Compensation of the 3Qy resonance at injection energy in the LHC is of significant interest, given its potential to degrade the lifetime of high-intensity beams. In the absence of dedicated corrector circuits for the 3Qy compensation of each beam at low energy, an alternative approach is needed. Using skew-sextupoles in the four common experimental insertions it has been possible to develop a...
The Radiofrequency Quadrupole (RFQ) is the initial accelerating device in many modern linear accelerators (linacs), such as the European Spallation Source (ESS), where it accelerates protons from 75 keV to 3.6 MeV. Due to its complex geometry, RFQ beam dynamics are typically studied using finite element solvers, which, while accurate, are computationally intensive and unsuitable for online...
HEPS is a nearly finished fourth-generation photon source with a 6 GeV energy storage ring. When machine protection is activated in the storage ring, the low beam emittance causes most particles to deposit nearly vertically on the collimator. This can result in concentrated heating, potentially leading to material melting of the collimator. Thereby, two pre-kickers are used to generate 4.52 µs...
Radio frequency quadrupole (RFQ) is one of the first cavities in a protons or ions accelerator. It aims to focus, bunch, and accelerate the beam, using a high-intensity electric field concentrated between rods or vanes. At CEA, similarly to other labs, a method to evaluate the inter-vane voltage and to tune the cavity (usually with 4 vanes) has been developed, based on the bead pull...
Intra-Beam Scattering (IBS) remains one of the primary mechanisms of emittance blow-up and performance degradation in the Large Hadron Collider (LHC) accelerator chain. The phenomenon is particularly relevant following the recent injector upgrades to achieve the high-brightness beams required for the High Luminosity LHC (HL-LHC) era. Traditional IBS models, as those already implemented in...
The Institute for Nuclear Physics of the University of Mainz operates the accelerator complex MAMI. Outstanding qualities are the continuous beam with an excellent beam quality, a very low energy spread, as well as its extremely high reliability. All kinds of channeling experiments require such a high quality beam with a low divergence. Positrons, however, are more preferable because they have...
The application of a 10 Hz repetitive induction synchrotron (IS) to the next generation of heavy ion therapy drivers is under investigation *. The IS is characterized by the use of a pulse voltage to accelerate the beam, but until now, due to technical limitations, the magnitude of the pulse voltage could not be perfectly matched to the acceleration conditions. Instead, a pulse density...
TM020-mode cavity with a higher quality factor and a lower R/Q as compared to TM010 cavity is an attractive candidate for RF system of Super Tau-Charm Facility. However, the symmetrical electromagnetic field distribution at radial nodes is diluted by the introduction of a high-power input port and cavity frequency tuners. This results in the leakage of the accelerating mode and a weak damping...
To meet the requirements of collider rings of Super Tau-Charm Facility (STCF) with a beam current of up to 2 A, a TM020-mode cavity with improved performance is designed in this paper. In order to address the issues of leakage of accelerating mode into the slots which has dampers inside, a choke geometry is introduced for this cavity. Through optimizations on this choke, the accelerating mode...
The SEALab facility in Berlin is home to an R\&D superconducting radio-frequency (SRF)photoinjector setup and beamline. Designed to support multiple varied applications - ranging from Energy Recovery Linac (ERL) to Ultrafast Electron Diffraction (UED) and Electron-Beam Water Treatment (EBWT) - SEALab requires flexible, high-precision tuning to support these diverse beam modes. These...
Accurately simulating the thermal and mechanical effects of undulator power density distribution in high heat load components requires precise power implementation in finite element analysis (FEA) models. This study presents a novel methodology utilizing intermediate programming to efficiently map complex undulator power density distributions onto FEA models. The approach enables the placement...
For years, Instrumentation Technologies and ScandiNova have developed advanced products to optimize RF performances in LINAC applications. In 2024, the companies began integrating the Libera LLRF system into ScandiNova modulators during assembly. This innovation enables the modulators to offer enhanced operational flexibility and improved performances.
This paper will focus on mechanical...
The Karlsruhe Research Accelerator (KARA) has undergone a significant modernization of its power supply infrastructure, including dipole, quadrupole and sextupole magnet systems. These updates, completed by replacing the storage ring quadrupole power supplies in summer 2024, introduce improved stability, reduced energy consumption, and advanced control capabilities.
The new controls and...
Dynamic aperture (DA) is a crucial metric for understanding nonlinear beam dynamics and particle stability in circular accelerators like the Large Hadron Collider (LHC) and its future High-Luminosity LHC (HL-LHC) upgrade. Traditional methods for DA evaluation are computationally intensive, requiring extensive tracking of large particle ensembles over many turns. Recent advances in machine...
This study explores beam dynamics in the development of high intensity cyclotrons, focusing on the challenges posed by space charge effects at high beam intensities. Space charge forces, which become significant in high-current operations, can lead to emittance growth, beam loss, and instability, compromising cyclotron performance. Advanced modeling techniques are employed to analyze and...
The KIT cSTART project (compact STorage ring for Accelerator Research and Technology) aims to demonstrate the injection and storage of a high intensity ultra-short electron bunch in a large acceptance storage ring using the FLUTE linac and a laser plasma accelerator (LPA) as injectors. Amongst the unique features of the cSTART project is the wide dynamic range of machine and beam parameters to...
Manipulation of an electron beam by Laguerre-Gaussian (LG) modes is investigated using finite-difference time-domain particle-in-cell (FDTD-PIC) simulations. The azimuthal velocity profiles of macro-particles exhibit a 3-D spiral pattern with the number of strands equal to a sum of the state number of spin angular momentum and the orbital angular momentum of LG modes. These spiral patterns...
The transverse beam halo population in the Large Hadron Collider (LHC) has been found to carry a significant fraction of the total stored beam energy, potentially reaching several percent. With the anticipated increase in beam brightness for the High Luminosity LHC (HL-LHC), this poses an increasing risk to machine safety, particularly during abrupt orbit shifts or critical component failures....
The low-frequency components of the impedance drive coupled-bunch instabilities in electron synchrotrons. In the Diamond-II storage ring, the geometric component of the impedance of some vacuum vessels is comparable in strength to the resistive-wall impedance. This study compares the growth rates of all coupled-bunch modes obtained through simulations and analytical calculations....
SRF cavities deteriorate in efficiency over time and need for inexpensive cleaning methods that are effective is apparent. Plasma Processing is one such cleaning method that can be implemented in-situ, reducing the processing time taken drastically. In this work we present our analysis of the higher order modes of the 72 MHz QWR at ATLAS, ANL for use in igniting plasma for cavity processing.
This paper presents observations collected during the LHC operation with proton beams in 2024. In particular, a systematic analysis of the beam and machine parameters along the run reveals that the emittance evolution at the LHC injection plateau and during collisions cannot be fully explained by Intra-Beam scattering, synchrotron radiation and electron cloud effects, thus indicating that some...
The Hefei Advanced Light Facility (HALF) storage ring employs a hybrid six-bend achromat lattice with long and short straight sections. In this paper, main resonance lines of on- and off-momentum dynamic apertures (DAs) of the HALF lattice are analyzed by using frequency map analysis and considering $\beta$-beat. The combined effect of a fifth-order structural resonance and a half-integer...
In the present study we provide a simple model and a physics insight into the recently discovered Skew Wakefield Effect*. We show that the effect posses certain complexity as along with the rotation of the principle axis of the quadrupole wake there exist an overall increase in the wake transverse wake amplitude.
SLAC has been developing the parallel finite element electromagnetics simulation suite ACE3P (Advanced Computational Electromagnetics 3D Parallel) for accelerator modeling using high performance computing (HPC) platforms. In this work we present the current status of the development of the nonlinear EM solver, in ACE3P which includes nonlinear material with application to quantum nonlinear...
Total electron emission yield (TEEY), defined as the number of electrons emitted per incident electron of a given energy, is potentially the source of two major problems: electrostatic discharges (ESD) in vacuum and multipacting effect. To mitigate these risks, a possible solution could be to coat the surfaces prone to ESD or multipacting originate with a thin film with tunable TEEY and...
AtomicAndPhysicalConstants.jl is a Julia package designed to provide atomic and physical constants including the speed of light, subatomic particle properties, atomic isotope properties, etc. Values are obtained from CODATA (Committee on Data of the International Science Council), NIST (National Institute of Standards and Technology), and PDG (Particle Data Group) datasets for physical...
A novel wireless method for beam coupling impedance measurements is currently under development, with preliminary measurements on beam pipes serving as proof of concept for its validity. This innovative approach overcomes the limitations of existing methods by not only evaluating impedance with high accuracy but also enabling the characterization of an unknown Device Under Test (DUT) as it...
The side-coupled standing wave accelerator tubes have a wide range of applications in linear electron accelerators due to their relatively high acceleration gradient and relatively low sensitivity to manufacturing errors. In the NSTRI-eLinac project, a dual energy electron linear accelerator is defined for cargo applications. In this accelerator, a side-coupled standing wave tube accelerates...
Developing medical accelerators for clinical use presents significant challenges, particularly for FLASH radiotherapy, where specific beam parameters are essential to activate the FLASH effect. At Sapienza University, a new electron FLASH LINAC is being developed, designed to deliver FLASH electrons and adaptable for very high-energy electron (VHEE) applications. This work focuses on...
A series of experiments has been carried out at CERN to derive the damage limits of superconductor strands and sample coils. The latest experiment was designed to characterize the limits of Nb3Sn racetrack sample coils impacted by a 440 GeV/c proton beam at cryogenic temperature. The effect of a beam impact on superconducting coils aged by long-term radiation exposure, however, is currently...
In view of ensuring the successful completion of the third operational run of the Large Hadron Collider (LHC) and preparing for the High-Luminosity LHC era, a systematic assessment of the risk of failure of all the vacuum interconnection modules installed in the accelerator is being carried out. This was prompted by a significant pressure rise in 2023, localized near an interconnection module...
The J-PARC Main Ring achieves a high extraction efficiency of 99.5% during 30 GeV slow extraction at the current beam power of 80 kW. However, at beam powers above 30 kW, we observed ring-wide beam losses due to transverse beam instability associated with vacuum pressure rises and electron cloud effects, which are believed to be triggered by longitudinal microwave structures. To achieve stable...
The main ring synchrotron (MR) of the Japan Proton Accelerator Research Complex (J-PARC) provides high power proton beams to neutrino and hadron experiments. Since we are planning to increase the beam intensity from current $2.3 \times 10^{14}~$protons per pulse (ppp) to $3.3 \times 10^{14}~$ppp, we need to reduce the beam loss. In the J-PARC MR, the space charge is one of the main causes of...
The components of the SIS100 synchrotron (FAIR facility) are presently under installation in the accelerator tunnel. The superconducting dipole magnets have been produced and the magnet field errors up to 7th order have been measured for all magnets. The superconducting quadrupole magnets are under production, the field error data for a part of the magnets is available. As a part of the magnet...
The PUMA (antiProton Unstable Matter Annihilation) experiment at CERN aims to explore the interaction of antimatter with exotic isotopes, utilizing the unique capabilities of CERN’s ISOLDE facility and Antiproton Decelerator. This contribution presents recent advancements in the beam transfer lines optics studies relevant to the success of the experiment, and to ISOLDE’s operation in general....
The Delhi Light Source is an upcoming user facility for coherent THz radiation and electron beam. Electron beam of energy upto 8 MeV generated from a RF photo-cathode gun will be used for coherent THz generation from a planer undulator. The beam after passing through the undulator field will be separated from the THz and THz line by a $60^{o}$ achromatic section and delivered to electron...
Optics studies in the LHC are generally performed on low-intensity, non-colliding beams. Understanding the optics perturbation from beam-beam effects however, is of significant interest. This was particularly true for the LHC in 2024, where the 3Qy resonance driven by the long-range beam-beam (LRBB) contributed to breaking of the collimator hierarchy, limiting beta* reach and luminosity. By...
SIRIUS is the 4th generation synchrotron light source of the Brazilian Synchrotron Light Laboratory (LNLS). In mid 2024 the storage ring had a major upgrade on the rf system, with the replacement of the PETRA 7-Cell rf cavity by two superconducting (SC) CESR-B cavities. It was antecipated that after the upgrade the longitudinal coupled-bunch instabilities (LCBIs), previously driven by the...
To achieve the design luminosity of $1 \times 10^{35}\ \text{cm}^{-2}\text{s}^{-1}$, the Super Tau-Charm Facility (STCF) adopts an extremely low $\beta_y^*$ and a crab waist (CW) collision design. The extremely small vertical beam size at the interaction point and low vertical emittance required to achieve a beam-beam parameter of around 0.1 make the CW colliders highly susceptible to beam...
Effect of the transverse instability driven by the resistive wall impedance in the PF-HLS (Photon Factory Hybrid Light Source) 2.5GeV storage ring are investigated and compared with three methods: an analytical method with azimuthal modes, a Vlasov solver DELPHI and beam tracking code MBTRACK2**.
The PF-HLS is proposed as the successor machine to the PF-2.5GeV ring and the PF...
Intra-beam scattering (IBS) has recently gained significant interest in the community of free electron lasers (FELs), as it is believed to produce an increment in the sliced energy spread (SES), which is detrimental to FEL performance. To control and contain this phenomenon, it is important to include IBS in the design phase of an FEL through appropriate numerical simulation. Most existing...
Observations of betatron tune evolution during LHC beam injection have revealed a significant tune error, strongly correlated with beam intensity. This finding highlights limitations in the existing feedforward corrections based on Laslett coefficients. A dedicated machine development study was conducted to refine intensity-dependent tune corrections. Utilizing high-precision, per-bunch tune...
The 4th generation synchrotron light source, BESSY III, is expected to enable high-impact applications for users in life science, material science, energy and catalysis materials, and more. Currently in its Conceptual Design Report (CDR) phase, the feasibility of BESSY III's ambitious parameter range necessitates a thorough assessment of "collective effects". These phenomena can either...
Currently in its Conceptual Design Phase (CDR), the 4th generation light source BESSY III aims to become a world-leading soft X-ray source, enabling numerous applications in metrology, life sciences, energy and catalysis materials, and many more. Its performance relies on ultra-low transverse emittances, achieved through the use of strong focusing magnetic elements that are sensitive to...
The CERN-SPS transverse impedance model plays an important role in predicting beam stability and guiding machine operation. This work advances the benchmarking of the SPS vertical impedance model through experimental investigations of mode-zero instability growth rates and intensity-dependent tune shifts as a function of chromaticity. Building on insights from previous measurement campaigns,...
Controlled longitudinal emittance blow-up is indispensable for the operation of the Large Hadron Collider (LHC) to counteract single-bunch loss of Landau damping during the acceleration ramp. The blow-up is performed by injecting RF phase noise in a narrow frequency band into the beam phase loop, with bunch-length feedback regulating the noise amplitude. In 2024, the variation of the bunch...
Study of bunch lengthening effect in SSMB storage ring using STABLE program.
Relativistic vortex electrons carrying orbital angular momentum (OAM) may provide a novel tool for applications in atomic, nuclear, and particle physics. A straightforward approach to produce such particles involves generating vortex electrons using conventional methods, such as fork-like holograms or magnetic monopoles, followed by their acceleration in a linac. While the azimuthal symmetry...
The CERN Proton Synchrotron Booster (PSB) delivers a wide variety of high-intensity and high-brightness proton beams to several destinations, including operations at the Large Hadron Collider (LHC) and various fixed-target experiments. Following the Long Shutdown 2 (LS2) upgrades, discrepancies between beam measurements and macro-particle simulations were observed, highlighting the need for a...
To enhance the performance of superconducting radiofrequency (SRF) cavities, a promising solution involves depositing a superconducting material onto copper RF cavities. A prerequisite for this process is the electropolishing of the copper cavities. At Jefferson Lab (JLab), a modeling study of the electropolishing process for 1.3 GHz copper cavities was conducted. This paper focuses on two...
The 5 MeV beamline of Phase B+ which is an intermediate commissioning stage of the Linear IFMIF Prototype Accelerator (LIPAc) consists of an MEBT, an MEBT Extension Line (MEL) where the SRF will be installed, a HEBT, and a beam dump. It has 17 quadrupole magnets, and some quads have small aperture-to-length ratios and are also densely installed in the MEBT and HEBT sections. In the early...
The purpose of this research is to characterize proton beam properties - beam energy, energy spread, beam size, and transverse emittance - to establish the initial setup for simulation in planning cancer cell culture experiments at the Cyclotron Medical Accelerator at King Chulalongkorn Memorial Hospital in Bangkok, Thailand. The characterization was performed using GEANT4 Monte Carlo (MC)...
We study the coherent synchrotron radiation instability in a novel synchrotron light source concept, steady-state microbunching storage ring.
One of the major goals of the cSTART project (compact STorage ring for Accelerator Research and Technology) at KIT is injecting and storing ultra-short bunches from the FLUTE linac into a very large-acceptance compact storage ring. To cope with the spatial constraints of the injection line connecting FLUTE with the storage ring three meters above, compact quadrupole-sextupole magnet units were...
The analysis and mitigation of collective beam effects, such as coherent synchrotron radiation (CSR), is a significant challenge in the generation of high-brightness beams. To this end, considerable effort has been invested in the development of simulation tools to accurately characterize the CSR generated by a bunch following a curved trajectory. In particular, with codes like LW3D and CoSyR,...
Superconducting radio frequency (SRF) cavities are, along with superconducting magnets, indispensable technologies for modern particle accelerators. The current cooling method for SRF cavities is immersion in liquid helium bath, which is ideal in terms of cooling because the entire outer surface of the cavity can be maintained at liquid helium temperature. On the other hand, using helium has...
Superconducting magnets, RF cavities, undulators and wigglers are widely employed for particle accelerators and cooled under the cryogenic condition below 100 K. This paper describes the cryogenic cooling schemes of superconducting devices and the sources of the cooling power capacities: refrigerators, cryoplants, and cryocoolers. Their main features, such as temperature, pressure, and cooling...
In 2023 the beam commissioning of low energy superconducting linear accelerator (SCL3) of a heavy ion accelerator, RAON have been finished in Daejeon, Korea by Institute for Rare Isotope Science (IRIS) in Institute of Basic Science (IBS). The purpose of this accelerator is the generation of rare isotope by ISOL (Isotope Separation On-Line) and its acceleration for the nuclear physics...
Beam-Beam simulations are currently being studied in preparation for future EIC experiments to study beam-beam effects and, in turn, maximize luminosity. Weak-strong methods are studied for single-particle dynamics during collision. 1 million macro-particles for 1 million turns are typically tracked, corresponding to only 10 seconds in the EIC. The goal of this study is to predict beam...
The SHINE project requires more than six hundred of 1.3GHz cavities and sixteen 3.9GHz cavities for the superconducting accelerator. These cavities are from both domestic and foreign companies. Surface defects, such as cat-eyes, aluminum inclusions and scratches, are one of the most important factors strongly related to RF performance of cavities. The multiplicity of sizes, depths and...
In recent years, several new beam manipulation techniques have been proposed that exploit the crossing of nonlinear resonances and the use of stable islands of the transverse phase space. One such manipulation is a novel approach to slow extraction, which combines particle trapping in stable islands with the use of bent crystals to reduce losses on the extraction septum. As a first step...
The permanent-magnet in-vacuum undulator technique is critical for the Taiwan Photon Source(TPS) at the National Synchrotron Radiation Research Center(NSRRC). Before installing the magnet arrays in the vacuum chamber, the phase error of the undulator is optimized by adjusting the magnetic field. Optimizing phase errors is a complex and time-consuming task. The conventional measurement method...
SCK CEN is developing MYRRHA, a large-scale Accelerator Driven System. MYRRHA shall be a subcritical nuclear reactor driven by a high-power linear proton accelerator, which sustains the nuclear reaction. In the initial phase, known as the MINERVA project, the goal is to demonstrate the high reliability requirements on the accelerator. The two primary end users of the MINERVA project are the...
This paper presents the design and implementation of a power distribution and monitoring system for a high-power RF solid-state amplifier (SSPA) system at the Taiwan Photon Source (TPS). The system consists of four SSPA towers delivering a combined RF power of 300 kW. Given efficiency and safety considerations, a robust distribution and protection architecture was implemented. The system...
The growing interest in dual-mode microwave structures has led to a surge in research efforts. A critical challenge in their application is the efficient transfer of microwave power with various frequencies. One approach to this issue involves the utilization of intricate waveguide components, such as a dual-mode electron gun that operates at both the fundamental and second harmonic...
The RF window has to withstand several megawatts of RF power without experiencing any physical deformity to maintain the pressure difference between vacuum and isolate gas sides. It must also have suitable and acceptable RF performance with minimum reflection and insertion loss. The design of an RF window depends on the window materials' dielectric characteristics, such as dielectric constant,...
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...
RF loads are critical components in any high-power rf system. There are two types of commonly used rf loads in multi-megawatt systems: water loads and dry loads. Water loads have a ceramic window separating vacuum from the water. Use of water loads in large scale rf systems is risky because of the possibility of water leaking into vacuum. At SLAC multi-megawatt dry loads were developed and...
The Super Tau-Charm Facility (STCF) project plans to use 12-15 TM020-mode cavities for each collider ring to compensate for the beam energy loss. Each cavity is designed to provide a voltage of 0.5 MV and a power of 250 kW for the beam. Therefore, an online adjustable waveguide coupler with a power capacity of CW 300 kW has to be developed for each cavity. This input coupler has a waveguide...
In the J-PARC muon g-2/EDM experiment, a three-dimensional beam injection scheme will be adopted to inject a 300 MeV/c muon beam into a compact storage orbit. In this scheme, a low-emittance muon beam with X-Y coupling is injected from the edge of a solenoidal magnet and guided to a compact beam storage region where the magnetic field is precisely tunned for a muon g-2 measurement with a good...
LhARA, which stands for “Laser-hybrid Accelerator for
Radiobiological Applications”, is a novel and flexible facil-
ity dedicated to research in radiobiology. A proton beam
of energy up to 15 MeV can be produced by a laser driven
source, the beam then enters a Fixed Field Alternating (FFA)
gradient accelerator for acceleration to produce a variable ex-
traction energy between 15-127 MeV....
The grid control power supply of the electron gun of the free electron laser (FEL) is a high frequency pulse power supply (HF-PPS), which has a special time structure. The macro pulse repetition frequency of the HF-PPS designed in this paper is 10 Hz, and the micro pulse repetition frequency is 476 MHz.
The high broadband field-gradient RF system based on direct oil-cooling magnetic alloy cavity for High Intensity Heavy-ion Accelerator Facility (HIAF) Bost Ring (BRing) has been successfully reached and developed in Oct. 2022. The RF system consists of a three gaps cavity which loaded by 24 domestic nanocrystalline soft magnetic alloy (MA) ring cores, a RF power amplifier with an output power...
A non-linear kicker (NLK) is designed for the beam injection into the storage ring of Siam Photon Source II. The required deflection angle is 4 mrad, the effective length is 400 mm and the peak field is 100 mT at the horizontal position of 9 mm from the magnet center. The design is based on 8-wire configuration where the conductor position is symmetric along the xz and yz planes. The vertical...
The interaction region IR6 in the Electron Storage Ring of the planned Electron Ion Collider facility at Brookhaven National Laboratory includes a section to rotate the electron spin into or out of the longitudinal direction. This section consists of superconducting solenoids, and normal conducting dipoles and quadrupoles. The geometry and field gradient requirements of the quadrupoles pose a...
Fixed Field Alternating gradient accelerators (FFA) hold
promise for pulsed high intensity applications. No such
FFA has been constructed to date; therefore a prototype -
the Front End Test Stand-FFA (FETS-FFA) has been pro-
posed to explore the feasibility of using FFA technology for
the next generation spallation neutron source, ISIS-II. A key
component of this prototype is its main...
The Siam Photon Source II (SPS-II) represents Thailand’s second synchrotron light source, designed to enhance the region’s scientific capabilities by providing high-energy, high-intensity synchrotron light for both academic and industrial research. The SPS-II will be situated in the Eastern Economic Corridor of Innovation (EECi) in Rayong Province. The SPS-II accelerator complex comprises...
RadiaBeam has designed and manufactured a fast-ramping alpha magnet (FRAM) that is developed for interleaved operation at the Advanced Photon Source (APS) at Argonne National Laboratory. This interleaving operation requires the alpha magnet to stably complete a 5 s long cycle with a 100 ms ramp-up, 1s nominal field output and a 100 ms ramp-down. A laminated yoke is used to minimize eddy...
From 2010, the Institute of Modern Physics (IMP) of the Chinese Academy of Sciences (CAS) carried out the relevant testing and research work on the RF Cavity loaded magnetic alloy materials firstly, and explored the development process of high-performance magnetic alloy (MA) cores with domestic manufacturers and research institutes jointly. Through the long-term exploration from small...
To perform high electric field experiments for evaluating the vacuum breakdown characteristics of accelerator materials, we have developed a high-voltage pulsed power supply capable of providing a 10 kV peak voltage, 1 µs pulse width, and 1 kHz repetition rate. This system is designed to reliably apply intense fields to metallic electrodes with load capacitances up to 650 pF. To ensure...
We have been developing a compact pulse power supply with output pulse waveform specifications of 75kV/40A/50us/25Hz. This power supply is used to drive klystron for muon linac, which requires high stability and reliability. Next-generation power semiconductor SiC-MOSFETs with excellent characteristics of ultra-high breakdown voltage and low loss at 13kV, which were realized through the...
This study presents a multi-module parallel current output system based on the correction magnet power supplies (CMPS) of the TPS storage ring. An N+1 re-dundant control interface card was designed to enable high-current, bipolar modular parallel output. The system integrates external DCCTs and current feed-back signals from the internal module. After PI com-pensation, these feedback signals...
The R&D of the radio frequency (RF) power distribution system (PDS) for the International Linear Collider is ongoing. The PDS is designed to drive 39 superconducting RF (SRF) cavities by a 10 MW multibeam klystron. The key feature of the PDS is the usage of power dividers and phase shifters, which allow driving all cavities below their respective operational limits over the whole flattop. This...
The China Spallation Neutron Source Upgrade Project (CSNS-Ⅱ) will use two debuncher cavities to supplement the beam energy at the end of the linear accelerator. The PI mode structure operating at room temperature is chosen, and each debuncher cavity is equipped with an online adjustable waveguide coupler. The main body of the coupler is the WR1500 waveguide, and a hole on the narrow wall of...
Our 6 MeV medical C-band accelerating structure is assembled using the disk-stacked method, where multiple oxygen-free copper components are stacked along the beam axis. The design incorporates the side-coupled (SC) structure and the re-entrant structure with an accelerating gap at the center of the cavity. Due to the complex shape and the large nunber of components, there are challenges in...
Currently, pulsed power supply systems with output power of several GW, output voltage of several hundred kV, and pulse width of 100 ns are difficult to miniaturize and portability is a limitation for industrial applications. We are developing a pulsed power supply with an output power of 4 GW, an output voltage of 200 kV, and a pulse width of 100 ns, which is 1/20th the mass of conventional...
We have been developing an X-band transverse deflector system (XB-TDS) with sub-fs time resolution, which will be installed after the undulator sections at SACLA. A sub-fs XFEL pulse is desirable for user experiments such as the measurements of structural disordering in an XFEL interaction with a matter, as the degree of damage depends on the pulse duration. The demand for a shorter and...
Hefei Advanced Light Facility (HALF) consists of two main components: the injector and the storage ring, the core of the facility includes nearly one thousand magnets, of which there are more than one hundred conventional dipole magnets and longitudinal gradient bend magnets.The longitudinal integral field and its uniformity of these dipole magnets are typically measured by the Hall probe...
A stretched wire measurement system was developed for magnetic field measurement of magnet prototype for Siam Photon Source II. It is used for magnetic field integral measurement for characterization of multipole field errors, magnet centering and fiducialization of multipole magnets. The wire trajectory across magnet aperture can be either linear or circular. The maximum wire movement is ±100...
The power coupler is one of the most important components for superconducting cavities. Different from the normal conducting cavity, the superconducting cavity has to keep an ultra-high cleanliness environment for operation. As the vacuum barrier, power couplers are welded by many different materials and maybe the gas source since they are installed to the cavities after vertical test,...
We have developed a new SLED-type RF pulse compressor for powering ultra-high gradient X-band photoinjectors with pulse lengths shorter than 10 ns. Klystrons capable of generating these short pulses at multi-MW levels are non-existent. However, RF pulse compression is an alternative technique used to increase klystron output peak power at the cost of pulse length. Over the years, we have...
In the International Linear Collider (ILC) main linac, superconducting quadrupole (SCQ) magnets combined with dipole correctors, together with superconducting radio frequency (SRF) cavities, will be used to transport and accelerate electron and positron beams to the collision point. The SRF cavity accelerates the beam up to 125 GeV per side, the SCQ focuses the beam, and the dipole collectors...
Coherent Synchrotron Radiation (CSR) plays a critical role in beam dynamics, significantly influencing beam shape and energy characteristics in particle accelerators. This study investigates the CSR effect through a comprehensive numerical approach, starting from the fundamental Lienard-Wiechert equation and utilizing an explicit, non-approximated methodology to explore beam energy dynamics....
The evaluation of dynamic aperture (DA) under time-dependent variations of lattice parameters is essential for understanding the long-term stability of particle motion in the Large Hadron Collider (LHC) and enhancing the future performance of the High-Luminosity LHC (HL-LHC). In this work, we develop DA models that address the complexities introduced by time-varying effects, with a focus on...
The dynamic aperture(DA) is one of the most important parameters of nonlinear beam dynamics in storage rings. It describes the transverse phase space region where the motion of a particle can remain stable. In the design and optimization of storage rings, long-term particle tracking is usually required to ensure an sufficient DA. However this process is very time consuming. This study explores...
We simulated the dynamic problems in the SSMB storage ring, such as TMCI, through the dynamic simulation software elegant and discovered its instability threshold current intensity.
C-band technology holds the potential to generate a high-energy, high-brightness electron beam by elevating the peak field of both the cathode and cavity within the machine. This proposed injector offers a promising avenue for achieving kHz operation. The conceptualization of this injector draws inspiration from the EuPRAXIA@SPARC_LAB S-band injector, wherein the gun is replaced with a...
Coupled bunch instability was observed during beam commissioning of CSNS/RCS. The instability was successfully suppressed by installing sextupoles to control chromaticity. The instability exhibits characteristics influenced by the strength of space charge. We conducted a theoretical study on the effects of chromaticity and space charge on coupled bunch instability and compared results with...
The behavior of high gradient rf cavity is improved via the reduction of RF breakdown rates by operating at cryogenic and temperatures. These studies are largely empirical but they present a new paradigm in the future of high gradient capital operation. Peak electric fields >200 MV/m are sustainable at S and C band frequencies. These fields while sustainable produce more dark current than is...
Recently, two SIRIUS hard X-ray beamlines, EMA and PAINEIRA, were upgraded by replacing their previous insertion devices (IDs) with SIRIUS’s first in-vacuum undulators (IVUs). These new IDs have a period of 18.5 mm and can achieve a peak magnetic field of 1.24 T at a minimum gap of 4.3 mm. This paper reports on the effects of these new light sources on the electron beam, including static and...
For the upgrade of SOLEIL II a new booster with reduced transverse and longitudinal beam sizes is required. The new booster follows a 16 BA Higher-Order Achromat lattice with a reduced emittance to about 5 nm rad at 2.75 GeV. At the end of the ramp an emittance exchange is foreseen to allow for more flexibility in the injection parameters into the storage ring. In order for a good efficiency...
Fast orbit feedback systems are an important component in fourth-generation synchrotron radiation sources such as PETRA IV at DESY in Hamburg, Germany. These control systems are designed to stabilize the particle orbit, i.e., to correct deviations from the design orbit due to various disturbances. To that end, such a system employs fast orbit corrector magnets, which must be powered at...
Recently, artificial intelligence and machine learning are actively discussed in the particle accelerator community. The physics-informed neural network (PINN) method, which is a powerful approach for solving differential equations with deep neural networks (DNN), has been successfully applied to the calculation of electromagnetic fields and beam coupling impedances in particle accelerators....
The Future Circular Collider (FCC)-ee is a planned electron-positron collider under development. The future collider would be built in an about 91 km ring-shaped underground tunnel located beneath the French departments of Haute-Savoie and Ain, and the Swiss canton of Geneva. The FCC-ee may face challenges from electron cloud (e-cloud). The strongest effects are foreseen for the Z...
The Taiwan Photon Source (TPS) booster ring accelerates electron beams from the linear accelerator (lin-ac) output energy of 150 MeV to 3 GeV for storage ring injection. In the event of partial RF station failure in the linac, the available beam energy may be reduced to 100 MeV. Preliminary machine tests have demonstrated multi-turn beam circulation in DC mode and successful acceleration from...
Graphical user interfaces (GUIs) are sought to support particle accelerator and beamline modeling for both conventional and advanced accelerator concepts. Downloaded over 1500 times in the last 22 years, G4beamline (available gratis from Muons, Inc.) has been used for diverse applications in science and industry, representing over 50M$ of economic activity. Its strengths include ease of use...
Recently, many new light source projects have been developed based on the Multi-Bend Achromat (MBA) magnet lattice. In general, the dynamic aperture and transverse emittance of synchrotron light sources are sensitive to errors in magnet fields, alignment, and momentum. A realistic estimation of error tolerances is crucial for the successful construction of a fourth-generation synchrotron light...
The first section of the ESS superconducting linac is the Spoke Linac, which raises the beam energy from 90 MeV to 216 MeV. This is achieved by 26 superconducting spoke cavities, housed in 13 cryomodules. These cavities are powered by Spoke RF Power Stations (RFPS), each delivering a maximum power output of 400 kW at 352 MHz. This power is generated by combining the outputs of two tetrode...
The European Spallation Source (ESS) superconducting linear accelerator (linac) represents a key component in delivering high-intensity proton beams for cutting-edge neutron science research. This paper details the first cold technical commissioning of the superconducting linac in 2MW configuration, focusing on the performance validation of cryomodules, superconducting radio-frequency (SRF)...
At the large synchrotron radiation facility SPring-8, the upgrade project “SPring-8-II” is underway to increase the radiation brightness by 100 times. In SPring-8-II, the beam energy will be reduced from 8 GeV to 6 GeV and the beam current will increase from 100 mA to 200 mA. The bell-shaped 509 MHz cavities will remain in place at SPring-8-II, with the number of cavities reduced from 32 to...
In a collaborative work between ALBA and KEK the computation of the microwave instability threshold of the current ALBA ring was initiated. This analysis involves solving the dispersion relation equation and conducting simulations using a Vlasov-Fokker-Planck (VFP) solver. The longitudinal wake fields of geometric origin of all vacuum elements were computed with GdfidL** using a bunch...
The J-PARC Main Ring (MR) RF system has been undergoing upgrades in preparation for the Hyper-Kamiokande (Hyper-K) neutrino experiment, which is scheduled to begin receiving a 1.3 MW proton beam in 2028. The beam will be accelerated from 3 GeV to 30 GeV within the MR over a reduced cycle time of 0.58 seconds, down from the current 0.65 seconds. Additionally, the number of protons will be...
In a linear accelerator (linac), having a reliable model of the accelerating cavity is critical, as it is the primary element influencing particle dynamics. At the European Spallation Source (ESS), the TraceWin software is used for linac design, implementing thin-gap and multi-cell models, with both linearized matrix-based and field-map solvers. However, these models cannot be used online, as...
Longitudinal emittance growth is a significant challenge in RF linacs, especially for poorly bunched beams. This stems from particles occupying outer synchrotron oscillation orbits in the LBET, causing unwanted bunch-bunch interactions and degraded beam quality. To address this, we proposed using temporally spaced laser pulses to selectively photo-detach electrons from the longitudinal head...
The Karlsruhe Research Accelerator (KARA), a synchrotron light source and test facility, at the Karlsruhe Institute of Technology (KIT), offers excellent conditions for testing different Beam-Based Alignment (BBA) approaches. Classical BBA approaches estimate the offset between the magnet and the closest BPM for one magnet at a time, and the required time for the BBA scales linearly with the...
Hefei Advanced Light Facility (HALF) is a 2.2 GeV diffraction-limited storage ring designed with a modified hybrid six-bend achromat (H6BA) lattice. The present baseline lattice has a relatively large dynamic aperture and a reasonable Touschek lifetime. But it is better to further improve the nonlinear dynamics performance when considering the effect from errors and insertion devices. For a...
Symplecticity of the transfer maps is important for reliable evaluation of space-charge dominated beams in accelerators. Unfortunately, most simulation codes that include collective effects, such as space charge, do not use canonical phase-space variables and therefore are not symplectic in the presence of electromagnetic fields. In this paper, we present a numerical method to extract...
Magnetic fields play an important role in many physics studies, and many measurement items in physics experiments require control of micro magnetic fields. Although superconducting accelerating cavities can generate high electric fields at low power, the material niobium is a type-II superconductor, and trapping the ambient magnetic flux during the superconducting transition increases the...
Structure-based wakefield accelerators (SWFA) have been identified as a candidate technology for future applications ranging from free electron lasers to colliders. However, achieving the desired beam energy and quality requires meter-scale structures with tight tolerances, placing constraints on structure and beam characteristics to minimize emittance growth and combat transverse...
Superconducting undulators (SCUs) may be capable of generating stronger magnetic fields at shorter periods than can be achieved using permanent magnet undulators. Therefore, the range of x-ray wavelengths that an XFEL facility can generate for users could be expanded by exploiting SCU technology.
Prototyping work is ongoing at STFC to build a helical superconducting undulator (HSCU) with 13...
The Future Circular Collider (FCC) study is developing designs for higher performance particle colliders that could follow on from the Large Hadron Collider once it reaches the end of its high-luminosity phase. In particular, the FCC-ee is a proposed electron-positron collider that may face challenges from the electron cloud (e-cloud). Specifically, the Z configuration foresees the highest...
Superconducting radiofrequency cavities made of bulk Nb are reaching their theoretical limits in the maximum accelerating gradient, Eacc, where Eacc is limited by the maximum magnetic field, B, that can be applied on the surface of the accelerating cavity wall. To increase Eacc, the maximum B field, Bmax, which can be applied to the surface, must also be increased. The A15 materials or...
The first experimental observation of a 10 $\mu$m crabbing orbit at 1~$\sigma_z$ induced by head-on collisions with a non-zero crossing angle ($\theta_c$) in a high-energy proton beam at the LHC is presented. This challenging measurement required both the design of a dedicated experiment and a careful calibration and optimization of the beam instrumentation to produce and detect such a subtle...
The microbunching instability (MBI) has long been a persistent issue in high-brightness electron beam transport. The dogleg structure, a dispersive configuration composed of two quadrupole magnets and dipole magnets, has drawn attention in recent studies. It has been pointed out that the Landau damping effect can be enhanced to effectively suppress the microbunching instability by adjusting...
Oriented bent crystal planes can deflect charged particles as strongly as a magnetic field exceeding 100 T. As a result, beam extraction from an accelerator using oriented crystals offers significant opportunities for diverse applications, ranging from beam tests for particle detector R&D to high-energy fixed-target experiments. However, designing these applications requires a universal...
Longitudinal tomography is widely used in the CERN synchrotrons as an essential beam diagnostics tool. In recent years, more complex applications of phase space tomography, such as voltage calibration and multi-bunch tomography, have been explored. For these applications, large numbers of reconstructions are required, and computation time has a significant impact on usability. The current...
Longitudinal single-bunch instability caused by high-frequency impedance poses a major challenge for achieving optimal performance in fourth-generation synchrotron light sources and future electron-positron colliders. Accurate simulations of this instability are critical but computationally intensive, requiring millions of macro-particles and dense slicing to resolve bunch density...
We present a method of constructing a nonlinear accelerator lattice that has at least one approximate integral of motion that is given upfront. The integral under consideration is a Hamiltonian in normalized (canonical) coordinates that is preserved by a lattice with a given accuracy. A connection between the integrator of a Hamiltonian in normalized coordinates and a real lens arrangement is...
After the magnet is magnetized, due to the characteristics of the magnetization curve, there will still be residual magnetism in the magnetic field even after the magnetizing power supply is turned off. When measuring the same magnet multiple times, the residual magnetism not only affects the measurement of the magnetization curve but also impacts surrounding devices and instruments. In the...
Recent efforts at SLAC aim at developing high-power accelerators powered by compact, high-efficiency rf sources such as klystrons and Inductive output tubes (IOT). In particular, a high-efficiency IOT is an electron-beam-driven RF source employed in the UHF band that offers high efficiency at variable output power levels. In this talk, we show the progress of developing a 1.3 GHz HEIOT in...
As the High Luminosity LHC (HL-LHC) era approaches, precise control of the accelerator becomes increasingly critical. Machine studies are essential to address the forthcoming challenges and develop correction strategies based on experimental measurements. Although the upgraded inner triplets are not yet available, key features of the HL-LHC optics can still be investigated. This includes...
The high-frequency cavity system of the Wuhan Advanced Light Source (WALS) utilizes a normal temperature single-cell cavity with heavily damped higher-order modes. The operating frequency of this cavity is 499.654 MHz. Power from a solid-state power source module passes through a circulator and then is fed into the main cavity via a waveguide. The coupler is designed to be compatible with both...
A pulsed power supply (PPS) using SiC-MOSFETs is an essential component in the camshaft-bunch system at KEK-PF *. The system requires the PPS to generate half-sine pulses with a peak current of 500 A, a pulse width of 200 ns, and a repetition rate (rep-rate) of 800 kHz. We have developed a prototype PPS consisting of a resonant circuit (RC) to generate half-sine pulses with a SiC-MOSFET...
The X-LAB has been commissioned at the University of Melbourne. A key project within this laboratory involves rehoming half of the CERN high-gradient X-band test stand, XBOX3, now known as Mel-BOX. This initiative aims to validate the performance of high-gradient traveling wave accelerating structures operating at a frequency of 12 GHz. Mel-BOX is employed to evaluate the performance of these...
SuperKEKB is a high-current machine for high-luminosity.Eight higher order mode (HOM) damped single-cell superconducting cavities accelerated an electron beam in the main ring since KEKB.
A strong dependence of the absorbed power of the ferrite HOM dampers on
the number of bunches was observed in 2022 operation. One of the reasons for this is thought to be a build-up effect of some parts of...
We have introduced new 476MHz solid-state pulsed amplifiers to the X-ray Free Electron Laser facility, SACLA. The 476 MHz booster cavity requires high stability and reliability with a 100 kW power for 50 us pulse width. Previously, an Inductive Output Tube (IOT) was employed for this purpose. However, due to the reduced operational range caused by aging of IOT components and increasing...
The SRF community has shown that high temperature annealing can improve the flux expulsion of niobium cavities during cooldown. The required temperature will vary between cavities and different batches of material, typically around 800 C and up to 1000 C. However, for niobium with a low residual resistance ratio (RRR), even 1000 C is not enough to improve its poor flux expulsion. The purpose...
Unipolar and bipolar High Power Impulse Magnetron Sputtering (HiPIMS) are widely used techniques for depositing superconducting thin films, utilizing various magnetron configurations such as planar and cylindrical. In this study, ion energy and flux were measured from both planar and cylindrical magnetrons under varying pressure and power conditions, using mass spectrometry and Retarding Field...
Magnetic field measurements have been performed after fabrication of new separation dipoles for the low beta-star insertion regions of the High Luminosity LHC project*. In this paper, the effect of the linear imperfections of these magnets on coupling, beam size and beta-beating are evaluated using MAD-X simulations. The results indicate that the impact of normal-oriented quadrupole errors are...
Since the start of the third operational run of the CERN Large Hadron Collider (LHC) in 2022, multiple observations have highlighted the significant influence of non-linearities within the accelerator on the collimation loss patterns of circulating beams. Understanding this phenomenon is particularly relevant for qualifying and validating collimation performance for machine operation at high...
The combination of a compact storage ring and a laser-plasma accelerator (LPA) can serve as the basis for future compact light sources. One challenge is the large momentum spread (about 2%) of the electron beams delivered by the LPA. To overcome this challenge, a very large acceptance compact storage ring (VLA-cSR) was designed as part of the compact STorage ring for Accelerator Research and...
Beam stability in the FCC-ee collider is strongly influenced by transverse and longitudinal beam coupling impedance. Developing a flexible and comprehensive impedance model is crucial for accurately evaluating and mitigating instabilities as machine parameters evolve. This study investigates the effect of the FCC-ee collimation system, identifying it as a dominant source of total machine...
To mitigate the risk of radiation damage induced failure while operating the LHC beyond its initial integrated luminosity target, changes to the triplet polarity and crossing angles have been applied in the two main experimental interaction regions of the LHC. This allows for a more distributed radiation deposition in the insertion region magnets, which should allow their survival until they...
The PF Hybrid Light Source (PF-HLS) has been proposed in the High Energy Accelerator Research Organization (KEK), capable of utilizing both high-quality beams from a superconducting linac and beams from a low-emittance storage ring. The coupling impedance will cause beam instability, which must be carefully handled. It is essential to benchmark impedance models using analytical methods and...
Korea-4GSR is a future light source in Korea with a circumference of 800 m, an energy of 4 GeV, and a maximum current of 400 mA. Due to the small aperture of the vacuum chamber (12H x 9V octagonal) and the large number of normal-conducting cavities and beam position monitors (BPMs), impedance-induced instabilities are expected to pose challenges at 400 mA operation. In this study, we estimated...
Over the past year, we have conducted comprehensive impedance optimization calculations for the vacuum components designed for the Hefei Advanced Light Facility (HALF) storage ring. Our calculations indicate that specific components, which have a cavity-like or tapered structure, possibly exhibit a relatively strong trapped-mode impedance in the longitudinal or transverse directions. In order...
The beam wire scanners are instruments for precise transverse beam profile measurements by detecting the secondary particles generated from the interaction of the beam with a moving carbon wire. Following a completely new design of this device for the Large Hadron Collider (LHC), a detailed impedance calculation has been performed already in the design phase. This contribution presents the...
The High Intensity ECN3 (HI-ECN3) project aims to increase the number of protons per pulse delivered to a new experimental facility in CERN’s North Area up to $\sim 4 \cdot 10^{19}$ per year. Such an upgrade requires the reduction of the beam loss at SPS electrostatic septum (ZS) by at least a factor of four, since the activation of this device is the main factor constraining transition to the...
We investigated the effects of low-temperature baking, a standard treatment for superconducting radiofrequency (SRF) cavities, on niobium samples using synchrotron X-ray photoelectron spectroscopy. The study examined the chemical state of the niobium surface after chemical treatment with a buffered etching solution, which leaves a native oxide layer, fluorine impurities, and surface...
This paper reports the status and recent progress of INFN LASA’s in-kind contribution to the PIP-II project at Fermilab, with updates on key activities and major procurements. Production efforts for the 38 INFN LASA-designed, 5-cell cavities (β=0.61) for the LB650 section of the linac are underway and two pre-series prototypes are being realized as a first step to validate the manufacturing...
The ALBA synchrotron light source is undergoing a transformative upgrade to become a state-of-the-art fourth-generation facility, known as ALBA II. This upgrade will reduce the electron beam emittance to approximately 200 pm·rad, achieving a twentyfold improvement over the current performance. A key goal of the project is to maintain the existing source points for the insertion device...
Synchrotron light sources worldwide are transforming into next-generation facilities with ultralow transverse emittances at the diffraction limits. With these parameters, intrabeam scattering (IBS) becomes significant and can spoil the light quality by increasing emittance. A harmonic cavity can be installed to mitigate this effect by increasing the bunch length. Another way to reduce the...
SKIF (Russian acronym for Siberian Circular Photon Source) – is a new fourth generation synchrotron light source under construction in Novosibirsk, Russian Federation.
One of the most important characteristics of the synchrotron radiation source SRF "SKIF", which in turn determines its brightness, is the ultra-low emittance of the electron beam, which depends on the operating regime and...
The determination of electromagnetic wakefields and their impact on accelerator performance is a longstanding challenge in accelerator physics. These wakefields, induced by the interaction between a charged particle beam and the surrounding vacuum chamber structures, significantly affect beam stability and power dissipation. Accurate characterization of these effects via beam-coupling...
The Future Circular Collider is an ambitious international proposal for a next-generation particle accelerator complex, building upon the successes of CERN’s Large Hadron Collider. Specifically, the FCC-ee is a future circular lepton collider. The baseline design for the FCC-ee features four modes of operation, with beam energies ranging from 45.6 GeV to 182.5 GeV. Electron cloud (e-cloud)...
The long injection segment (flat bottom) of the cycle in the Super Proton Synchrotron (SPS) used for filling the Large Hadron Collider (LHC) with Pb ion beams, exhibits strong beam losses and transverse emittance growth. During the 2024 run, large improvements of the beam transmission could be made such that record intensities could be delivered to the LHC. In particular, these improvements...
Alternative configurations around the ATLAS experiment are investigated aiming to reduce muon rates at forward physics experiments such as FASER and SND@LHC. The Geant4 toolkit BDSIM is used to propagate muons through a model of a section of the LHC and the TI12 tunnel, where the FASER experiment is located. We compare the muon rates in BDSIM with FASER data collected during dedicated tests in...
With the increasingly challenging parameters in 4th generation synchrotron light sources, collective effects causing instabilities are putting even stronger limitations on the area of stable operation. The microwave instability (MWI) is a longitudinal single-bunch instability driven by the geometric and the resistive-wall impedances. While the instability typically does not result in a beam...
Space charge limited (SCL) emission is of fundamental importance to vacuum electronic devices, where the self-field of emitted charges limits the maximum current density being emitted from a cathode surface. Traditional modeling of SCL emission using the Child-Langmuir law primarily focuses on electron dynamics, neglecting the role of ions, which can significantly influence emission dynamics....
The variation of polarized light is a critical characteristic of synchrotron radiation sources. To accommodate diverse user needs and enable helicity switching, a soft X-ray beamline has been designed to alternate the helicity of polarized undulator radiation. This is achieved by switching between two undulators, configured to provide right and left circularly polarized radiation,...
Carbon ion therapy is one of the most effective radiotherapy methods for cancer treatment, offering superior dose conformality compared to conventional radiation therapies. The combination of carbon ion treatment with a gantry further enhances treatment effectiveness and safety. When designing a gantry, the magnet aperture must consider both the beam envelope and the beam position errors all...
The mitigation of long-range beam-beam interactions remains a critical challenge for maximizing the luminosity performance of the Large Hadron Collider (LHC). Previous experimental studies have demonstrated that long-range beam-beam wire compensation can effectively counteract long range beam-beam interactions, leading to enhanced beam lifetime and increased integrated luminosity. A...
The measurement of the integral magnetic field in accelerator magnets is crucial for the precise control and operation of particle accelerators. Traditional methods often rely on a fixed distribution of magnetic field sensors or long integral coils. Nonetheless, integral coils are sometimes unavailable in the magnet bore.
This study presents an approach to enhance integral magnetic field...
Addressing electromagnetic compatibility (EMC) issues at the design stage is important. However, for a prototype like the Linear IFMIF Prototype Accelerator (LIPAc) and its RadioFrequency (RF) system providing over 2 MW of RF power, problems during the commissioning have to be expected. Random interlocks and probability of occurrence increasing with the number RF modules, the power level or...
The High-Luminosity LHC (HL-LHC) project aims at increasing beam intensity, hence posing tight constraints on its injector chain. A critical issue in the Proton Synchrotron (PS) is the contribution of numerous pumping manifolds to the longitudinal beam coupling impedance at high frequencies. It causes microwave instabilities that particularly affect ion beams and limit the longitudinal density...
Longitudinal microwave instability has been observed in the J-PARC Main Ring. The longitudinal microwave instability was observed during the debunching process for the slow extraction. This led to electron cloud formation, which can cause transverse beam instability and beam losses. Longitudinal microwave instability was also observed during the latter part of the acceleration for the fast...
The LHC luminosity model is a powerful tool for studying the evolution of beam and machine parameters during the LHC operation. The model includes important effects that are present in LHC operation such as Intra-Beam Scattering, synchrotron radiation and burn-off. By comparing model predictions with experimental data, the presence of additional emittance blow-up and intensity loss mechanisms...
Symplectic simulation of space-charge effects is important for high-intensity particle accelerators. In this work, we propose to use a generative model to efficiently simulate space-charge effects in JuTrack, a Julia-based particle tracking code. The one-step symplectic transverse transfer map of the particles is obtained by differentiating the predicted space-charge Hamiltonian. This model...
In order to develop a lightweight gantry for proton therapy, the canted–cosine–theta (CCT) superconducting magnet was considered to apply in the gantry development. The code MagCCT intended for magnetic field calculation and analysis for CCT magnet is described. The main features of the MagCCT are that it can calculate the magnetic fields of 3 different magnets: curved CCT, straight CCT and...
The National Synchrotron Radiation Research Center (NSRRC) is focused on the application of 2G high-temperature superconducting tape (2G-HTS) for the insertion device in the Taiwan Photon Source (TPS) synchrotron ring. A preliminary design for a 2G-HTS wiggler (HTSW) is being developed, with considerations for sharing the SRF straight-section to make efficient use of space. The target field...
The KIT project cSTART (compact STorage ring for Accelerator Research and Technology) aims to store ultra-short electron bunches in a very-large-acceptance compact storage ring. The magnetic lattice of the storage ring is laid out for a variety of beam optics, including ultra-low positive and negative alpha as well as isochronous optics. These put high demands on the magnet quality and...
The Canadian Light Source has decommissioned three insertion devices in recent years, replacing each with upgraded devices. The decommissioned devices are planar undulators that have seen approximately 15 years of operation in a 2.9 GeV storage ring, two being out-of-vacuum devices with 45 mm and 185 mm periods and one being an in-vacuum 20 mm device. In this paper we present magnetic...
We systematically investigated the effects of various thermal treatments on the superconducting properties of niobium. In this study, niobium is utilized for fabricating nine-cell 1.3 GHz cavities used in particle accelerator facilities. Cylindrical niobium samples underwent the same chemical and thermal treatments applied to superconducting radiofrequency (SRF) cavities, including buffered...
We describe a program to develop 805 MHz magnetron power sources to enable a cost effective one GeV Linac that is capable of CW operation at greater than 50 MW beam power. Compared to the klystrons now used at the ORNL SNS, magnetrons have about a factor of ten lower capital cost ($1/W vs $10/W) and much higher wall power to beam power efficiency (almost 90% vs 50%).
Two applications under...
Past measurements* of coherent synchrotron frequencies at the Photon Factory storage ring revealed that the behavior of measured coherent frequencies could not be well explained with standard 4th-order characteristic equation under conditions close to the Robinson limit. To investigate whether similar phenomenon occurs in other storage rings, we measured the coherent synchrotron frequencies at...
In order to explore an efficient and accurate method for measuring the magnetic field information of accelerator magnets, this paper used the stretched wire system to measure a quadrupole magnet prototype of Hefei Advanced Light Source. In the measurement process, the integral field of the magnet at multiple points was first measured to calculate the magnetic center and multipole components of...
Charged particle bunches traversing cavity-like discontinuities in the beam pipe at relativistic velocities excite electromagnetic resonant modes that can detrimentally affect the dynamics of trailing bunches. This beam-cavity interaction, characterized in the frequency domain through the concept of beam-coupling impedance, poses significant challenges for beam stability and performance in...
Many accelerators have to take microbunching gain into consideration during both design and operation; this typically involves beam parameters where space charge is negligible. However, there are some accelerator designs which involve bunch compression of low energy beams with very low slice energy spread - conditions which may be prone to both microbunching considerations as well as space...
Vacuum vessels of the Diamond-II storage ring feature non-evaporable getter (NEG) coating which cause a resonator-like peak in the longitudinal impedance. This work demonstrates how different parameters of NEG can increase momentum-spread growth. It is shown that the spread of the coating-layer thickness amongst vacuum vessels results in significantly reduced momentum-spread growth. Insertion...
This study presents a multi-objective optimization scheme for ring cyclotron RF cavities, leveraging a neural network ensemble surrogate model. The cavity geometry is parameterized using Non-Uniform Rational B-Splines (NURBS), with control points and weights as design parameters. To reduce the computational cost of direct eigenmode simulations, an ensemble of neural networks trained using...
Elliptical cavity geometries are typically parameterised using a canonical set of variables that define the shape of the cavity half-cells. In multicell cavity optimisation, the mid-cells are modelled with identical dimensions, while the end-cells are optimised to ensure good field flatness. However, manufacturing tolerances can introduce slight variations between individual half-cells, as...
SuperKEKB, a double ring circular collider with 7 GeV electron and 4 GeV positron beams, utilizes “nano-beam collision scheme” in which low emittance beams collide at large crossing angle. Positional fluctuations of the colliding beams are predicted to have a deleterious impact on luminosity; therefore, it is important to measure position oscillation of its superconducting quadrupole Final...
Nonlinear integrable optics is a promising design approach for suppressing fast collective instabilities. To study it experimentally, a new storage ring, the Integrable Optics Test Accelerator (IOTA), was built at Fermilab. IOTA has recently completed its fourth electron run, achieving the design 150 MeV energy and optimal beam parameters. This report presents the results for the...
The Landau states of electrons with orbital angular momentum in magnetic fields are important in the quantum theories of synchrotron radiation at storage rings and in many other areas. In realistic scenarios, electrons are often born inside the field or injected from a field-free region, requiring nonstationary quantum states to account for boundary or initial conditions. This study presents...
The Radio-Frequency (RF) system of the CERN Proton Synchrotron Booster (PSB) features Finemet-loaded cavities that cover a wide range of frequencies. This system generates a significant broad-band longitudinal impedance, which must be mitigated to maintain beam stability, particularly at higher beam intensities. To counteract the induced voltage, a direct RF feedback is employed over the...
The presence of third order horizontal resonance island buckets at the ESRF EBS has been observed in simulations and in the machine. The islands appear at a few mm distance from the core with a specific horizontal tune and octupole setting. When the electrons are kicked with an injection kicker, a fraction of the beam can be captured in the island. The procedures to send the beam into the...
Helmholtz-Zentrum Berlin plans to construct a fourth-
generation greenfield synchrotron light source in the early
2030s to replace BESSY II, a 1.7 GeV machine that has been
running since 1998. The optimization of the linear lattice
already considers non-linear aspects, such as minimizing
the necessary sextupole strength and, for the minimal case
of two families of sextupoles, phase...
Vertical tests of single-spoke resonator type 1 (SSR1) superconducting cavities were conducted in conjunction with high-pressure rinsing (HPR) simulations to assess and improve cavity performance. The quality factor (Q) was evaluated as a function of the accelerating field (Eacc), Lorentz force detuning (LFD), and pressure sensitivity. In the HPR simulations, water droplet dynamics emitted...
The beam lifetime in synchrotron light sources is critically influenced by nonlinear beam dynamics, particularly in low-emittance storage rings where the Touschek effect dominates. At the Taiwan Photon Source (TPS), a third-generation 3 GeV storage ring, optimization of harmonic sextupole magnet strengths has been conducted using Bayesian Optimization (BO) techniques to minimize beam loss...
SuperKEKB continues the operation with the aim of achieving high luminosity. The beam current has already exceeded 1.3 A in the electron ring and 1.6 A in the positron ring. Eight superconducting RF (SRF) systems are operating in the electron ring. The SRF system including cavities, input couplers, HOM dampers, and so on was designed for KEKB and modified to handle the higher beam current of...
Determining the betatronic waist shift and the $\beta^*$ at the interaction points through K-modulation in the Large Hadron Collider presents considerable challenges. This paper introduces a novel method for the measurement of these quantities, based on luminosity measurements and the van der Meer technique for reconstructing transverse bunch profiles.
The strategy involves colliding...
Optimization of dynamic aperture is a challenging aspect of low emittance storage ring lattice design. A large dynamic aperture is favourable for efficient injection and long beam lifetime. Several methods like simple scanning of sextupoles and octupoles strength and genetic optimization with different configurations have been successfully combined to enlarge the dynamic aperture of Elettra...
Initial experimental investigations of transverse beam splitting, carried out at the CERN Proton Synchrotron, have demonstrated that transverse feedback is highly effective in controlling the characteristics of the transversally split beam. The feedback notably improves the intensity distribution among the beamlets and the emittance of the core, which is the portion of the beam remaining near...
In this study, superconducting Nb3Sn films were synthesised on different substrate such as sapphire, diamond turned copper and polished Nb, by DC magnetron sputtering from a single stoichiometric alloy Nb3Sn target. The structural, morphological and superconducting properties of the films were investigated. The effect of different deposition and substrate was examined. The film properties are...
High-power attosecond X-ray pulses play a critical role in many areas of research like ultrafast nonlinear spectroscopy, structural and electronic damage-free X-ray measurements. For free-electron laser facilities, the self-chirping operation mode has been demonstrated as an effective method for generating terawatt-level X-ray attosecond pulses. To compress the bunches under this mode, the...
The optimization of LHC operation is focused on achieving the highest possible integrated luminosity to maximize experimental data collection. Given the limitations of current detector systems, maintaining a constant level of integrated luminosity has become more critical than achieving a high peak luminosity. Techniques such as beta-leveling and separation levelling have already been...
The Helium Light Ion Compact Synchrotron (HeLICS) is an innovative synchrotron design for cancer treatment currently under development in the context of the Next Ion Medical Machine Study (NIMMS) at CERN. As part of the lattice design, the beam size around the HeLICS circumference is evaluated and the optics functions optimized in order to meet the aperture requirements imposed by the magnet...
In low-energy FEL beamlines, like SXFEL-SBP at the Shanghai Synchrotron Radiation Facility and FLASH1 and FLASH2 at DESY, SASE undulators with perfectly reasonable strength may dynamically affect the optics of the Focusing-Undulator-Defocusing-Undulator (FUDU) cells, pre-matched for a given fixed set of undulator parameters, so violently that a dynamical re-adjustment of the FUDU quadrupoles...
Since its official operation in 2016, the Taiwan Photon Source (TPS) has been dedicated to providing a stable and high-quality synchrotron radiation light source. The TPS storage ring is divided into 24 sections, each equipped with 7 sextupole power supply units, totaling 168 units. These power supplies are responsible for delivering precise and stable current to drive the sextupole magnets....
Throughout 2023 and 2024, higher-order mode (HOM) dampers were designed, manufactured and installed on the 100 MHz RF cavities in the 3 GeV ring at MAX IV Laboratory. Cavity HOMs have been the main driving source of longitudinal coupled-bunch modes (LCBM) in the ring. This contribution presents the impact of the HOM dampers via measurements performed on the cavities at different operating...
The main source of beam instability in the J-PARC 3-GeV RCS is the impedance of the eight installed kickers. This arises because one end of each kicker magnet is shorted while the other end is left open during beam acceleration. The shorted-end configuration provides the benefit of power savings during beam extraction from the RCS. However, it also excites beam instability. To retain the...
The Linear IFMIF Prototype Accelerator (LIPAc) in Rokkasho, Japan, designed to accelerate p+ to 4.5 MeV and D+ to 9 MeV at 62.5 mA and 125 mA in Continuous Wave (CW) mode, respectively, is under commissioning and about to enter into its final stages. A high-power test bench was developed for the testing and conditioning of the Radio-Frequency (RF) couplers of the RF Quadrupole (RFQ) cavity....
A 4th generation storage ring based light source is being developed in Korea since 2021. It features <60 pm rad intrinsic beam emittance, about 800 m circumference, 4 GeV e-beam energy, full energy booster injection, and more than 40 beamlines which includes more than 24 insertion device (ID) beamlines. To optimize the beam emittances, longitudinal gradient bending magnet is applied in the...
Beam halo formation is a significant challenge for high-intensity accelerators, as it can lead to performance degradation and radiation safety risks. This study investigates the formation and mitigation of beam halos caused by a picosecond time-delayed laser pulse, which generates a secondary electron bunch in the same RF bucket as the main bunch. The energy difference between the two bunches...
The Hefei Advanced Light Facility (HALF) storage ring employs more than 200 photon masks to shield thermally sensitive vacuum components from synchrotron radiation. The impedance introduced by these masks is highly dependent on their intrusion depth. This paper presents a straightforward method for assessing the requisite intrusion depth and the shielded photon power for individual masks....
Plasma treatment has proven effective in recovering and reducing field emission in the affected superconducting radiofrequency (SRF) cavities. A joint effort is underway between CEA, ESS and INFN to apply this technique to the treatment of elliptical cavities in the ESS linac. This paper presents the work done so far, which aims at both the development of the plasma process for cavities in the...
Beam production through the LANSCE accelerator is currently disrupted due to lack of critical klystrons spares that power the Side Coupled Cavity Linear accelerator (SCCL). The situation is so dire that the facility had to compromise running beam at 100MeV for 2024 run cycle instead of its nominal 800MeV. This project aims to predict the future performance of those critical klystron units...
The efficient transfer of protons from the Proton Synchrotron (PS) to the Super Proton Synchrotron (SPS) is crucial for beams in the Large Hadron Collider (LHC). A particular challenge at the intensities required for the High-Luminosity LHC is the handover from a 40 MHz to a 200 MHz RF system. This requires a non-adiabatic bunch shortening in the PS triggered by a fast RF voltage jump....
The National Synchrotron Radiation Laboratory is constructing a 2.2 GeV diffraction-limited storage ring, the Hefei Advanced Light Facility (HALF), using the modified hybrid 6BA lattice, which consists of a total of 20 cells. The synchrotron radiation primarily covers the vacuum ultraviolet (VUV) to soft X-ray bands. To extend the photon energy into the hard X-ray range, two 0.9 T...
The presence of the electron cloud inside the chamber of high energy accelerators with positively charged circulating beams has been reported and studied by several facilities. Those studies intend to describe and predict which scenarios may present a mayor risk to operating the machine.
The electron cloud build-up inside the vacuum chambers might generate critical effects that diminish the...
This report details the mechanism design and heat load budget for a cryostat that replace liquid helium and liquid nitrogen with commercially available cold heads (cryocoolers). However, to ensure the proper functioning of cryogenic superconducting magnets with the limited cooling capacity of cryocoolers, careful management of heat transfer, insulation, cooling, electrical power, and vacuum...
Higher-Order Modes (HOMs) in superconducting radiofrequency (SRF) cavities are traditionally considered detrimental to efficient operation. They are often associated with beam instabilities and are actively damped. However, these “harmful” HOMs, if used strategically, can be transformed into a tool for providing extra control over the beam, which can introduce new opportunities that are not...
High-current and low-energy storage ring is an essential part of accelerator for industrial application. However, high intensity poses great challenge to beam stability through collective effects, which can be exacerbated at low energy. In this paper, we present a preliminary study on various collective effects in an application-oriented storage ring. The classical theory is reviewed, and...
The High Luminosity-Large Hadron Collider (HL-LHC) project at CERN aims to increase the integrated luminosity of the Large Hadron Collider by an order of magnitude compared to the LHC original design performance. To achieve this, the existing magnets surrounding the CMS and ATLAS experiments will be replaced with next-generation, high-performance superconducting magnets featuring larger...
BDSIM (Beam Delivery Simulation) is a Monte Carlo particle tracking tool for accelerator beamline modelling. It integrates particle transport with detailed geometry and physics using Geant4 for precise modelling of particle-matter interactions in 3D models of particle accelerators. Primarily for energy deposition studies and beam loss simulations, BDSIM allows a high degree of control and...
A collaboration is underway to investigate the impact of CSR and shielding on the beam of various shapes as it passes through a chicane. Experimental efforts are being made at the Argonne Wakefield Accelerator (AWA) facility. Currently, the facility is equipped with two identical doglegs with reversing quadrupoles that allow doglegs to function as a chicane, and manually adjustable shielding...
ALBA-II is progressing in the definition of an upgrade lattice that meets the requirements of the beamlines and perform well in terms of dynamics aperture and lifetime. The last changes were focused on further decreasing both the emittance (200 pm*rad) and the beta functions at the straight sections (around 2 m) for the improvement of the beamlines performances. The efforts to guarantee a good...
In the current and most evolved design concept of a muon collider, there exists two long (~1 km) channels for cooling newly created muons and anti-muons. Termed the `6D cooling channels', the beam is cooled in momentum and position space using a series of alternating polarity solenoids, which create an oscillating field in the beam direction, absorbers and radio-frequency cavities. In total...
FLUKA simulations of beamlines are important for un- derstanding numerous different aspects of accelerators, in- cluding beam losses, particle backgrounds, activation and shielding. Creating a beam-line simulation using FLUKA is a time consuming and potentially error prone process. This paper describes a set of python tools called pyflubl (Python FLUKA beam-line) which can create a FLUKA...
Quadrupole pumping is a longitudinal manipulation technique for bunch shortening, which works by modulating the RF voltage at twice the synchrotron frequency to excite bunch length oscillations. These controlled oscillations rotate the bunch in longitudinal phase space, with extraction set for when the bunch is shortest. Higher RF harmonics can also be used to linearise the synchrotron...
The National Synchrotron Radiation Research Center (NSRRC) has been at the forefront of advancing synchrotron radiation technologies, including the development of advanced magnet systems. We integrated a wiggler magnet utilizing 2G High Temperature Superconductor (HTS) tape into a cryogen-free system. The wiggler, an essential component for enhancing radiation output, operates effectively...
As part of its ongoing and future contributions to high-Q/high-G activities in major international projects such as PIP-II, ILC Technology Network, and the European Strategy for Particle Physics, INFN-LASA is upgrading its experimental facility for vertical cold tests of superconducting cavities. This upgrade will enable cavity performance characterization in a low residual magnetic field...
Irradiation-induced damage to undulators has become a critical problem in the operation of synchrotron radiation facilities and free-electron laser facilities. During the commissioning and light output phases of the Shanghai Soft X-ray Free Electron Laser facility, the performance of the radiation deteriorated. The main reason for this problem is the impact of high-energy particles on the...
Systematic research work including coating process optimization of Nb3Sn thin film on single cell cavity, quality control before and after coating Nb3Sn thin film on multi-cell cavity, and the construction and operation of LHe-free Nb3Sn SRF demo electron accelerator was carried out at IMP. The evolution of Nb3Sn thin films in the whole growth cycle was tracked by experiments, and the...
Accurate knowledge of wake functions is crucial in accelerator physics, serving as the cornerstone for understanding intra-bunch interactions and for controlling or mitigating instabilities that limit accelerator performance. Haissinski distributions, which describe the steady-state longitudinal bunch density, are intrinsically determined by the wake function experienced by the bunch. While...
The 7th International School on Beam Dynamics and Accelerator Technology (ISBA24) held in Chiangmai University during November 1-9, 2024, encompasses seven days opportunities where the foundation of accelerator physics is applied during hands-on sessions with simulation software including ASTRA, ELEGANT, Opera-3D and CST Studio Suite. Opera-3D, a finite element-based Maxwell’s equations...
The 7th International School on Beam dynamics and Accelerator technology (ISBA24) took place over nine days, from November 1 to 9, 2024 at Chiang Mai University in Thailand. The school, part of the KEK-IINAS-NX series, was jointly hosted by Chiang Mai University and the Synchrotron Light Research Institute (SLRI). Out of 115 applicants who had submitted resumes and recommendation letters, 64...
I show analytical expressions of the longitudinal and transverse impedances of a two-layered circular pipe and their practical expressions at high frequencies derived by using asymptotic expansions of the Bessel functions. These expressions are applied to resistive-wall impedance calculations of NEG-coated insertion-device(ID) pipes for the PF-HLS ring*, which is proposed as a 2.5/5.0 GeV...
The VEPP-2000 collider is a compact machine, which uses the round-beam concept to achieve high luminosity. Its compact size (24 m in circumference) limits the free space between the magnetic elements. Only 4 BPMs are installed in the ring with large phase advance between them (~2 pi). The key to improve its luminosity is to reduce the power of resonances. The implementing of the RDT...
The LHC is approaching the end of its third operational run, with machine protection and performance having demanded an excellent control of the single-particle dynamics. Additionally, the requirement to rapidly commission multiple diverse sets of optics configurations within each year and from year-to-year, placed clear demands on the measurement and correction methods employed. Tight...
The Quadrupole Resonator (QPR), originally developed at CERN, is a dedicated radio-frequency characterization equipment for evaluating superconducting material. It employs the calorimetric compensation technique and has a surface resistance resolution of less than 1 nOhm, operaing over a wide range of parameters, such as tem-peratures, resonant frequencies and magnetic fields. As a part of R&D...
The ASTERIX project, funded by CSN5 and proposed at INFN-LNF, aims to demonstrate a practical, meter-long X-band RF structure for linear accelerators made of hard copper and divided into four quadrants. The prototypes will be constructed by TIG welding. In the first year of the feasibility study, we will design the RF cavities for two full structures working at single-bunch and multi-bunch...
In this paper, we present the RF design of a mode-launcher integrated with an open-type, multi-cell 12 GHz 4-sector structure. The electromagnetic design is carried out using the 3D full-wave electromagnetic solver CST-Microwave Studio. To ensure compactness, a key focus of the integration process is the minimization of the distance between the coupler cell and the accelerating open structure....
The RF window acts as a barrier between the vacuum and air, gas, or water while allowing RF power to pass through with minimal loss. Resonant modes (called "ghost modes") can occur within the ceramic disk of a window. The frequencies of these modes depend on the material and size of the ceramic. Ceramic disk dimensions must be carefully optimized to minimize reflections and avoid ghost mode...
The Electron-Ion Collider at BNL requires several crabbing systems that will be operating at 197 MHz and 394 MHz to compensate for the loss of luminosity due to the large crossing angle of the colliding beams. Two 197 MHz crab cavity cryomodules containing two cavities each will be installed in the Hadron Storage Ring (HSR) at the IP6 interaction region. Due to its large size compared to...
Coherent electron cooling plays an important role in the Electron Ion Collider (EIC) by providing a fast cooling rate at collision energy to counter the emittance growth driven by intrabeam scattering effects. In this paper, we report on the high-fidelity simulation of the electron beam transport through the amplification section of the cooling channel. We will show the amplification of the...
A novel storage ring is proposed in which the bunch maintains a fixed orientation relative to the outside world (does not rotate with the ring as usual). In this geometry, magnetic focussing can confine all three dimensions of the bunch without RF. The application of this ring to ultra-low emittance Coulomb crystals is investigated, where the focussing force balances the space charge to give...
Capability for generating an attosecond bunch can provide interesting opportunities to wakefield accelerator research. We have been studying requirements and challenges in beam dynamics to produce an attosecond bunch using an existing beamline at Argonne Wakefield Accelerator (AWA) facility. One unavoidable limitation of this study is that conventional C-typed chicane is not available. Thus, a...
In the SuperKEKB electron-positron collider, the coupled-bunch instability caused by the accelerating mode of RF cavities becomes severe in high beam current. To suppress it, the ARES cavities have been used. The accelerating cavity is coupled with an energy storage cavity via a coupling cavity between them. While the beam is accelerated by the π/2 mode, the parasitic 0 and π modes are damped...
The compact STorage ring for Accelerator Research and Technology (cSTART) project at the Karlsruhe Institute of Technology (KIT, Germany) aims to explore non-equilibrium electron beam dynamics and injection of laser-plasma accelerator (LPA) bunches. The Very Large Acceptance compact Storage Ring (VLA-cSR) is also filled by a second injector that delivers ultra-short bunches from the...
In ultrafast electron diffraction experiments, the scattering cross-section, q-range, and space-charge effects are critically influenced by the electron beam energy, which is constrained by the high-voltage breakdown. By integrating a 100 kV DC electron gun with a 3 GHz radiofrequency cavity powered with a 400 W amplifier, we demonstrate a net energy gain of up to 31 keV. Here we present...
The GALACTIC Vlasov solver can be used to study the impedance-induced transverse coherent instabilities, considering any longitudinal distribution function, describing the beam with transverse coherent oscillation modes in the frequency domain and ending up with an eigenvalue system to solve. In this paper, the effect of the transverse coherent direct space charge is added, considering a...
A five-year project (MEXT advanced Accelerator element Technology Development (MEXT-ATD)) funded by the Ministry of Education, Culture, Sports, Science and Technology (MEXT) began at KEK in FY2023. The goal is to manufacture and construct a cryomodule (CM) that satisfies the ILC (International Linear Collider Project) specifications and conduct cooling tests. The 3D model of the cryomodule...
PAL-XFEL is planning to install second hard X-ray undulator line (HX2) to meet the high beamtime demand from the users. The photon energy range for the second hard X-ray beam line is from 2~ to 11 keV which is lower than the first hard X-ray photon energy range (2 ~ 20 keV). The required undulator parameters are 35 mm period, max Keff=3.48 at 9.00 mm gap, ~ 3.0 m magnetic length with phase...
Since the completion of Taiwan Photon Source (TPS) commissioning in 2015, we have developed and constructed nine APPLE-II undulators of various designs to provide users with soft X-ray sources, particularly for circularly polarized light. To optimize the use of straight-section space, the lengths of the APPLE undulators range from 4.4 to 0.8 meters to accommodate installation constraints....
STFC is responsible for delivering 20 high-beta 650 MHz cavities for the PIP-II project, with industry partners now producing series cavities. Both pre-series cavities have set world records in performance and cleanliness, meeting the project’s stringent requirement for field emission-free operation, accelerating gradient, and Quality factor. Achieving this milestone required an...
With a change in the LHC machine optics foreseen for 2025 and the possible reduction of beta-star, optics commissioning will become even more of a challenge for the CERN Optics Measurement and Correction (OMC) team. In particular, the increased sensitivity of the optics to non-linear imperfections, requiring a plethora of accurate measurements, is expected to be a time consuming task. In...
The superconducting cyclotron SC240 is used to accelerate proton beams to 240 MeV for proton therapy. The SC240 is an isochronous 4 sectors compact cyclotron with a central magnetic field of 2.5 T. Particles acceleration is performed under the second harmonic mode of the radio-frequency (RF) system, consisting of two independent cavities located in the cyclotron valleys. Block on the chimney...
The FCC-ee booster injection kicker, will be injecting 4 particles bunches per single kick. The bunch separation in the booster ring is 25 ns and therefore requiring a faster kicker rise and fall time to not perturb injected or already circulating bunches. The wakefield impedance of the stripline is also important to not perturb the stored beam as well as it is necessary to ensure a good...
Space charge effects in combination with betatron resonances limit the performance of high-brightness LHC beams in the CERN Super Proton Synchrotron (SPS). Here we report on experimental studies performed with single-bunch proton beams, monitoring transverse emittance evolution and particle losses while performing tune scans across the horizontal and vertical planes. Two significant resonances...
SIRIUS, the Brazilian 4th-generation synchrotron light source, operates in top-up mode at a current of 200 mA. Despite previous optimizations, the storage ring injection system still requires improvements in efficiency, to attend the tight demands in terms of repeatability and charge per pulse. In this context, this work investigates the large residual horizontal orbit distortion in the...
Recently proposed transverse wiggler is an intriguing tool for imparting designed correlations in phase space. While several simulations have demonstrated its feasibility, the method using the transverse wiggler has several concerns need to be addressed. Beam evolution along the wiggler can introduce errors in the designed correlation. Wiggler fields have strong vertical position dependence,...
Over the past two decades, very high-energy electron (VHEE) beams ranging from 50 to 250 MeV have been explored as a potential technology for treating deep-seated tumors. FLASH radiation therapy (FLASH-RT) delivers ultra-high dose rates (UHDR) within a few milliseconds, suggests the possibility of enhanced cancer cell lethality while reducing damage to normal tissues. Combining VHEE with...
The cERL injector objective is to produce and deliver a high-quality electron beam to the recirculation loop. However, a recent observation of an anomalous "triangle beam" profile just after the first solenoid presents significant challenges. This distorted beam profile can lead to inaccurate parameter measurements, reduced focusing and collimation efficiency, and increased sensitivity to...
In the 3-GeV Rapid Cycling Synchrotron (RCS) of the Japan Proton Accelerator Research Complex (J-PARC), the beam power ramp-up aiming to surpass the design of 1 MW enhances the space charge effect. It pushes the beam toward the structure resonance. To mitigate the beam loss, the operating point is required to be apart from the structure resonance as the beam power ramp-up. However, large beam...
A 162.5 MHz, optimal beta = 0.19 pure niobium half-wave resonator (HWR) called HWR019 for the superconducting driver linac of the China initiative Accelerator-Driven subcritical System (CiADS) has been designed and analyzed at the Institute of Modern Physics, Chinese Academy of Sciences (IMP, CAS). The linac requires 24 HWR019s to accelerate protons from 6.8 MeV to 45 MeV. This paper mainly...
After the great success of KEKB asymmetric-energy collider achieving the world highest luminosity, the ambitious upgrade SuperKEKB collider aims to take the positron-electron colliders to the next level by achieving 40 times higher luminosities. However, this represents a huge challenge, requiring of a highly precise way to control the beams to suppress emittance growth and to assure their...
NSRL recently proposed a future plan to further upgrade the HLS to an EUV diffraction-limited storage ring, named HLS-III. In this paper, a symmetric double-double bend lattice with long and mid-straight sections is studied as a highly promising design for the HLS-III storage ring. The design achieves an ultra-low natural emittance of 2.82 nm·rad at 800 MeV, while maintaining the current eight...
Recently, KEK PF has started developing a superconducting multipole wiggler (SC-MPW) for an application in next-generation light source ring. The SC-MPW is expected to be a key insertion device for the light utilization of a wide wavelength region by aiming at high-brightness and high-energy X-ray production while keeping the stored beam energy as low as 2.5 GeV. In addition, the short period...
Accelerator kicker magnets, which commonly use ferrite and other insulating materials, can encounter High Voltage (HV) performance limitations due to interactions with the particle beam. These interactions, can lead to electron cloud buildup and charging phenomena on exposed surfaces, negatively impacting kicker performance, particularly at high beam intensities. To mitigate these effects,...
A single-aperture two-layer Canted-Cosine-Theta (CCT) sextupole magnet using as conductor high-temperature superconducting (HTS) ReBCO tape has been developed for the short straight sections (SSS) of the FCC-ee study. Manufacturing details, including paraffin wax impregnation and cryogenic temperature measurements, are presented. This demonstrator represents the first CCT magnet constructed...
NSRRC builds four home-made solid state power amplifier towers to provide 300 kW for one superconducting RF cavity at TPS. The power combining tree of one tower is two-stages structure with a complex wire connection. In order to simplify the wire connection and increase the power combining efficiency, we devote resources to develop the cavity combiner. In this study, a 21-ports cavity combiner...
This study investigates the influence of insertion devices (IDs) on the optical properties of the Solaris electron storage ring through a combination of experimental measurements and simulations. The effects of various ID settings were analyzed using tune measurements and the Linear Optics from Closed Orbits (LOCO) method. These results were compared with simulations performed using the Python...
The design of the ALBA upgrade forsees the use of an active harmonic cavity system for bunch lengthening. The resulting RF-potential will be a combination of a harmonic and a quartic potential. The corresponding stability diagram will be computed and compared to the stability diagram based on a pure quartic RF-potential. It will be checked if an already existing HOM in the DAMPY cavities and a...
The eddy current type septum magnets (Eddy-septa) are used for fast extraction in J-PARC MR from 2022. Currently, the operation of the Eddy-septa is very stable. However, we have some still technical issue. One is an output pulsed current measurement by current transfers. The peak value of the output pulsed current is measured pulse by pulse and the measured value is used for a feedback system...
The Electron-Ion Collider (EIC) is being designed by BNL in collaboration with Jefferson Lab. The Phase-I design includes the installation of two cryomodules of 197 MHz crabbing cavities installed at the Hadron Storage Ring (HSR) at the interaction region, IP6 that has a crossing angle of 25 mrad. Each cryomodule consists of two 197 MHz RFD type crabbing cavities. The first article cavity has...
In the Japan Proton Accelerator Research Complex (J-PARC) Main Ring (MR), to address the issue of resonance correction for third-order resonances in both on- and off-momentum particles, an upgrade project utilizing 24 Trim-S units has been proposed based on numerical simulations. As a first step in verifying its effectiveness, four additional Trim-S (new Trim-S) power supplies, configured with...
Multi-bunch instabilities, often driven by narrowband impedance sources such as higher-order modes, present significant intensity limitations in synchrotrons. One approach to mitigate these instabilities is applying a double harmonic radio frequency (RF) system, which can increase the intensity threshold by enlarging the synchrotron frequency spread. In this study, intensity thresholds are...
Super Charm Tau factory is a proposed electron-positron double ring collider with crab waist collision scheme operating in wide beam energy range from 1.5 GeV to 3.5 GeV with peak luminosity of 10^35 cm^(-2) s^(-1). The polarized electron source and three Siberian Snakes provide 80% longitudinally polarized electron beam at 2 GeV. Superconducting wigglers decrease damping times, effects of...
The collective effects observed in storage rings with high-intensity beams are numerous and diverse. One such effect is that of periodic beam loading of accelerating RF cavities. This effect is contingent upon the impedance of the fundamental mode of the RF cavities and the mode of filling pattern. In a multitude of configurations, the periodic beam loading effect in storage rings leads to a...
The results of Run 24 experiments at Relativistic Heavy Ion Collider (RHIC) for improving luminosity using optics tuning are presented in this study. In the first experiment, MADx matching was used to output magnet strengths corresponding to specific s star movements around Interaction Region 8 (IR8). The corresponding Zero Degree Calorimeter (ZDC) signal was measured in place of luminosity,...
In the CERN Super Proton Synchrotron (SPS), a new AC dipole excitation functionality has been implemented with the aid of the Beam-Based Feedback and Diagnostic Systems. This feature facilitates precise and systematic optics measurements, presenting a robust alternative to the conventional single-kick excitation method. Comparative studies of AC dipole and single-kick excitations have been...
A three-dimensional spiral beam injection scheme* has been developed to realize very precise measurement of the muon spin precession frequency in the level of sub-ppm. A 300MeV/c muon beam is injected into a precisely adjusted storage magnet of sub-ppm uniformity by applying medical MRI magnet technologies for J-PARC muon g-2/EDM experiment. A strongly X-Y coupled beam is required to deliver...
Ongoing conceptual studies for a 10TeV muon collider identified rapid cycling synchrotrons as major engineering challenge. Due to the muon’s short lifetime of only 2.2µs at rest, normal-conducting bending magnets with field rise rates of well beyond 1kT/s are indispensable to support accordingly fast acceleration cycles. Energies of 100MJ will be interchanged between magnets and capacitor...
The Taiwan Photon Source (TPS) of the National Synchrotron Radiation Research Center (NSRRC) in Taiwan has integrated Solid-State Power Amplifiers (SSPAs) into routine operations since 2023, supporting a stored beam current of 500 mA. In response to the phasing out of Ampleon's BLF578 and the growing demand for improved energy efficiency, a new SSPA was developed based on the existing module...
The proton driver of a future Muon Collider complex is designed to deliver a multi-GeV, short and high-intensity proton bunch to a target in order to maximize the muon yield. In the International Muon Collider Collaboration (IMCC), two high power H- Linac configurations are studied: a 2 MW with a beam energy of 5 GeV, and a 4 MW with a beam energy of 10 GeV. The Linac is followed by an...
Collective effects can have a strong influence on the beam stability and performance in synchrotron light sources. Landau cavities or RF harmonic cavities are a tool that is employed at 4th generation storage ring light sources to reduce the impact of or even prevent instabilities arising from collective effects. The positive effect of Landau cavities is based on the lengthening of the...
Superconducting cavities are indispensable elements in modern particle accelerators, utilizing the ultra-low sur-face resistance of superconductors to achieve exceptionally high quality factors. In this work, we apply the least action principle to derive an equivalent RLC circuit model, offering a unified theoretical framework to describe the electromagnetic behavior of superconducting...
We present updated simulation results on the maximum brightness achievable by a 1.6-cell cold copper C-band photoinjector, designed for testing and commissioning as part of the Cathodes and RF in Extremes project at Los Alamos National Laboratory. Previous simulations highlighted the high brightness attainable with a 250 pC bunch charge, attributed to the high accelerating gradients and the...
This work presents the results of single-bunch-instability measurements in the Diamond storage ring. A streak camera was used to measure the bunch lengthening with current, whilst transverse multi-bunch feedback (TMBF) was utilised to quantify the charge-dependent betatron tune shifts and the head-tail instability thresholds. The results show that increasing chromaticity can be used to...
The design and operation of modern accelerators demand advanced simulation tools capable of addressing complex challenges. Differentiable simulations are particularly valuable, as they enable gradient-based optimization techniques that significantly reduce computational costs and efficiently tackle high-dimensional problems. The PyTorch-based simulation code Cheetah was developed to combine...
The radio-frequency quadrupole test stand (RFQ-TS) was prepared for conditioning the spare RFQ in the J-PARC Linac. Additionally, the RFQ-TS is used for the development of accelerator components and the acquisition of beam parameters. The digital feedback system of the Low-Level RF (LLRF) in the RFQ-TS was previously using the discontinued cPCI system, which had been in use for 20 years since...
The European Synchrotron Radiation Facility (ESRF) has built and characterized many insertion devices and magnets over the past decades. The magnetic measurements rely on dedicated benches, based on stretched wire for integral measurements and on hall probes for local measurements. A major upgrade of these benches is being developed. It includes new features such as coordinate measurents,...
LC resonant circuit is widely used in all kinds of pulse power supply because of its simple structure and reliable performance. Among them, the scheme with thyratron as the main power device has been verified for a long time in the BEPCII injection system. With the continuous improvement of the technical requirements of all kinds of accelerators, the performance of the pulser has become...
The goal of the ASTERIX project, proposed at INFN-LNF and funded by the CSN5, is the first-time demonstration of a practical, meter-long X-band RF structure for real linear accelerators made of hard copper and four quadrants. Our joining technique will be the TIG welding for the prototype. During the feasibility study, in the first year, we will proceed to the RF cavity design of two full...
In order to achieve the necessary bunch charge, the Rapid Cycling Synchrotron utilizes bunch merging. The altered longitudinal motion during merges has the potential to reduce dynamic aperture and cause emittance growth. Tools for analyzing the effects of merging have been developed for the AGS using Bmad and a simplified tracking code in Julia. These tools are applied to the merges of the...
Nonlinear effects in particle accelerators have historically been treated as harmful influences that necessitate various mitigation schemes. Therefore, the simulation tools available are largely focused on identifying and correcting resonances. However, recent advances proved that nonlinear beam dynamics enables new techniques for manipulating particle beams and can characterise diffusion and...
