Booster (PSB). Operating at higher vertical tunes, near or above the vertical half-integer resonance 2Qy=9, offers more space in the tune diagram to accommodate the large space charge tune spread, potentially allowing for brighter beams. In this context, an experimental campaign was...
Commissioning of the China Spallation Neutron Source (CSNS) began in 2018, achieving a neutron production beam power of 100 kW. An upgrade program CSNS-II launched in 2024 aims to reach 500 kW within the next few years. Throughout these developments, several multidisciplinary application facilities have been deployed or are planned for deployment: Associated Proton Beam Experiment Platform,...
The China Spallation Neutron Source (CSNS) utilizes ceramic vacuum chambers in the high-dynamic-field regions of the Rapid Cycling Synchrotron (RCS) to preserve the vacuum environment of beam. Previous theoretical studies suggested that the impedance of this structure could be neglected concerning its impact on the beam. Recent measurements, however, have detected low-frequency resonant...
The High Brilliance Neutron Source (HBS) is a new High Current Accelerator-driven Neutron Source (HiCANS) project, planned and to be realized at the Forschungszentrum Jülich, Germany.
The project represents a promising alternative for expanding neutron availability in Europe by using a high-current, low-energy proton accelerator and state-of-the-art technologies to deliver thermal neutron...
ISIS is the pulsed muon and neutron source at RAL in the UK. Its operation centres on an 800 MeV rapid cycling synchrotron (RCS) running at 50 Hz, delivering 3×10¹³ protons per pulse and 0.2 MW average beam power to neutron targets.
Current studies are aiming to improve the measurement, modelling, and control of ISIS ring beam dynamics, with the goal of optimizing operational setup and...
Based on the operational experience on the superconducting heavy ion linac ALPI, we introduced Machine Learning techniques to improve the performances and speed up the tuning of the ion linac at LNL.
The technique proved to be particularly effective to overcome issues on the longitudinal matching.
The algorithm has been adapted to be compatible with high intensity linacs, in terms of...
The ISIS rapid-cycling synchrotron accelerates a high-intensity
beam of protons from 70 MeV to 800 MeV at 50 Hz,
facilitated by ferrite-loaded RF cavities at harmonics ℎ = 2
and ℎ = 4. The extracted proton beam is delivered along
separate transfer lines to two tungsten spallation neutron targets,
TS1 and TS2, at rates of 40 Hz and 10 Hz respectively.
An intermediate carbon target on the...
The IFMIF-DONES facility aims to generate a high flux of 14 MeV neutrons (up to 10$^{18}$ n m$^{-2}$ s$^{-1}$) to enable the characterization and qualification of materials for future fusion reactors. To accomplish this, it will use a continuous-wave (CW) linear accelerator delivering a 125 mA deuteron beam at 40 MeV onto a liquid lithium target. This configuration presents a unique challenge,...
Beam coupling impedance is a fundamental performance limitation in high-intensity hadron rings, affecting both beam stability and the thermal load on accelerator components. As beam intensity increases, impedance-driven collective effects—such as transverse mode coupling and longitudinal coupled-bunch instabilities—become more pronounced, while beam-induced power losses can cause local...
High-intensity multi-bunch beams in the CERN Super Proton Synchrotron (SPS) experience significant coherent and incoherent tune shifts due to the transverse beam coupling impedance. Studies with LHC-type beams have been performed to optimize the working point along the extended SPS injection plateau to enhance beam performance and brightness. The initial tune correction approach focused on...
An RF-driven $\mathrm{H^-}$ ion source has been developed and put into commissioning at the China Spallation Neutron Source (CSNS). The ion source features a silicon-nitride plasma chamber and an external antenna structure. It has demonstrated a maintenance interval exceeding 7,500 hours with nearly 100% availability.To achieve the goal of delivering a 500 kW beam power to the spallation...
The main ring synchrotron (MR) of Japan Proton Accelerator Research Complex (J-PARC) provides high power proton beams for the neutrino and hadron experiments with fast extraction (FX) and slow extraction (SX), respectively. We have achieved FX 830 kW continuous operation and demonstrated FX 955 kW equivalent beams. We are aiming at FX 1.3 MW operation by 2028. In this talk, we will present the...
CEA Paris-Saclay has been engaged in the development of high-intensity proton sources since the early 1990s, beginning with the SILHI ECR ion source, designed to inject beam into the IPHI accelerator. Still in operation today, SILHI has demonstrated long-term stability and reliability. To improve compactness and ease of maintenance, a redesign of the plasma chamber was initiated. This effort...
The Engineering Validation and Engineering Design Activities for the International Fusion Materials Irradiation Facility (IFMIF/EVEDA) are being conducted under the Broader Approach agreement between EURATOM and the Japanese government. The Linear IFMIF Prototype Accelerator (LIPAc) aims at validating the design of the low-energy section of the 40-MeV/125-mA IFMIF deuteron accelerator, thus up...
The China Spallation Neutron Source (CSNS) accelerator complex comprises an 80 MeV H⁻ normal-conducting linear accelerator (linac), a 1.6 GeV rapid cycling synchrotron (RCS), and associated beam transport lines. Following multiple rounds of beam commissioning, the beam power delivered to the target has been successfully increased to 170 kW, surpassing the design value by 70%. Building on this...
During the long-term shutdown in FY2021, major upgrades of the main magnet system in the J-PARC Main Ring (MR) were carried out, including the installation of new power supplies, rearrangement of existing PSs, restructuring of magnet families, and cable re-wiring, contributing the beam extraction repetition period for the T2K experiment shortened from 2.48 s to 1.36 s, enabling operation at...
The Linac4 H⁻ ion source plays a vital role for the CERN operation and experimental users. Its performance and availability have a direct and critical impact on the CERN's proton accelerator chain and the physics programs it supports. This paper presents an overview of the system, the operational experience and the lessons learned during the full five years of official running. Key topics as...
The ISIS Rapid Cycling Synchrotron (RCS) operates at a repetition rate of 50 Hz and delivers high-intensity proton beams of up to $3\times10^{13}$ protons per pulse at 800 MeV to two neutron and one muon production targets. Maintaining control over the closed orbit is essential to optimal performance. Magnet alignment surveys are now regularly carried out during accelerator shutdowns,...
The world's first Nb3Sn and NbTi superconducting electron cyclotron resonance (ECR) ion source, FCER (First 4th-generation ECR ion source), has been deployed in the LEAF (Low Energy high-intensity heavy ion Accelerator Facility) project in 2024. Following initial tuning, under 28+45 GHz microwave heating, the FCER successfully produced 350 eμA of Bi35+ and 620 eμA of Bi31+ ion beams. Recently,...
The China Spallation Neutron Source (CSNS) is a major facility for neutron science in China, and is currently operating at an averaged beam power of 170 kW with a beam energy of 1.6 GeV and repetation rate of 25 Hz. In 2024, the CSNS Upgrade project (CSNS-II) was launched aiming to improve the average beam power to 500 kW. In the sequence, a number of new instrumentations will be equiped at...
With the application of in (RCS) of China Spallation Neutron Source(CSNS), space charge effect has been mitigated effectively, the beam power is reaching 170kW with stable operation. However, under high beam power conditions, the strong beam loading effect becomes the primary challenge for the second harmonic RF system. In order to keep system run steadily under complex working conditions,...
The collimation system of the Large Hadron Collider (LHC) at CERN represents the state of the arc of multi-stage collimation systems. It provides an excellent cleaning performance that has so far ensured safe and efficient operation of the LHC with beam stored energies up to 430 MJ. However, further improvements are needed in view of the High-Luminosity upgrade of the LHC (HL-LHC) that will...
Detailed knowledge of high-dimensional phase space distributions is crucial for predicting and controlling the evolution of intense beams. Conventional beam tomography techniques require measurements under multiple beamline configurations, introducing reconstruction errors due to transport nonlinearities and model uncertainties while complicating the beamline design. This paper introduces SOFT...
ISIS is the pulsed, spallation neutron and muon source at the Rutherford Appleton Laboratory in the UK. Its rapid cycling synchrotron accelerates 3e13 protons-per-pulse from 70 to 800 MeV at 50 Hz, delivering a mean beam power of 0.2 MW to its two target stations. The intensity of ISIS is beam-loss limited, so increasing its neutron and muon output requires beam-loss mechanisms to be well...
The European Spallation Source (ESS) in Lund, Sweden, is a pulsed neutron source based on a proton linac. The ESS linac is designed to deliver a 2 GeV beam with a peak current of 62.5 mA at 14 Hz to a rotating tungsten target for neutron production.
One of the most critical elements for protection of the accelerator is a beam loss monitoring (BLM) system. The system is designed to protect the...
For the high power spallation neutron sources, the laser-assisted H− stripping is a new essential technology. It can be an alternative to the foil stripping which may be used to overcome various difficulties faced by the stripping foils, such as short lifetime, high temperature, large radiation dose, etc. In this paper, based on the phase II of China Spallation Neutron Source (CSNS-II), the...
High-intensity hadron machines host beams with destructive power, and traditional beam profile monitors, such as scintillating screens and wire scanners, suffer a short lifetime under such severe conditions. The application of the beam gas curtain monitor (BGC) in the LHC, along with 2 years of successful operation, fills the gap in such measurements in a minimally invasive manner for...
We present PyFFA, a Python-based simulation framework developed for high-intensity beam dynamics studies in circular accelerators with unfixed closed orbits. The code features multi-particle tracking with self-consistent 2.5D Particle-In-Cell (PIC) space charge calculations and supports multi-turn painting injection for long bunches in accelerators such as FFA machines and cyclotrons.
The High-Luminosity upgrade of the Large Hadron Collider targets a yearly integrated luminosity of $300\,\text{fb}^{-1}$. Following several hardware upgrades, the bunch intensity is foreseen to be raised to $2.2 \cdot 10^{11}$ protons per bunch. The resulting beam loading poses a challenge for the main radio frequency (RF) system of the LHC. The limited RF capture voltage and an enlarged...
Coupled-bunch instabilities will occur with long-range wakefields. And it’s an effective way to adjust the chromaticity to suppress transverse coupled-bunch instabilities. There are some theoretical studies showing that strong space charge can weaken the suppression effect of chromaticity. In this paper, transverse coupled-bunch instabilities with space charge are simulated and analysed using...
The CERN Proton Synchrotron Booster (PSB) operates at two nominal extraction energies, 1.4 GeV and 2 GeV, each presenting distinct achievable beam intensities. To mitigate longitudinal instabilities, the PSB RF system employs a combination of double-harmonic voltage and multi-harmonic cavity feedback loops. When operating with single-harmonic voltage and open cavity loops, a fast instability...
The challenge of delivering FLASH irradiation to large volume targets within 100 ms using 3D pencil beam scanning (PBS) persists. A novel scanning scheme based on a rapid-cycling synchrotron (RCS) is proposed. This work introduces a longitudinal localized kick driven fast extraction method used in the scheme. By applying stripline kicker pulses to specific longitudinal segments of the bunch...
Controlling induced radioactivity remains crucial for high-intensity proton accelerators. This study analyzes radiation hotspots in a Rapid Cycling Synchrotron (RCS) using extensive dose measurements (2018-2025). We identified hotspots (>5 mSv/h) exhibiting either transient ("peaking-then-decreasing") or persistent ("increasing-then-stabilizing") behavior. Strategic measures - orbit...
CSNS-II superconducting Section Beam Loss Measurement Electronic Design
The CSNS-II linear accelerator upgrade will adopt superconducting accelerator structures, with the beamline enclosed in low-temperature modules. Detection of beam loss can only be done on the outer surface of the low-temperature modules. The CSNS-II accelerator plans to use a parallel plate multi-electrode ionization...
This study explores the use of Bayesian optimization in reducing CSNS RCS beam loss. Bayesian optimization is a global optimization framework ideal for complex, black-box functions. By building a probabilistic model of the objective function, often a Gaussian process, it selects new sampling points based on predicted uncertainty, efficiently finding the optimum with limited resources. It has...
Longitudinal ion beam stacking in a storage ring using a barrier rf system combined with beam cooling has been successfully demonstrated in several experiments. Based on the bunching effect observed in the pulsed electron beam cooling experiment at HIRFL-CSRm, we propose a new beam stacking scheme using only pulsed electron beam, in which the barrier voltage and cooling process can be achieved...
We propose an end-to-end deep learning method for reconstruction of proton synchrotron longitudinal phase space distributions from 1D beam current projections. Unlike iterative tomographic approaches, our model bypasses complex physics computations by establishing a direct sequence-to-image mapping. The architecture integrates sinusoidal positional encoding to capture multi-turn temporal...
This paper presents an overview of the beam intensity measurement system for the C-band photocathode electron gun platform, detailing the observed phenomena during measurements and the associated experimental investigations. The system’s design, operational principles, and key components are introduced, followed by an analysis of critical measurement results and unexpected behaviors, such as...
At the J-PARC Main Ring, a project is in progress to upgrade the beam power to 1.3 MW for the neutrino oscillation experiment. Control of the optics and beam orbit relative to the magnetic center of the accelerator components is crucial to suppress beam losses in intense beams. We need to reduce the determination error of the beta function from the current value of 2% to less than 1%....
Neutron energy spectrum measurement imposes requirements for single-bunch selection and acceleration on the CiADS (China Initiative Accelerator Driven System) superconducting linear accelerator, which operates at a fundamental frequency of 162.5 MHz. Existing chopper power supplies have rise/fall times approaching 20 ns, making them unable to achieve the required 6.15ns bunch selection via a...
The rational use of multipole magnets in a beam line is an effective method of transverse beam profile uniformization. This paper introduces an octupole magnet uniformization design of an about 2.1 MeV proton beam accelerated by a RFQ accelerator and the design is based on TraceWin. This design contains two octupole magnets, which are dedicated to uniformization of x and y directions...
Ultra-high dose rate (FLASH) radiotherapy is emerging as a novel cancer treatment due to its tumor-killing efficacy and superior normal tissue protection compared to conventional therapy. However, in compact synchrotrons, achieving the required FLASH dose rates is challenging, since conventional RF-KO extraction struggles to achieve the short (tens of milliseconds) extraction times needed. To...
The integration of machine learning (ML) techniques into beam commissioning and operations at CSNS has shown promising potential for improving beam quality, operational efficiency. This work presents a comprehensive overview of recent ML applications across multiple stages of CSNS operations. A key foundation of these efforts is the development of an AI-ready dataset generation platform, which...
Longer bunch spacing is essential for precise product detection in certain nuclear physics experiments. At LEAF, a 10.156 MHz pre-buncher has been successfully commissioned, producing a 98.4 ns main-bunch spacing with a measured FWHM of 1.7 ns using a fast Faraday cup. Residual satellite bunches at the 12.3 ns linac micro-pulse period necessitate a dedicated RF deflector to remove unwanted...
To enable the compact design of an accelerator-driven neutron source, this study developed a beamline scheme that combines a double Einzel-lens focusing system with a compact RFQ accelerator. A double Einzel-lens configuration is employed in the low-energy beam transport section, successfully reducing its length to less than 0.2 m. The accelerator section utilizes a 325 MHz four-vane Radio...
A superconducting radio-frequency quadrupole (SRFQ) is proposed for the future upgrade of the China Initiative Accelerator Driven System (CiADS). The SRFQ is de-signed to accelerate a 10 mA proton beam to 2.5 MeV within a compact length of 2.9 m. This design achieves 100% transmission efficiency and a carefully controlled output longitudinal emittance, ensuring minimal beam loss in the...
Beam loss is a critical challenge in the physics design of high power superconducting proton linacs. The challenge is even more acute in linacs that feature high peak intensity and low energy, which has strong space charge effect and RF nonlinear force. In this paper, we study how to achieve a high transmission rate for beam halo particles, commonly a major source of beam loss, via beam halo...
To make ion accelerators in applications more compact, the Institute of Modern Physics, Chinese Academy of Sciences is dedicated to researching the radio frequency quadrupole (RFQ) operating at a frequency as high as 1 GHz. While high frequency can effectively enhance the acceleration gradient of RFQ, it also leads to low transverse focusing force, reduced acceptance and decreased transmission...
Beam loss is the most critical topic in the high power accelerator community. During high power proton beam commissioning of Chinese ADS Front end (CAFe), unexpected irradiation dose was detected opposite to the proton beam deflection direction. This indicates there are parasitic negative hydrogen particles inside the proton beam, which is first observed in the linac facility. In the paper,...
In the 3-GeV RCS of J-PARC, we have already achieved user operation at the designed 1 MW beam power. The beam loss and the corresponding machine activation have been sufficiently minimized to obtain a stable operation. To cope with user demands, the beam power of the RCS has to be increased far beyond the designed 1 MW. For that purpose, we have performed numerical simulation and beam studies...
Laser-driven proton sources produce ultra-short, high-current pulses ideal for FLASH radiotherapy but lack therapeutic energy levels. Bridging this energy gap via RF linac post-acceleration faces critical beam transport challenges due to wide angular divergence and broad energy spreads intrinsic to laser protons. This work analyzes how large energy spreads constrain RF bunching and capture...
Accurate setting and readback of radio frequency (RF) cavity voltage is critical for precise beam control in accelerator systems. To address potential discrepancies between set and actual voltages, this study presents an in-situ calibration of the MEBT Buncher1 cavity using a Time-of-Flight (ToF) method. The phase of the cavity was systematically swept while measuring the resulting energy...
A residual gas Ionization Profile Monitor (IPM) was designed and installed in CSNS-Linac for horizontal beam profile measurement. In the design of the IPM, the use of equipotential electrodes was abandoned. Instead, a honeycomb structure is incorporated at the openings of the anode plate to suppress the horizontal component of the electric field. The shadowing introduced by the honeycomb...
Resonance crossing, jointly determined by a large space-charge tune spread and magnetic field errors, is the main cause of beam loss and emittance growth in HIAF-BRing. For weak beams, the classical theory based on the resonance driving terms (RDTs) allows a perfect resonance compensation through precisely pre-known nominal TWISS parameters. As the space-charge gets intensified, however, the...
CiADS (China initiative Accelerator Driven sub-critical System) is an experiment facility to demonstrate the ADS concept with high energy proton beam hitting the LBE (Liquid Lead-bismuth Eutectic) target, generating high-flux neutrons to boost the reacotor to transmutate nuclear waste. BLR (Beam Line to Reactor) is one of the key part in CiADS program, which is to transport and match the 2.5...
The CSNS RCS (Rapid Cycling Synchrotron) is a proton accelerator designed to achieve a target beam energy of 1.6 GeV, with a typical operating intensity of 140 kW, which is expected to increase to 500 kW after the CSNS II upgrade. However, a significant current instability has been observed during the 100 kW beam operation. To mitigate this instability, techniques such as operational tuning...
The muon collider is a promising candidate for exploring new physics at the energy frontier, offering the advantages of lepton collisions at multi-TeV scales. Achieving high luminosity requires reducing the six-dimensional (6D) emittance of the muon beam by several orders of magnitude within the muons’ limited lifetime. This is accomplished through ionization cooling, which involves two main...
For multi-unit RF amplifier systems, a 2300 W solid-state RF power amplifier module with integrated EtherCAT and USB interface has been developed. The RF amplifier section is constructed from the latest LDMOS from Ampleon with a power of 2300 W at an efficiency of 72 % and is fully shielded and offers space for adding a driver amplifier or phase shifter circuit. The module is equipped with a...
After the success of 80 MeV negative hydrogen beam profile measurement based on laser wire monitor, in order to further realize the beam emissivity measurement, an emissivity measurement system combining the laser wire monitor and LGAD (low-Gain Avalanche Diode) sensor is designed in this paper. The main idea is to use the LGAD sensor to reconstruct the H0 distribution, combined with the laser...
The upgrade of linac in China Spallation Neutron Source (CSNS-II) requires a robust Differential Beam Current Measurement (DBCM) system to ensure safe operation of superconducting cavities within the Fast Protection System (FPS). This paper presents a practical design for a DBCM system tailored for the chopped-beam operation. The system integrates a Bergoz Fast Current Transformer (FCT) with a...
The Beam Loss Monitor (BLM) system for the High-Intensity heavy-ion Accelerator Facility (HIAF) has been constructed and deployed. This system features ultra-fast response (≤20 μs, measured down to 4.5 μs) and employs 196 plastic scintillator detectors coupled to photomultiplier tubes (PMTs), strategically positioned in critical areas. It achieves a wide dynamic range of 6 orders of magnitude,...
At the ISIS Neutron and Muon Source, accelerator tuning has traditionally been a manual process, relying on expert operators to adjust control system parameters to achieve optimal beam efficiency and intensity. With the recent migration of the control system to EPICS and the availability of optimization frameworks such as Xopt, we have initiated the first efforts to automate tuning of the Low...
Target Multi-Wire Scanner is a beam diagnostics device in the CSNS-II accelerator, designed to measure the pre-target beam profile. This paper details the hardware composition, software architecture, and beam-target interaction test results of the CSNS-II front-end multi-wire scanner readout system. In contrast to the CSNS predecessor, the upgraded system employs a hybrid software architecture...
Dynamic aperture tracking is an widely employed and effective method in the design of circular accelerators. However, in high-intensity proton accelerators, the pronounced space charge effect induces substantial tune shifts, which can severely compromise the accuracy of nonlinear dynamics analysis. In this study, we present a novel dynamic aperture tracking code tailored for high-intensity...
In the case of “linear RF system” the longitudinal Schottky noise of bunched beam is presented as a set of synchrotron lines around each revolution harmonics or, in the case of transverse Schottky noise, around each betatron sideband. In a typical accelerator or storage ring the RF system generates harmonic RF which makes the synchrotron motion non-linear resulting in a dependence of...
Beam tuning in particle accelerators is a complex task, especially when physical modeling is impractical due to the lack of complete beam diagnostics. Manual, iterative adjustment by operators is time-consuming and often fails to converge rapidly on optimal settings.
We propose a reinforcement learning (RL) approach accelerated by a surrogate model trained on limited online data, enabling...
The intra-beam scattering in high charge state intense heavy ion beams is a problem worth considering. By controlling the longitudinal distribution of the ion beam, it may be possible to alleviate the ion beam loss and improve the lifetime of the ion beam caused by intra-beam scattering. Unlike the traditional cooling process of direct current electron beams or longitudinal uniform...
For high-intensity hadron synchrotrons, the longitudinal manipulation (rf gymnastic) is of practical importance to customize the parameters and status of the hadron beams to fulfill various scientific and industrial goals. For the recently-built China Spallation Neutron Source (CSNS), a high-intensity single-bunch operation mode based on longitudinal bunch merging has been proposed to enhance...
The China Accelerator Facility for superheavy Elements (CAFE2) stands as a world-leading dedicated facility for superheavy element synthesis research, boasting the highest beam intensity among international counterparts of its kind. It provides advanced experimental conditions for synthesizing new superheavy elements, investigating their chemical properties, and generating neutron-rich...
This paper presents a thermionic cathode electron gun with a compact structure for generating continuous-wave electron beams by introducing 650MHz microwave power into the cathode-grid assembly.
A study campaign to identify potential limitations at highest intensities has been performed in the Proton Synchrotron (PS) in view of future requirements for fixed-target beams at CERN. Previous explorations of the maximum intensity date back more than two decades, and they required two injections from the PS Booster (PSB) with a long flat-bottom in the PS. This scheme resulted in...
HIAF is a high-intensity particle accelerator that will perform injection, acceleration, and extraction at a repetition rate of 3 Hz. The beam will be affected by a variety of high-intensity effects. In order to increase the beam intensity, we hope to fully and accurately simulate the impact of those effects so that we can take appropriate suppression measures. For this purpose, we are...
To mitigate beam loss during RCS injection and in the transport line from the linac to the ring, a novel transverse beam halo collimation system was developed for the CSNS LRBT beamline. The system employs three sets of stripping foils arranged with a 60° phase shift, using twelve carbon foils to convert peripheral H⁻ ions with beam power below 2 kW into protons. Experimental results...
Beam feedback systems are crucial in high-energy circular accelerators to suppress undesired bunch oscillations and prevent beam quality degradation. In the longitudinal plane, the CERN Super Proton Synchrotron (SPS) is equipped with beam phase and synchronization loops. The phase loop locks the RF phase of the accelerating voltage to the one of the bunches detected by a pickup, while the...
The delivery of a high-brightness muon beam through ionisation cooling is essential to produce sufficient luminosity in a muon collider. The ionisation cooling technique has been demonstrated in principle by the Muon Ionisation Cooling Experiment (MICE) but the potential detrimental impacts of collective effects still need to be carefully investigated. Using the same formalism as the one...
To meet the stringent requirements of the downstream superconducting accelerating section for beam matching conditions and intensity specifications, it is necessary to maximize the beam intensity while maintaining the transverse emittance performance at the exit of the normal-conducting front-end. Systematic measurements were conducted of the emittance at the exit of the Low Energy Beam...
Resonant slow extraction is widely utilized in hadron synchrotron accelerators. This paper proposes a longitudinal localized excitation method for slow extraction, in which transverse excitation is applied only within a limited phase interval located at the edge of the longitudinal phase space. As a result, only particles situated in this region are excited and subsequently extracted. This...
Obtaining complete high-dimensional phase space distributions is essential for predicting and controlling intense beam evolution. Building on our prior tomography algorithm that reconstructs four-dimensional (4D) transverse phase space distributions from 2D measurements, applicable under both linear and nonlinear beam transport, this work extends the framework to incorporate frozen space...
Dipole magnet vacuum chambers are among the critical and costly components of rapid-cycling accelerator facilities. Alternative
approaches to traditional ceramic chambers have been explored for the implementation of fast-ramping dipole-magnet vacuum chambers,
including thin-wall metallic beam pipe chambers strengthened with transverse ribs. Here, we report a novel 3D-printed titanium alloy...
ISIS is the pulsed muon and neutron source at RAL in the UK. Its operation centres on an 800 MeV RCS cycling at 50 Hz and providing up to 3E13 protons per pulse corresponding to 0.2 MW mean beam power to the user targets.
Work is presently underway to improve the measurement, modelling, and control of the ISIS ring beam dynamics in order optimise operational setup as well as allow...
In the study of plasma properties of an Electron Cyclotron Resonance Ion Source (ECRIS), it is essential to accurately model the critical features of ECRIS within a numerical framework, particularly for third-generation ECRIS systems that operate at microwave frequencies exceeding 20 GHz. The three-dimensional particle-in-cell model, NAM-ECRIS, has been updated to investigate the response of...
This research presents a new numerical method of the beam envelope equations in the presence of acceleration. By using a scanning technique, a matched solution set with acceleration has been obtained. With focusing cases as constant wave number per unit length, it is found that the conventional adiabatic approximation theory fails when dealing with high acceleration gradients. Moreo-ver, for...
In absence of direct space charge, the indirect electromagnetic self-interaction of particle beams via surrounding materials is typically described by wakefields. Beam stability can then readily be assessed in terms of absolute stability of the dipole moment density using linear stability analysis via eigenfunctions, where small density perturbations either decay (stable regime) or...
Online monitoring of beam phase and energy gain within accelerating cavities is crucial for the stable operation of accelerators, especially in high-power scenarios. As cavities are typically calibrated with a low-current, short-pulse beam for safety purposes, the beam behavior may deviate from the calibrated case when running high-current beams, due to strong space charge effects and other...
The Heavy Ion Research Facility in Lanzhou (HIRFL) is a globally significant full-ion acceleration system. Its Cooler Storage Ring (CSR) facility demonstrates versatile capabilities in beam accumulation, cooling, and acceleration. During operational cycles, periodic beam losses have been observed, prompting an investigation into their root causes.Our study focused on analyzing analog dipole...
As prerequisites for automatic phase setting and fault compensation, precise longitudinal alignment and RF phase calibration are critical for high-intensity superconducting hadron linacs. While multiple facilities have successfully aligned or synchronized their linacs with time-of-flight (TOF) beam-based methods, existing error analyses typically assume uncorrelated position and phase...
Abstract
With the advancement of high-intensity proton linacs, compact neutron sources with a limited footprint have become feasible. Such a neutron source, consisting of a radio frequency (RF) ion source, a radio frequency quadrupole (RFQ), and a rotating Li target, operating in continuous wave (CW) mode, has been proposed. In this paper, we present the overall system design and...
In the China Spallation Neutron Source II (CSNS-II), the H⁻ beam will be accelerated in the Linac to 300 MeV. Subsequently, the electrons are stripped from the H⁻ ions through a stripping foil during injection into the Accumulator Ring, converting them into a proton beam. Wire scanners are employed to measure the transverse beam profile and emittance in the injection area. This paper presents...
High-current or low-energy slow extraction from proton synchrotron suffers from strong space charge effect. Longitudinal localized excitation slow extraction method is proposed in this paper to reduce the spill energy spread while mitigating space charge effects. This method applies transverse excitation within a limited phase interval which locate at the edge of the longitudinal phase...
To enhance the accelerating efficiency of the high-current accelerator for a neutron source, a 100-mA, 162.5-MHz, CW compact hybrid accelerating cavity incorporating inductively coupled four-vane RFQ and CH DTL structures is designed. The dynamics design, the RF structure design, and water-cooling design of the hybrid cavity have been accomplished. The proton beam is accelerated from 80 keV to...
Proton linear accelerators are crucial in spallation neutron sources, CANS, proton therapy, etc. DTL, especially Alvarez-type, is used for intense pulsed proton beams at several to tens of MeV. High-intensity neutron sources characterized by superior temporal resolution, unprecedented peak brightness demand higher pulse current intensity proton linear accelerator. With the in-depth research on...
High reliability is a major challenge of high-current linear accelerators. This is particularly problematic for Accelerator Driven Systems (ADS) such as the China initiative Accelerator Driven System (CiADS). In order to achieve rapid beam recovery, it is necessary to adjust and compensate the superconducting solenoids and cavities adjacent to the failed components in superconducting linear...
High-intensity hadron accelerators demand precise modeling of collective effects to ensure beam quality preservation and beam loss mitigation. RF-Track is a versatile, computationally efficient 6D particle tracking code developed to simulate the dynamics of beams under the influence of space charge, wakefields, and scattering effects in complex accelerator layouts, including RFQs, LEBT and...
The China Spallation Neutron Source (CSNS) is a large multidisciplinary experimental facility that generates neutrons by targeting a strong current proton accelerator. Its linear accelerator consists of a front-end accelerator, a 3 MeV RFQ accelerator, and an 80 MeV DTL accelerator. The second phase of the project will upgrade the linear accelerator by installing superconducting cavities after...
In high-intensity beam transport systems, the interaction between resonance and instability significantly impacts beam quality and transmission efficiency. This study aims to investigate the intrinsic link between resonance excitation and instability growth in mismatched high-intensity beams propagating through periodic focusing channels.
Based on envelope oscillation theory, this paper...
The Rapid Cycling Synchrotron (RCS) of the China Spallation Neutron Source (CSNS) is a key part of the accelerator chain. It accelerates the 80 MeV low-energy beam from the linac to 1.6 GeV and extracts it to hit the target for neutron production. As an important optics parameter, the precise measurement of the transverse emittance is vital for understanding the space charge evolution in the...
In the J-PARC Main Ring (MR), an upgrade project involving a total of 24 Trim-S units is in progress to further suppress beam loss caused by off-momentum particles. This effort targets key resonances, including the third-order resonance 3νx=64 and νx+2νy=64, and a fourth-order resonance 4νx=85, which are produced by the combination of vx=21 and 3vx=64. Four additional Trim-S units have been...
For accumulating high-intensity beam, the H- stripping injection is adopted in the rapid cycling synchrotron (RCS) of the China Spallation Neutron Source (CSNS). For the CSNS-II, the painting injection is a key solution, which is performed in a straight section of RCS by the bump magnets, including four BCH magnets for horizontal painting, four BV magnets for the vertical painting and one LRBD...
Exotic nuclei far away from the valley of β-stability are characterized by tiny production cross-sections and short half-lives, therefore highly efficient and fast mass measurement techniques are required. The Spectrometer Ring (SRing) at the HIAF provides such conditions for accurate mass and unique half-life measurements of exotic nuclei. The SRing is designed as a multi-function...
The slow extraction feedback system is built at HIRFL-CSR, Lanzhou. It is an auto adjusted feedback system based on the predicted value from DCCT at CSRm. The TMIC with the ability of online monitoring spill structure and beam profile is equipped at the terminal. The 10 kHz intensity signal is fed into the electronics of RFKO with a 1 kW power amplifier. The system is operated at July, 2025....
In accelerator-based spallation neutron sources, which include a rapid cycling synchrotron (RCS), the energy spread at the end of the linac is a crucial parameter that significantly impacts the operational efficiency of the downstream RCS ring. However, in recent years, the energy spread at the linac of the Chinese Spallation Neutron Source has been inadequately measured due to limited methods...
Beam loss reduction is essential to achieve higher beam intensity in the main ring synchrotron (MR) of the Japan Proton Accelerator Research Complex (J-PARC). We have observed the effect of the third order non-structure resonances of 3νx=64 and νx+2νy=64. The resonance driving terms were measured with the current settings of the trim coils of the sextupole magnets. Both resonances have been...
High-intensity ion beams are inherently subject to significant space charge effects, which lead to complex beam dynamics and emittance growth, particularly in the Low Energy Beam Transport (LEBT) region. In this study, the dynamics and optimization of space charge compensation (SCC) of a high-perveance proton beam are investigated through a combination of 3D numerical modeling and...
The characterization of particle distribution in phase space and its evolution along the beamline is fundamental for accelerator beam commissioning and analysis. While numerical simulations enable straightforward tracking in phase space, experimental reconstruction of phase space distributions remains challenging, particularly for hadron beams where space-charge effects are unavoidable. This...
Based on the beam commissioning of CSNS-I RCS, the current tune above the half-integer resonance exhibits extremely narrow parameter margins and severe instabilities. Therefore, to further increase the beam power in Phase II, significant optimization of the tune is required.
First, we conducted a series of simulations. A total of 97 tunes were selected on the resonance diagram, and the beam...
The Institute of Modern Physics (IMP) has independently developed a conduction-cooled superconducting electron linac prototype without liquid helium. The prototype, based on a 650 MHz (β = 0.82) SRF cavity, successfully accelerated 200 mA, 60 keV, 2 µs pulsed beam to 4.6 MeV with stable operation, demonstrating the feasibility of high-current acceleration.
Building on this achievement, an...
Accurate simulation of high‑brightness, high‑intensity hadron beams is essential for the design, commissioning, and optimization of modern accelerators such as the LHC injector complex, the LHC, and future high‑energy machines. Beam dynamics is governed by complex multiparticle effects, including space charge, impedance‑driven instabilities, intrabeam scattering, beam–beam interactions, and...
In modern proton accelerators, the survivability of beam-intercepting devices, such as targets, beam windows and beam dumps, under intense beam irradiation is a key factor limiting the achievement of higher beam power. To address this global challenge, Radiation Damage in Accelerator Target Environments (RaDIATE) collaboration was established, with Fermilab acting as the leading institution....
Growing demands on accelerator performance, together with recent advances in computational sciences, provide a remarkable opportunity to rethink how CERN’s accelerator complex is operated. Moving beyond traditional approaches, greater automation and improved optimisation methods promise measurable benefits, including reduced costs and energy use, shorter setup times, consistent beam quality,...
We present the Geoff framework for automated accelerator tuning, demonstrated in real-world experiments at GSI. Using classical optimizers like BOBYQA, Geoff enables fast deployment, control room integration, and efficient beam optimization, reducing SIS18 injection losses from 45% to 15% and speeding up FRS setup.
This work also reports the first application of multi-objective and...
Reconstructing the full 6D phase space of a particle beam is a significant challenge, particularly the longitudinal (z–pz) component, which is difficult to measure without interfering with beam operation. We explore the use of artificial intelligence to infer this hidden information from more accessible transverse projections, such as x–px and y–py phase space images. This “virtual diagnostic”...
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