The Ion Beam Centre at Kurukshetra University is the first facility established by Department of Science and Technology, Govt. of India by funding and supporting Accelerator based research programs in university system. The facility has been providing accelerator-based research facilities to researchers of host university as well as researchers from all over India. The air insulated high...
A Structured Laser Beam (SLB) is a type of optical beam with spatially inhomogeneous 3D polarisation structures. Generating SLBs from vector beams allows the creation of Hollow Structured Laser Beams (HSLB) with a dark central core. In this way, atypical electric and magnetic field vectors, which are purely longitudinally polarized in the dark zones of the beam, are obtained. The SLB spatial...
A 1–2 GHz stochastic cooling system is being de-veloped to provide fast 3D cooling of hot secondary beams (antiprotons at 3 GeV and rare isotope ions at 740 MeV/u) at intensities up to 10^8 particles per cycle. For antiproton cooling, cryogenic plunging pick-up electrodes will be used to improve the ratio of Schott-ky signals to thermal noise. To cool hot rare isotope beams quickly, a...
The FLASH2020+ project will open up new excellent opportunities for science on the highest level. The FLASH facility will not only produce soft x-ray SASE photon beams at full MHz repetition rate in a burst mode in FLASH2, but will also provide in FLASH1 several thousand fully coherent pulses per second using the HGHG and EEHG external seeding schemes. New types of experiments are enabled by...
In order to promote the studies of low emittance RF photo cathode and high gradient accelerating structures, a C-band test platform has been initialized since late 2021. In this paper, an overview of the present status and future plans of this platform is given, including a 3.6-cell C-band RF photo cathode and a C-band RF traveling-wave accelerating structure. In addition, other on-going...
Terahertz (THz) radiation sources are increasingly significant for many scientific frontiers, while the generation of THz radiation with high-power at wide-tunable frequencies is still a limitation for most existing methods. In this paper, a compact accelerator-based light source is proposed to produce coherent THz radiation with high pulse energy and tunable frequency from 0.1 THz to 60 THz....
Purpose: In the effort to develop a compact dielectric wall accelerator (DWA) system for proton radiotherapy, this work aims to demonstrate the feasibility of a drift step recovery diode (DSRD) based pulse forming network (PFN) to generate high magnitude, nanosecond scale voltage pulses at high repetition rates.
Methods: An initial numerical feasibility study was conducted in order to...
The magnetic and mechanical designs of a force-neutral adjustable phase undulator (FNAPU) are pre-sented. The FNAPU combines two magnetic assemblies with equal periods, one with an undulator magnetic structure and one with a force compensation magnet structure. The latter is used to neutralize the magnetic force affecting the undulator magnetic structure and vice versa in all undulator phases....
A High Brightness Beams Test Facility has been recently funded at the INFN-LASA laboratory in Segrate (Milan- Italy). The Test Facility will allow to perform developments in ERL construction and design and to carry out experiments with the high current CW electron beam in frontier areas of accelerator physics. The Test Facility setup will comprise a high-performance laser driven DC Gun...
In this paper we report on the status and performance of a newly commissioned high brightness electron beamline at Tsinghua University. The beamline is dedicated to research on the physics and technologies of multi-MeV, low charge, high brightness electron beams, as well as applications including MeV ultrafast electron diffraction and imaging. The layout, simulation and measurement results of...
J-PARC has three accelerators, 400MeV linear accelerator (LINAC), 3GeV rapid cycling synchrotron (RCS), and 50GeV (currently 30GeV) main ring (MR), which are connected by beam transport lines. The proton beam is delivered from the RCS to muon and neutron targets in the materials and life science experimental facility (MLF) via a beam transport line called 3NBT. A pulsed bending magnet in the...
Angular dispersion-induced microbunching (ADM) scheme was proposed to generate high harmonic coherent radiation in the storage ring with weak energy modulation amplitude. However, it is still difficult to convert the external UV seed laser into the sub-nanometer wavelength. In this paper, we proposed a novel scheme based on ADM mechanism. By properly choosing the parameters, theory and one...
Regarding high current e+ sources, the almost universal usage of target-based production schemes combined with conventional capture technology has led to poor transmission efficiencies. This long-standing difficulty to handle the extreme e+ transverse emittance and energy spread has been a major impediment for future, high luminosity lepton collider designs. The PSI Positron Production...
X-ray free electron lasers, especially fully coherent femtosecond free-electron laser (FEL) pulses, are widely used in numerous fields. This study aims to propose a new principle for generating fully coherent femtosecond X-ray pulse based on the Shanghai soft X-ray Free Electron Laser User Facility (SXFEL-UF). The principle was based on fresh-slice technique. First of all, the electron beam...
Muons have been playing an important and unique role in both fundamental physics and applied sciences; Recent results of the muon magnetic anomaly hint at physics beyond the Standard Model; Muon spin rotation techniques have been widely applied to the study of superconductivity and magnetic materials. A typical muon experiment measurement time of 10 muon lifetimes means that an ideal muon...
In order for the new ATLAS Materials Irradiation Station (AMIS) to take advantage of the future multi-user capabilities at ATLAS, a pulsed kicker is needed to switch 1 MeV/u heavy-ion beams. At this energy and due to space limitations, a pulsed electric kicker is very challenging due to very high voltage requirement, and a magnetic kicker is also very challenging due to the high magnetic field...
The China Spallation Neutron Source (CSNS) is a large scientific facility for frontier research by using the medium energy protons bombardment of tungsten target to produce a large number of scattered neutrons. The rapid cycling synchrotron (RCS) adopts the single-turn fast extraction scheme to extract the proton beam with the energy of 1.6GeV, and the extraction repetition frequency is 25Hz....
The CERN Linear Electron Accelerator for Research (CLEAR) has been operating since 2017 as a user facility providing beams for various experiments. We created a start-to-end model of the CLEAR setup in RF-Track, aiming to optimise the CLEAR accelerator as a driver for an X-ray source based on inverse-Compton scattering. RF-Track, a CERN-developed particle tracking code, can simulate the...
In a subcritical assembly, heavy metals are used to generate additional photo-neutrons using high-energy electrons. One of the options for a neutron-generating target is a set of tungsten plates coated with tantalum. It is promising due to the high neutron yield upon irradiation with high-energy electrons.
The operating conditions of a tungsten target exposed to electron beams with an energy...
High gradient radio-frequency structures are of considerable interest in ongoing structure wakefield acceleration research. The prospect of economical accelerators with a small footprint in the sub-terahertz regime shows promise in achieving high gradient and high efficiency, and in that vein, we present a design for a metallic corrugated waveguide designed at 110 GHz. This W-band structure...
The Facility for Rare Isotope Beams (FRIB), a major nuclear physics facility for research with fast, stopped, and reaccelerated rare isotope beams, started operation in May 2022. Since then, five nuclear physics experiments have been successfully accomplished. The experiments with rare isotope beams typically last within 1-2 weeks. Each experiment requires a different primary beam and its...
The superconducting radio-frequency photoelectron injector (SRF photoinjector), now under commissioning at the SEALab accelerator test facility, has the potential to cover a fast area of beam parameters. Electron bunches from fs to ps length, with fC to nC charge can be accelerated to a couple of MeV beam energy. The legacy from the energy-recovery linac (ERL) test facility bERLinPro, the...
The spectro-temporal characteristics of free-electron laser (FEL) radiation emerging from external seeding schemes such as high-gain harmonic generation are shaped by the properties of the initial seed laser. Accurate control of the seed laser envelope and phase is essential to allow for precise manipulation of the FEL output. Based on experimental data obtained at the seeded FEL user facility...
Beam-driven plasma-wakefield acceleration has the potential to reduce the size and construction cost of large-scale accelerator facilities, by providing accelerating fields orders of magnitude greater than that of conventional accelerating structures. To keep the running costs affordable, high energy-transfer efficiency from the wall-plug to the accelerated bunch has to be demonstrated. For...
To complete the Italian In-Kind contribution to the ESS SRF Linac, we are working on the qualification of the last eight missing cavities. To achieve this, we are proceeding with reprocessing of not yet qualified cavities and, as a mitigation, we are constructing at the vendor four more cavities. In this paper, we report on the actual status of both of these activities with the most recent results.
Adiabatic capture of a coasting beam can be used to minimise the emittance of the resulting bunched beam – for example to capture the injected beam at the start of the acceleration cycle. In some cases, the voltage follows the so-called iso-adiabatic voltage law in order maintain the same adiabaticity throughout capture. Here we show that a linear evolution can result in a smaller final...
The design and construction of continuous wave (cw) superconducting (sc) high intensity linacs is a crucial goal of worldwide accelerator technology development. The standalone sc cw heavy ion HElmholtz LInear ACcelerator (HELIAC) is a common project of GSI Helmholtz Centre for Heavy Ion Research and Helmholtz Institute Mainz (HIM) under key support of Goethe University Frankfurt (IAP). In...
The Advanced Ion Source for Hadrontherapy (AISHa) is an ECR ion source operating at 18 GHz, developed with the aim to produce multiply charged ion beams with low ripple, high stability and reproducibility, low maintenance. Due to its unique peculiarity, it is a suitable choice for medical applications, but also to nuclear-physics and material experiments.
Two AISHa sources have been realized...
The high Quantum Efficiency (QE) and low Mean Transverse Energy (MTE) of alkali antimonide photocathodes enable the production of bright electron beams for a variety of accelerator applications. Growing alkali antimonide photocathodes requires an elaborate growth chamber and an operator with considerable expertise. Moreover, their sensitivity to chemical poisoning requires storage in an...
A first beam dynamics and RF design of an Alvarez-type drift tube linac (DTL) has been defined in the framework of the EU project, HITRIplus. Its main application is to be exploited as a carbon (12C4+) and helium (4He2+) ion injector into a compact synchrotron for patient treatment. As a second implementation, helium particle acceleration with a higher duty cycle of 10% enables the possibility...
We describe active Q-switched X-ray regenerative amplifier FEL scheme to produce fully-coherent, high-brightness hard X-rays. In this scheme, a moderate energy chirp is introduced to the electron beams to shift the Free Electron Laser (FEL) radiation frequency outside the reflectivity bandwidth of the Bragg crystal. By actively controlling the chirp of the electron beam, the ratio of the...
A new type of accelerator called Harmonytron has been proposed. The Harmonytron is based on a scheme of vertical Fixed-Field Alternating gradient (vFFA) focusing with harmonic number jump beam acceleration. An electron model of vFFA accelerator is under development at Kyushu University. The current status of the vFFA accelerator will be discussed.
Energy matching between two hadron synchrotrons is the adjustment of the magnetic bending fields and beam momentum to obtain a correct transfer between the two. Conventionally, energy matching is achieved by turning off the RF system and measuring the revolution frequency of the de-bunching beam in the receiving accelerator. For an ideal circumference ratio, the orbits would then be centred in...
In October 2022, the UK XFEL project entered a new phase to explore how best to deliver the advanced XFEL capabilities identified in the project's Science Case. This phase includes developing a conceptual design for a unique new machine to fulfil the required capabilities and more. It also examines the possibility of investment opportunities at existing XFELs to deliver the same aims, and a...
The synchrotron SIS18 at GSI uses resonant extraction for slow beam extraction. Recently it was discovered that about 50% of the anode wires of the electrostatic extraction septum were broken during beam operation. In this paper, we present the analysis of the possible loss scenario that led to the anode wire damage and suggest machine protection measures to prevent future damage. The...
The self-seeded free-electron laser (FEL) is developing towards advanced FEL modes such as ultra-short pulse, multi-color and high intensity, and the influence of thermal loading instantaneously loaded on monochromatic elements will not be ignored. Therefore, it is necessary to quantitatively describe the changes in X-ray optical properties of crystals caused by transient thermal loading...
The ESS cavity operation is challenging due to long RF pulse, high gradient, high beam power and high demands for energy efficiency and availability. These require a better understanding of RF-cavity dynamics and insight into RF-cavity interaction. RF and cavity dynamics identification relies heavily on high precision measuring and characterizing basic cavity parameters (Ql, dynamic detuning,...
The development of high-power, attosecond methods at free-electron lasers has led to new possibilities in the probing and control of valence electron dynamics. Beyond simple observation of ultrafast processes, one of the longstanding goals of atomic physics is control of the electronic wavefunction on attosecond timescales. We present a scheme to generate sub-femtosecond pulse pairs from x-ray...
AWAKE is the first proof-of-concept proton-driven plasma wakefield acceleration experiment. AWAKE’s first phase concluded in 2018, with controlled acceleration of electrons to energies of 2 GeV in a 10-m long plasma cell. AWAKE’s second phase operates since 2021. It has been divided into four stages (Run 2a, Run 2b, Run 2c and Run 2d) to prove step by step good that the required electron beam...
High-energy proton bunches offer the potential to drive wakefields over very long distances in plasma. An externally-injected electron bunch can thus in principle experience very large energy gain (hundreds of GeVs to TeVs) in a single plasma with GeV/m accelerating gradient. AWAKE explores this potential with 400GeV proton bunches from the CERN SPS. Based on the succesful demonstration of...
A cavity based free-electron laser (CBXFEL) is a next generation X-ray source promising radiation with full three-dimensional coherence, nearly constant pulse to pulse stability and more than an order of magnitude higher spectral flux compared to SASE FELs. In this contribution, an R&D project for installation of a CBXFEL demonstrator experiment at the European XFEL facility is conceptually...
X-ray beams with orbital angular momentum (OAM) have emerged as a powerful tool for investigating matter. Traditional optical elements, such as spiral phase plates and zone plates, have been employed to generate OAM light. However, applying these elements in x-ray free-electron lasers (XFELs) remains challenging due to high impinging intensities and efficiency concerns. The self-seeded FEL...
ARES is an electron linear accelerator at the SINBAD facility at DESY. It aims to deliver reliable high-brightness beams with energy in the range of 100 to 150 MeV having fs to sub-fs bunch lengths. This is ideal for injection into novel high-gradient acceleration devices such as dielectric laser accelerators and laser-plasma accelerators which feature fields with fs to ps period. The ARES...
The High Energy Photon Source (HEPS) is a synchrotron radiation source of ultrahigh brightness being built in China. Its accelerator complex is composed of a 6-GeV storage ring, a full energy booster, a 500-MeV Linac, and three transfer lines. The Linac is an S-band normal conducting electron linear accelerator with available bunch charge from 0.5 nC up to about 10 nC. The Linac installation...
For the high power spallation neutron sources,
RUEDI is a proposed relativistic ultrafast electron diffraction and imaging facility for the UK. It will deliver single-shot time-resolved imaging with MeV electrons, as well as ultrafast electron diffraction at 10 fs timescales. The few-MeV-scale imaging and microscopy line aims to deliver high charge (up to 108 electrons), ultra-low emittance electron bunches to a 10µm sample with...
RUEDI is a proposed relativistic ultrafast electron diffraction and imaging facility. It will have two beamlines: a diffraction beamline and an imaging beamline. This proceeding discusses the beam dynamics design of the diffraction beamline. The diffraction beamline needs to have the best temporal resolution possible which requires short bunch length and minimal time of arrival jitter at the...
In the framework of a collaboration between Sapienza University of Rome, the Italian Institute for Nuclear Research (INFN) and the Curie Institute, the proposal of a new facility dedicated to the Very High Electron Energy (VHEE) FLASH irradiation is in progress. The aim is to exploit the promising VHEE regime for the translation of electron FLASH radiotherapy into clinical practice in order to...
A beam dynamics optimization study of an electron injector linear accelerator including an RF photoinjector gun was performed using MOGA (Multi-Objective Genetic Algorithm). To meet the requirements of electron beam characteristics at the linac end, the optimization goal was to minimize transverse beam emittance and energy spread. The transverse and longitudinal beam sizes were constrained to...
Neutrons are an essential tool for studying the structure and dynamics of matter. The High Brilliance neutron Source (HBS) project aims to develop a scalable Compact Accelerator-driven Neutron Source that will enable neutron fluxes at the corresponding instruments comparable to existing fission-based or spallation neutron sources. The full-scale HBS facility is characterized by the...
Beam intensities and powers being increasingly strong, installations increasingly large, the need to reduce losses and costs (i.e. dimensions) becomes essential. Improvements are possible by increasing the acceptance in the two transverse planes. For example for LEBT lines and radioactive beams, a large geometric acceptance allows efficient transport of reaction products that have large phase...
The injectors for the LHC at CERN underwent a major upgrade during a recent two-year long shutdown in the framework of the LHC Injectors Upgrade (LIU) project. Following this upgrade, the Proton Synchrotron (PS) was restarted in 2021, with the same beam quality as before the upgrade quickly achieved or surpassed. This contribution details the current beam performance for fixed-target and...
The ALBA and BESSY II Linacs consist of a thermionic Pierce-type electron gun that delivers e- at 90 keV in pulses of 1 ns with a maximum charge of 0.25 nC/bunch. The gun is followed by a set of standing wave bunching cavities and traveling wave accelerating structures to further increase the beam energy, up to 50 MeV at BESSY II and up to 100 MeV at ALBA, while keeping the energy spread below...
The RAON accelerator has been constructed for various fields of science programs since 2011. The installation of the low-energy superconducting accelerator section (SCL3) had finished at the end of 2021, and the cooling of the cryogenics system started in early 2022. Prior to the SCL3, the beam commissioning has been carried out at the injector section of the RAON accelerator since 2020, and...
The new generation BNCT facilities require the management of high intensity proton beams (tens of mA). As a matter of fact, the total beam power can easily overcome hundreds of kW. Consequently, it is not only important to keep under control the losses but also to manipulate the beam distribution to decrease the power deposited along the accelerator and on the target. In this paper we will...
Plasma wakefields can produce broadband electron spectrums that can mirror the characteristics of the electron fluxes that exist in the planetary radiation belts. The SAMURAI RF facility which is currently being constructed and commissioned at UCLA, will be capable of producing beams with 100s pC of charge with bunch lengths in the 100s of fs range with low transverse emittances in the 3-80...
HPSim, the GPU-powered multi-particle simulation code developed for LANSCE, can provide critical 6-D beam distributions in near real-time to LANSCE user facilities. We will present the benchmarking results for HPSim to the LANSCE linac and our effort to provide a real-time distribution to the Isotope Production Facility.
Resonant slow extraction is a beam extraction method which provides a continuous spill over a longer duration than can be achieved with fast single-turn or non-resonant multi-turn extraction. By using transverse excitation to drive the circulating particles onto the resonance, a beam can be delivered to stationary target experiments which require low intensity, long-duration beams.
In order...
We present the conceptual design of a compact light source named BriXSinO. BriXSinO was born as a demonstrator of the Marix project, but contains also a dual high flux radiation source Inverse Compton Source (ICS) of X-ray and a Free-Electron Laser Oscillator of THz spectral range radiation conceived for medica applications and general applied research. The accelerator is a push-pull CW-SC...
In the first prototype of the AXSIS light source, electrons sourced from a 55 keV DC gun are first compressed by a THz-powered buncher, then accelerated in a THz-driven “booster” to 430 keV kinetic energy and finally accelerated to 20 MeV in a THz-powered LINAC. Guided by simulations, a booster prototype was developed employing three layer segmented structures and requires 400-µJ single-cycle...
The HL-LHC project covers the upgrade of the LHC, aiming at collecting an integrated luminosity of 3000 fb-1 equal to a 10-fold increase of the nominal LHC performance. Approved in 2016 for a 950 MCHF budget, the project is shaped by 19 work-packages, covering all expertise areas, from beam dynamics to technical infrastructures. A truly international effort is deployed, where 38 institutes...
The PolFEL free electron laser project comprises 185 MeV cw-linac furnished with ASG electron gun and 4 Rossendorf-like cryomodules. The beam diagnostics system, besides bringing the beam to undulators, inverse Compton scattering interaction point, and finally to the dump, system is dedicated to metallic superconducting photocathodes development, in particular to gun performance...
We present our 1.6-cell radiofrequency cavity design for a photoinjector under development for producing intense electron bunches with 250-pC beam charge and normalized emittance below 100 nm rad for cryogenic temperature operation. The cavity cell profile was designed by SLAC and UCLA, optimized for maximal shunt impedance and minimal peak magnitude of the electric and magnetic field. The...
Laser-wake field accelerators (LWFAs) are potential candidates to produce intense relativistic electron beams to drive compact free electron lasers (FELs) in VUV and X-ray regions. In High-Field Physics and Ultrafast Technology Laboratory at National Central University (NCU), an LWFA is being developed to produce a 250 MeV high-brightness electron beam by their 100-TW laser system. An FEL...
FEL oscillators can produce few-cycle optical pulses with a high-extraction efficiency when the oscillators are operated in the superradiant regime*. Such FEL oscillators are unique light sources to explore intense light field science, especially in mid-infrared and longwave infrared where ultrashort pulses are difficult to produce from conventional lasers. Since the laser-matter interaction...
The heavy ion synchrotron SIS100 is the flagship accelerator of the Facility for Antiproton and Ion Research (FAIR) currently under construction at GSI, Darmstadt. It will provide high intensity beams of particles ranging from protons to uranium ions at beam rigidities up to 100 Tm. Part of the machine protection system is an emergency beam dump that is partly inside the vacuum system and...
The generation of high--brightness electron beams is a crucial area of particle accelerator research and development. Photocathodes which offer high levels of quantum efficiency when illuminated at visible wavelengths are attractive as the drive laser technology is greatly simplified. The higher laser power levels available at longer wavelengths create headroom allowing use of manipulation...
Novel particle accelerators based on plasma technology allow a drastic reduction in size, due to the high accelerating field established inside plasmas, which are created and confined by specific devices. Plasma Wakefield Acceleration experiments are performed at the SPARC_LAB test facility (Laboratori Nazionali di Frascati - INFN) by using gas-filled capillaries, in which the plasma formation...
Xi’an 200 MeV proton application facility (XiPAF) upgrading project is now in the design phase. For the synchrotron of the project, the influence of the dipole and quadrupole errors on the closed-orbit distortion(COD) is a matter we must pay attention to. However, Before the synchrotron assembly is complete, we do not know the actual errors of magnets. So we set certain distribution for...
Variable polarization is a required feature of light sources employed to investigate the properties of matter. The possibility to select light polarization is, in particular, attractive for those experiments, which aim at exploring the local symmetry of the sample under scrutiny, e.g., the chirality of a molecule, or the presence of a net atomic magnetic moment. Moreover, several...
During the third operational run of the Large Hadron Collider at CERN, starting in 2022, the beam energy was increased to 6.8 TeV and the bunch population is planned to be pushed to unprecedented levels. Already in the first year of operation, beam stored energies up to 400 MJ were achieved. An improvement in cleaning performance of the LHC collimation system is hence required. In this paper...
A 70 MeV H- cyclotron system has been installed at the Institute for Basic Science (IBS) from Nov. 2021 as a driver for ISOL system. Internal beam was first accelerated in May 2022 and utilized to highly isochronize the magnetic field using Smith-Garren method. In June, a beam of 70 MeV was extracted to two beam lines and beam emittance was measured by variations of quadrupole strengths and...
LCLSII 1-MeV CW electron source was successfully commissioned 2018-2020. 100MeV injector system is being commissioned since summer 2022. CW RF operations for injector system is routinely established and e-beam is being ramped to very high rate. Ultra-low emittance has been achieved for desired charges. Dark current along the injector beam line is systematically characterized and mitigations...
In the framework of the injector upgrade, which has been completed in 2022 as the first stage of the FLASH2020+ project, a new second bunch compression chicane has been redesigned and installed at the FEL user facility FLASH. The old S-type chicane with a flat vacuum chamber design has been replaced with a movable C-chicane which round vacuum chambers. The inner dipoles and corresponding...
The Offline 2 mass separator laboratory is part of the CERN-ISOLDE Offline facilities - a suite of installations required to perform essential quality control on target and ion source units before irradiation at CERN-ISOLDE. The facility is also used for offline studies as a prerequisite before conducting any beam development on-line, especially establishing systematic effects. The Offline 2...
Dalian Coherent Light Source (DCLS) is an extreme ultraviolet free-electron laser (FEL). The measurement of the longitudinal phase space (LPS) of electron bunch is vital to a FEL facility. In order to measure the LPS, a S-band RF transverse deflecting cavity (TDS) has been installed and commissioned at DCLS facility. This paper will introduce the TDS physical layout and commissioning results...
Phase shifter collocated with undulator is an efficient way to enhance lasing of free-electron laser
(FEL), especially for seeded FEL. Dalian Coherent Light Source (DCLS) is a seeded FEL operating on
high-gain harmonic-generation (HGHG) mode. In order to achieve highly performance of FEL
lasing, five phase shifters are interspersed between six undulators. This paper will present...
The Frankfurt Neutron Source FRANZ will be a compact accelerator driven neutron source utilizing the 7Li(p,n)^7Be reaction with a 2 MeV proton beam. Recent comissioning efforts showed succesful proton beam operation at the targeted RFQ injection energy of 60 keV up until the point of RFQ injection. The RFQ was retrofitted with new electrodes for the injection energy of 60 keV. We report on the...
The Rare isotope Accelerator Complex for ON-line experiments (RAON) has been proposed as a multi-purpose accelerator facility for providing beams of exotic rare isotopes of various energies. It can deliver ions from hydrogen (proton) to uranium. Protons and uranium ions are accelerated up to 600 MeV and 200 MeV/u respectively. It can provide various rare isotope beams which are produced by...
Due to the limitations of Laser Produced Plasma (LPP) Extreme Ultraviolet(EUV) sources, semiconductor industry is seeking the next generation EUV source for sub-nm scale lithography processes. Various accelerator-based light sources have been already proposed as EUV lithography light sources. We investigated the design of a compact high-power EUV light source using laser Compton scattering....
In AXSIS project, we are developing compact, THz-based electron accelerators, which represent a promising technology for the development of next-generation compact electron accelerators that significantly downsize x-ray sources. A key aspect in such a design is transport and focusing of an electron bunch accelerated to 20 MeV kinetic energy to inverse-Compton scattering (ICS) like interaction...
Recent demonstrations of terahertz (THz) powered accelerators and beam manipulators have opened a pathway towards miniaturized accelerators that promise to enable new science due to unique features such as reduced timing-jitter and reduced space-charge broadening of the electron bunches. Here, we present on the development of a matchbox sized multi-layered accelerator structure powered by a...
In the frame of ongoing initiatives for the design of a new generation of synchrotron-based accelerators for cancer therapy with ion beams, an analysis of linac designs has been started, to address a critical element with strong impact on performance and cost of the accelerator. The goal is to identify alternatives at lower cost and similar or possibly smaller footprint than the standard 217...
The beam optics in the SNS normal conducting linac is analyzed for the 1.4 MW beam-on-target operation settings. The first section is a room temperature copper linac which include Medium Energy Beam Transport (MEBT) section with four re-bunching radio-frequency (RF) cavities, Drift Tube Linac (DTL), and Coupled Cavity Linac (CCL). The Radio Frequency (RF) cavities in this section accelerate H-...
The electron source is a critical component of the RUEDI (Relativistic Ultrafast Electron Diffraction & Imaging) facility, which needs to provide beam to match the re-quirements for performing both electron microscopy and ultrafast electron diffraction. To meet these demands, different operational modes are needed, to deliver ultra-short, ultra-bright and highly temporally and energy stable...
The IFMIF-DONES facility (International Fusion Materials Irradiation Facility – DEMO Oriented Neutron Source) is currently under design and being prepared for the construction phase within the framework of a EUROfusion Consortium work package. Its location will be in Escúzar, Granada and it will be the largest science and technology infrastructure project developed in Spain. Its objective is...
The SPES RFQ is designed in order to accelerate beams
in CW with A/q ratios from 3 to 7 from the Charge Breeder
through the MRMS and the selection and injection lines up
to the MEBT (Medium Energy Beam Transport). The RFQ
is composed of 6 modules about 1.2 m long each, made of a Stainless Steel Tank and
four OFE Copper Electrodes. A copper layer is plated on
the tank inner surface and a...
Laser wakefield acceleration (LWFA) using metal targets has been developed for high-vacuum and high-repetition rate operations compare to the gas targets[1-2]. However, the ionization effect due to high intensity fs laser should be considered as propagating through the plasma and the difference of LWFA mechanisms between aluminum plasma and helium plasma has been investigated with the...
The demand for muon facilities has been continuously increasing since surface muons play a significant role in particle and solid-state physics. The installation of a refurbished muon target station and two new High-Intensity Muon Beam lines (HIMB) in the framework of the Isotope and Muon Production using Advanced Cyclotron and Target technology project (IMPACT) at PSI will pave the way to...
The Isotope and Muon Production using Advanced Cyclotron and Target technology (IMPACT) project at the Paul Scherrer Institut aims to produce and fully exploit unprecedented quantities of muons and radionuclides for further progress in particle physics, material science and life science. The proposed Targeted Alpha Tumor Therapy and Other Oncological Solutions (TATTOOS) facility will provide,...
During the last run, the CLARA accelerator ran with a 2.5 cell 10 Hz S-band RF gun which had a modified back plate to allow the use of INFN-style photocathode pucks. Previously this gun had used a solid wall back plate that also acted as the photocathode*.
This presentation describes the different photocathodes that were used during the run and the various methods employed to prepare them...
Surface nanostructuring is a promising approach when it comes to improving the quantum efficiency (QE) of materials for electron accelerator purposes at CERN. This is due to the plasmonic effect taking place in metallic materials at the nanoscale, when an electromagnetic wave interacts with a sub-wavelength feature. Ultrafast laser surface nanopatterning can be an efficient and times saving...
Alkali antimonide photocathodes are promising candidates for many high-brightness electron sources due to their low-emittance and high quantum efficiency. However, these materials require ultra-high vacuum (UHV) storage and transport to avoid oxidation, which affects their performance. In this proceeding, we report the synthesis of cesium antimonide cathodes with different stoichiometric...
The so-called “green photocathodes”, based on alkali antimonide compounds, are characterized by high efficiency at green light wavelengths (1-10% at 500-550 nm) and excellent charge lifetime, but are easily poisoned in poor vacuum and are usually grown in form of disordered polycrystalline layers. Surface disorder is an extrinsic factor significantly contributing to reduce the transverse beam...
The compact ERL has been built as a test machine of energy recovery linac (ERL) at KEK in 2013. It has been succeeded to operate with 1 mA beam current with energy recovery mode in 2016. Recently, two undulators have been integrated into it to produce an infrared free-electron laser (FEL) light and the light amplification has been successfully observed with a burst mode and without energy...
Abstract: Electron Cyclotron Resonance Accelerator (eCRA) simulation results are presented for realistic TE111 cavity geometry and finite space-charge beams that confirm the single-particle idealized solutions. The simulations include cavity openings for RF inputs, beam injection, and pumping; RF input couplings that maximize efficiency; a thin window for exit of the accelerated beam;...
In high-gradient accelerator structures, field emission produces dark current that behaves much differently than the main photobeam current. This dark current can damage accelerator components and increase the radiation dose in the surrounding area. Thus it is important to analyze its behavior when designing a new accelerator or subsystem, such as the superconducting low-emittance injector...
An electron beam test stand was designed and constructed at CERN, under the umbrella of the Hi-Lumi project, to tests components for the Hollow Electron Lens (HEL), and in collaboration with the ARIES project for testing the Space Charge Compensation gun. The test facility features normal conductive magnets providing solenoid fields of the order of fractions of Tesla, beam diagnostics...
The Southern European Thomson back-scattering source for Applied Research (STAR) project, based on a collaboration among University of Calabria (UniCal), CNISM, INFN and Sincrotrone Trieste, has the goal to install and test at UniCal a short linear accelerator for high brightness electron beams that will drive a unique advanced X-ray Thomson source. In 2021 INFN was committed to install, test...
Dielectric wakefield acceleration (DWA) is a promising approach to particle acceleration, offering high gradients and compact sizes. However, beam instabilities can limit its effectiveness. In this work, we present the result of a DWA design that uses alternating gradients to counteract quadrupole-mode induced instabilities in the drive beam. Through simulation and experimental results, we...
We report our recent results on the project (XLO) to build, characterize and operate a population inversion x-ray laser at the copper $K{\alpha_1}$ line, using LCLS x-ray pulses as a pump. The results include: gain measurement; design, alignment and focusing elements for the optical bow-tie cavity; copper target measurement of damage caused by the pump pulses; development of a fast system to...
A planned experiment at the Argonne Wakefield Accelerator (AWA) facility will demonstrate the plasma photocathode concept, wherein precise laser-based ionization of neutral gas within the wakefield driven by a relativistic particle beam generates a high brightness witness beam, which is accelerated in the wakefield. Replacing the plasma wakefield acceleration component with a dielectric...
The Japan Atomic Energy Agency (JAEA) is designing a 30 MW continuous wave (cw) superconducting proton linear accelerator (linac) for the Accelerator Driven Subcritical System (ADS) proposal. The JAEA-ADS linac's source must provide a proton beam over 20 mA with an energy of 35 keV and a normalized rms emittance of less than 0.1 π mm mrad. As the extraction system determines the beam...
Structure-based wakefield acceleration with nanosecond-long RF pulses is a promising advanced accelerator concept to mitigate the risks of RF breakdown. Advanced structures are required to satisfy the need of a high transient gradient with a short pulse length. A metamaterial (MTM) structure, as a subwavelength periodic structure exhibiting a negative group velocity, could have a higher shunt...
Accelerators operating in the mm-wave regime can reach much higher gradients than conventional accelerators due to the favorable scaling of the breakdown threshold with frequency. These structures also have the potential to achieve a much higher shunt impedance, enabling the efficient use of RF power that is critical given the current limitations on high power RF sources in this regime. We...
The energy contained in the LHC's two beams must be safely absorbed in external beam dumps (TDE). High Luminosity (HL) is a future upgrade which will increase this stored energy to 700 MJ, compared to 150 MJ in Run 1. The TDE design has changed little since Run 1; it is a cylindrical stainless-steel vessel with a core made of graphite. During long shutdown 2 (LS2), upgrades were made to the...
The High Intensity and Energy ISOLDE facility (HIE-ISOLDE) at CERN has unprecedentedly expanded the research capabilities to investigate the structure of the atomic nucleus and the nuclear interaction. In this context, to meet the high-resolution mass spectroscopy required by the HIE-ISOLDE physics program, an innovative spectrometer is currently being designed, the ISOLDE Superconducting...
The generation of electron sources by high gradient laser wakefield acceleration (LWFA) has already demonstrated its feasibility. This acceleration technique is on the way to be implemented for practical uses by well-defined user communities. However, obtaining the required outstanding high-quality beams is a difficult challenge. Several key parameters, such as the laser distribution...
For the Linac travelling wave S-band injector at ELSA a new electron gun is being designed, to enhance the beam parameters of the old gun. Furthermore, a new single bunch injection mode is to be realized alongside the standard long pulse (multi bunch) mode, allowing to use the gun for normal operation for the experimental program as well as enabling single bunch operations for accelerator...
RI Research Instruments (RI) in partnership with The Canadian Light Source (CLS) have designed a new 250 MeV electron linac to inject into the 0.25-2.9 GeV booster synchrotron. The RF frequency is 3000.24 MHz, the sixth harmonic of the 500.04 MHz booster and storage ring RF cavity frequency, and the main accelerating sections consists of three 5 m constant gradient accelerating structures. The...
The quarter wave resonator (QWR, a.k.a. λ/4 resonator) for the new ISIS MEBT is a bunching cavity that longitudinally compresses the H- beam into smaller bunches. It has 2 gaps with a distance of βλ/2 between mid-gaps, and works in π mode at the resonant frequency of 202.5 MHz, with a phase angle of -90 degrees. The maximum voltage per gap (E0L) is set to 55 kV. A detailed RF model has been...
Chopper systems are typically used to provide beam time structure and ensure the safety of accelerator operations by deflecting the beam away. The reliability of conventional chopper is entirely based on high-voltage (HV) pulsed power supplies, and when it fails to charge the electrostatic deflection plate, the beam cannot be cut off and will enters the downstream accelerator. To meet the...
The electrostatic chopper for the new ISIS medium-energy beam transport (MEBT) is a fast deflecting device to create gaps in the beam coming out of the RFQ, which will improve the trapping efficiency when injecting the beam into the ISIS synchrotron. Due to the stabilization time required by the ion source, it is expected that the first 100 μs of the 400 μs pulse need to be removed in order to...
Proton FLASH, which combines the advantages of a better spatial dose distribution of protons with the unique temporal effect of FLASH radiotherapy, is currently a hot topic of international research. Proton FLASH radiotherapy is technically demanding and currently lacks equipment support. There are only a few devices that have been modified to achieve small target section, fixed-energy...
This poster will describe the design of the photocathode plug for CARIE. Photocathodes are used to produce beams for a variety of accelerator applications, including colliders, UED, and FELs. Thin film semiconductors offer ways to increase QE, reduce MTE, and increase beam brightness, but are very sensitive to chemical contamination and have never been tested under high gradients or...
X-band high gradient accelerating technology is a challenging and important technology in advanced electron linear accelerator facilities. The X-band accelerating structure can provide harmonic compensation to eliminate non-linear energy spread and realize linear compression of bunch in linac. In this paper, a special X-band traveling-wave accelerating structure is designed for linearizer,...
The matter-antimatter asymmetry might be understood by investigating the EDM (Electric Dipole Moment) of elementary charged particles. A permanent EDM of a subatomic particle violates time reversal and parity symmetry at the same time and would be, with the currently achievable experimental accuracy, an indication for further CP violation than established in the Standard Model.
The...
A novel 704.4 MHz CH structure is under develop-ment. Due to its relatively small spatial dimensions (22 cm in diameter and 33.7 cm in length), the additive manufacturing (AM) technology is an attractive choice for the construction. For a proof of concept, a simplified model with one stem, one drift tube, and a small part of another stem was printed with copper. This structure was also...
We have been developing a backside laser-heated thermionic electron gun with a tripolar tube structure for a compact electron accelerator driven neutron source. A lanthanum hexaboride (LaB6) emitter is heated by irradiating a near-infrared laser light transported by an optical fiber to the back of it in this electron gun even though there was no heater wire. The LaB6 electron source with a...
Ultrafast electron diffraction (UED) is a powerful tool for the direct visualization of structural dynamic process-es in matter on atomic length and time scales. Observa-tions on a femtosecond time scale with atomic resolution spatially have long been a goal in science and are current-ly achieved with large photo injectors developed for FEL frontends. Here we demonstrate a compact 180 keV...
Two new eddy-current-type septum magnets were installed at the fast extraction section of J-PARC main ring in April 2022. Eddy septum magnets (EDDYs) are energized pulse currents; thus, it is necessary to consider the possibility of misfires. Based on simulation results, if one of the EDDY misfires, the extraction beam will be irradiated to the ducts of the superconducting magnets (SCs) on the...
Non-destructive beam diagnostics as well as experiments and light sources that have a low impact on the beam are important for the operation and applications of an Energy-Recovery LINAC (ERL). Compton backscattering can provide a quasi-monochromatic highly polarized X-ray or gamma-ray beam without strongly affecting the electron beam due to the small cross- section of the Compton scattering....
Spin is one of the intrinsic properties of particles. However, there are many incomprehensible problems about it. High energy polarized electron-ion collisions will provide unprecedented conditions for the study of spin physics and lead us to the study on the inner structure of matter and fundamental laws of interactions, and other forefronts of natural science. As the Phase II of the HIAF...
An ultrahigh dose rate (UHDR) MV-level X-ray radiation platform for FLASH radiotherapy (RT) research based on a normal conducting linear accelerator is presented in this work. A S-band backward traveling-wave linear accelerator powered by a commercial klystron produces electron beams with 11 MeV energy, 300 mA pulse current, and 2.6 mA mean current at 0.88% beam duty ratio. The radiation...
Short bunch electron beam from linear accelerators can produce broad band and Carrier Envelope Phase fixed coherent radiation in THz spectrum range via various schemes, such as Coherent Synchrotron Radiation and Coherent Transition/Diffraction Radiation. Especially in the high-repetition (or multi-bunch) linac, a CEP-fixed mono-cycle THz pulse train will be available. In order to realize a...
A ultra-low emittance electron source utilizing laser-cooled neutral gas as the photo-ionization source has been developed in several laboratories in the accelerator community. We have started the development aiming for using the electron source for the injector of a THz accelerator which has a small aperture and requires a high quality beam.
As the first stage of the development work, we...
Tokyo Institute of Technology is planning a linac facility to produce 211 astatine, an isotope for αemitter cancer therapy. To produce astatine, we aim to bombard a bismuth target with helium ion beam of sufficient intensity at 28 MeV. Unlike a cyclotron, this facility will be able to accelerate a milliampere class high intensity helium ion beam. In addition, the subsequent accelerator...
Polarized beam is an effective tool in basic research. An Electron-ion collider in China (EicC)*, as a future high energy nuclear physics project, has been proposed. Eicc can provide good research conditions for precision measurements of the partonic structure of nucleon or nuclei and the study on the interactions between nucleons and so on. High quality polarized beam is helpful to the...
The proposed Targeted Alpha Tumor Therapy and Other Oncological Solutions (TATTOOS) facility at the Paul Scherrer Institute aims to produce radionuclides, especially alpha-emitters, via proton-induced spallation for potential clinical studies of advanced cancer treatments. This new 100 microA / 590 MeV proton beamline delivers in the best-case scenario 26 kW to the target.
In this study, a...
The natural time scale of quantum mechanical motion of electrons in molecules is usually on the order of hundreds of attoseconds. Probing time-dependent dynamics with atomic-site specificity on such timescales requires the generation of soft X-ray attosecond pulses pairs with variable delay and synchronization down to the sub-femtosecond level. We report the generation of GW-level attosecond...
Beam uniformity is an important factor that must be considered in slow extraction optimization, and the tune ripple caused by the power supply ripple is an important factor
that causes beam uniformity to deteriorate. In this study, based on the beam excitation concept for two regions (extraction and diffusion regions), a differential equation of
beam spill under the influence of a mono...
Future colliders will require injector linacs to accelerate large electron bunches over a wide range of energies. For example the Electron Ion Collider requires a pre-injector linac from 4 MeV up to 400 MeV over 35 m [1]. Currently this linac is being designed with 3 m long traveling wave structures, which provide a gradient of 16 MV/m. We propose the use of a 1 m distributed coupling design...
Linear induction accelerators such as the DARHT at Los Alamos National Laboratory are used as sources for flash x-ray diagnosis of dynamic events. The source characteristics of primary interest are the source intensity, the source spot-size, and the illumination uniformity which are determined by the electron beam parameters. We utilize self-developing x-ray film to characterize the x-ray...
Background and aim: The potential of a compact, laser-based ion accelerator for radiobiological and medical applications relies heavily on the control of the laser-target source and on the use of custom beam transport and delivery to the final target. Here we show the results of an experimental campaign dedicated to the dosimetry of the beam at the crosswire and the first radiobiological...
Solid-state plasma wakefield acceleration might be an alternative to accelerate particles with ultra-high accelerating gradients, in the order of TV/m.
In addition, due to their thermodynamic properties, 2D carbon-based materials, such as graphene layers and/or carbon nanotubes (CNT) are good candidates to be used as the media to sustain such ultra-high gradients. In particular, due to...
Vertical orbit excursion Fixed Field Accelerators (vFFAs) feature highly non-linear magnetic fields and strong transverse motion coupling. The detailed study of their Dynamic Aperture (DA) requires computation codes allowing long-term tracking and advanced analysis tools to take the transverse motion linear and non-linear coupling into account. This coupling completely transforms the beam...
Following the successful Run 1 experiment, AWAKE has developed a program for Run2 that requires designing and implementing a compact electron source (150 MeV, >= 100 pC) for external injection. The baseline design uses a S- and X-band RF photo-injector gun system. The project EARLI investigates the feasibility of an alternative electron source system using a laser wakefield accelerator (LWFA)...
High temperature superconductor REBCO has the property of maintain a high critical current density under strong external magnetic field, which makes a promising material for electromagnets in cyclotron and ECR ion source. Therefore, an ECR ion source using iron-less REBCO coils as electromagnet is under development in Research Center for Nuclear Physics (RCNP), Osaka University. A coil system...
Several concepts for future linear colliders are dependent on very high gradient normal conducting RF cavities achieved by operation at cryogenic temperatures in order to reduce breakdown rates (BDR). These maximum fields are intended to be in excess of 200 MV/m. The concepts include the ultra compact Xray free electron laser and the C$^3$ collider. The theory involved with the complex physics...
Plasma accelerators can sustain accelerating gradients of up to ~100 GeV/m.
However, reaching the high energies required for future particle colliders requires the acceleration to be performed in multiple plasma stages.
Solving the challenges posed by multistage acceleration, such a beam quality preservation, requires the capability of simulating large chains of accelerating stages,...
In this paper, we present the benchmark results of Bmad space charge tracking on the Electron-Ion Collider cooler injector lattice. Bmad, GPT, and Impact-T are compared in terms of accuracy and performance. We highlight the importance of space charge algorithm and demonstrate that the adaptive step size control improves the performance of Bmad space charge tracking.
The 800-MeV proton linac at the Los Alamos Neutron Science Center (LANSCE) includes a drift-tube linac, which brings the beam to 100 MeV, followed by a coupled-cavity linac (CCL) consisting of 44 modules. Each CCL module contains multiple tanks, and it is fed by a single 805-MHz klystron. CCL tanks are multi-cell blocks of identical re-entrant side-coupled cavities, which are followed by...
The interest in plasma-based accelerators as drivers of user facilities is growing worldwide thanks to their compactness and reduced costs. The EuPRAXIA@SPARC_LAB collaboration is preparing a technical design report for a multi-GeV plasma-based accelerator with outstanding electron beam quality to pilot an X-ray FEL, the most demanding in terms of beam brightness. The beam dynamics has been...
Ultrafast electron probing techniques offer unique experimental tools for investigating the structural dynamics of ultrafast photo-induced processes in molecular and condensed phase systems. In this work, we propose using the SEALAB Photoinjector's exceptional and versatile electron beam parameters to develop a state-of-the-art facility for ultrafast electron diffraction and imaging (UED and...
Laser-generated terahertz frequency pulses have been used to manipulate the phase-space of electron beams at the CLARA test facility.
Acceleration gradients of 20 MeV.m$^{-1}$ were achieved in dielectric lined waveguides with narrow-band 400 GHz sources with MW peak powers, and with bunch charge from 2pC to 100pC.
The high-frequency of the acceleration field provided an extremely fast...
An Inverse Compton Scattering (ICS) X-ray source is under development at the ELSA electron RF linac of CEA DIF. The X-rays are emitted by the interaction of a 30-MeV electron bunch with a visible (532nm) or infrared (1064nm) Nd:YAG laser pulse. The radiation spectrum lies in a 10-100 keV range. The electron bunches duration is 30 ps after compression in double-alpha magnets. In such a system,...
Blow-out beam generation is an established method to generate uniformly-filled ellipsoidal electron bunches by illuminating the cathode by an ultrashort laser pulse having a parabolic-like transverse profile of laser intensity. A theoretical study of blow-out generation in an APEX-like ultrahigh frequency RF gun revealed emittance oscillations and self-compensation at the gun exit without any...
The high-voltage modulators of the 26 klystrons in the XFEL represent the largest power consumer of the accelerator facility. The beam energy is usually 14 GeV, but a few weeks a year, lower and higher beam energies are also produced. For example, 11.5 and 16.3 GeV. Until mid-2022, the modulator voltages were set so that enough RF power for 16.3 GeV beam energy could be provided at all times....
Recently, RadiaBeam has designed, manufactured, high power tested and delivered a robust production ready S-Band thermionic RF gun with optimized electromagnetic performance, improved thermal engineering and robust yet precise cathode mounting technique. This gun will facilitate performance improvements of existing and future light sources, industrial accelerators, and electron beam driven...
Externally seeded free-electron lasers are promising for generating intense, stable, and fully coherent soft X-ray pulses. An earlier study demonstrates that high brightness and coherent soft X-ray radiation can be produced based on coherent harmonic generation and superradiant principles, termed high-brightness high-gain harmonic generation (HB-HGHG). However, due to the limitations of...
RUEDI (Relativistic Ultrafast Electron Diffraction & Imaging) is a proposed facility which will deliver single-shot, time-resolved, imaging with MeV electrons, and ultrafast electron diffraction down to 10 fs timescales. RUEDI is being designed to enable the following science themes: dynamics of chemical change; materials in ex-treme conditions; quantum materials; energy generation, storage,...
The J-PARC Main Ring (MR) delivers high-intensity proton beams for
the neutrino experiment.
The beam intensity delivered to the neutrino experiment reached 520kW with a cycle time of 2.48 seconds in 2021.
We chose to shorten the MR cycle time to 1.36 seconds to achieve higher beam intensity.
An anode power supply feeds a high-voltage DC current to the tetrode vacuum tubes, which drive...
EuPRAXIA is the first European project that develops a dedicated particle accelerator research infrastructure based on novel plasma acceleration concepts and laser technology. It focuses on the development of electron accelerators and underlying technologies, their user communities, and the exploitation of existing accelerator infrastructures in Europe. It was accepted onto the ESFRI roadmap...
At the University of Melbourne X-LAB we are investigating the use of a low (\beta) acceptance X-band accelerating structure as part of the design of an all X-band RF electron preinjector optimised for the production of low emittance electron bunches for medical physics applications and compact light source development.
In this work we will elaborate on the estimated performance, design...
Electron beams with a flat-top transverse distribution are highly desired for uniform dose delivery in irradiation applications, like studies of radiation damage to electronics and radiotherapy, as well as for potential applications in the improvement of light sources. In this work, we report on the optimization of the electron photocathode injector parameters which allow such uniform...
In the high gradient rf photoinjectors, dark current is the “unwanted beam” not produced by the cathode drive laser. It is a part of field emission from the cavity and photocathode, which is accelerated through the gun. Dark current can cause beam loss, increase the risk of damage to accelerator components, and create additional background for beam users. Furthermore, during operation of the...
Typically, in Self-Amplified Spontaneous Emission Free Electron Laser (SASE FEL) based short-pulse schemes, pulse duration is limited by FEL coherence time. A method, proposed in [1], allows to overcome the coherence time barrier and to get much shorter pulses. When lasing part of an electron bunch is much shorter than coherence time, one can suppress the radiation in the long main undulator...
At iThemba Laboratory for Accelerator Based Sciences (LABS), particle beams are pre-accelerated in a K8 injector cyclotron and further accelerated in a K200 Separated Sector Cyclotron. The accelerated beams are transported to various target stations, including targets stations used for radionuclide production and fundamental subatomic physics research. All along the trajectory of the beam...
D-Pace has a self-heated hot-cathode Penning ion source test stand at their Ion Source Test Facility (ISTF). High-charge state production of boron, arsenic, and phosphorous is interesting to the ion implantation industry, as it allows for higher energy implants of these dopants using the same accelerating gradient in a given accelerator system. We use Neon and Krypton as proxy gases to...
Our laboratory has been studying about polymer electrolyte membrane (PEM) for polymer electrolyte fuel cell (PEFC) by irradiation graft polymerization using electron beam accelerator. Irradiation graft polymerization can reduce the production cost of the PEM compared with the current product, perfluoro-sulfonic acid (PFSA) ionomer such as Nafion®︎ by DuPont. We have two methods to fabricate...
The Japan Atomic Energy Agency (JAEA) has been proposing an accelerator-driven system (ADS) as a future nuclear system to efficiently reduce high-level radioactive waste generated in nuclear power plants. As a first step toward the full-scale design of the CW proton linac for the JAEA-ADS, we are now prototyping a low-beta (around 0.2) single-spoke cavity. The actual cavity fabrication started...
The future Accelerator Facility for Antiproton and Ion Research (FAIR) belongs to the category of international mega-projects and is under construction in Darmstadt, Germany. The FAIR project includes the construction of 24 accelerator and experimental buildings with a total area of about 150,000 m2, as well as 12 sub-projects in the areas of accelerators (pLINAC, SIS100, SuperFRS, p-bar, CR,...
A fast neutron facility, called NDPS (Nuclear Data Production System), has been constructed for nuclear science and applications at RAON (Rare Isotope Accelerator complex for ON-line experiments) in Korea. The installation of NDPS and transport beamline from SuperConducting LINAC 3 (SCL3) to NDPS was finished in 2022. The NDPS is designed to provide both white and mono-energetic neutrons,...
The 3.2 GeV electron stretcher facility ELSA at the University of Bonn provides electron beams for fundamental research in hadron, detector and medical physics. The beam is extracted from a storage ring, whose injector consists of a 26 MeV linear accelerator and a 1.2 GeV booster synchrotron. The advent of functional plasma-based electron injectors in the MeV energy range raise the opportunity...
We study the feasibility for a hard x-ray FEL oscillator (XFELO) at 3 GeV based on harmonic lasing and transverse gradient undulator (TGU) with strong focusing. We carry out optimization of parameters using the formula developed in 2021 [1] for harmonic lasing XFELO with TGU and strong focusing. From previously assumed x-ray cavity loss of 30-20%, we lowered the assumed cavity loss to 5%...
One of the limitations in structure wakefield acceleration is large transverse emittances of high-charge wakefield drivers. The simplest idea to avoid this issue would be to prepare multiple lower-charge drivers and apply RF power from all drivers to a single accelerating tube. However, the method has two significant drawbacks; cost and timing control. We propose a single high-charge beamline...
The photon energy in the soft X-ray range corresponds to the fundamental absorption edges of matter. Ultrashort X-ray pulses can be used to observe the breaking of chemical bonds in biochemical reactions and capture the transfer process of electrons in ultrafast physical phenomena, which is of great significance for the research of the next generation of semiconductor materials, such as...
We present an overview of the FERMI seeded free electron laser (FEL) facility located at the Elettra laboratory in Trieste, Italy. FERMI, in operation with both FEL lines FEL-1 and FEL-2 since 2012, covers the spectral range between 100 nm and 4 nm with light characterized by variable polarization, narrow spectral width, stable intensity and central wavelength. A series of infrastructure...
The upgrade of the single cascade FEL-1 of the FERMI free-electron laser, aiming at implementing operation either in Echo Enabled Harmonic Generation (EEHG) or in High Gain Harmonic Generation (HGHG) mode, has started. We have recently modified the layout in order to crate the space required for the installation of the large dispersive section needed for the EEHG scheme. As a result, the...
As an option for the proton driver for the next generation spallation neutron source (ISIS-II) at the Rutherford Appleton Laboratory (RAL), a Fixed Field Alternating Gradient Accelerator (FFA) is being considered. A prototype accelerator has been designed, referred to as FETS-FFA, to demonstrate flexible handling of beam repetition for users and high intensity operation with minimum beam loss....
Fixed field Alternating gradient (FFA) accelerator is an option as a proton driver for the next generation spallation neutron source (ISIS-II). To demonstrate FFA suitability for high intensity operation, a 3 to 12 MeV proton prototype ring is planned at RAL, called FETS-FFA. The main magnets are a critical part of the machine, and several characteristics of these magnets require development....
The cyclotron C70XP of the Interest Public Group ARRONAX is regularly producing radio-isotopes for medical and research purposes. To support these productions an internal data network based on EPICS has been deployed, extending the collection of data on the accelerator components and, beam and technical diagnostics. With the accumulation of the new data, a study program is being addressed...
Within the framework of FLASH2020+, substantial parts of the injector of the FEL user facility FLASH have been upgraded during a nine-month shutdown in 2022 to improve the electron bunch properties in preparation for FEL operation with external seeding starting in 2025. As part of the injector upgrade, a laser heater has been installed upstream of the first bunch compression chicane to control...
We report a first observation of terahertz super radiant emission from the Israeli Free Electron Laser. This is the first demonstration of a THz source based on the scheme of coherent spontaneous superradiant emission by an ultra-short e-beam bunch [1].
The FEL is driven by a compact (64 cm long) Hybrid photo-cathode RF gun, emitting a beam of electron with kinetic energy of 3.5 to 8.5 MeV...
X-rays production through betatron radiation emission from electron bunches is a promising resource for several research fields. In the framework of EuPRAXIA project, EuAPS (EuPRAXIA Advanced Photon Sources) project has the purpose to provide a compact, plasma based line designed to exploit internal injection processes occurring in laser-plasma interaction to drive electron betatron...
The importance of coherent brilliant light sources for research and industry makes free electron laser (FEL) facilities a cornerstone of today’s science. The improvements of such facilities are of great importance. Here I present the first steps to enhance the undulator sections in FEL facilities by adding a plasma inside the undulator [1]. Instead of propagating the electron beam in vacuum...
A research project was initiated at HZB to develop a new E-Gun control system for the Linac Gun to realize the advanced demands from the BESSY II injection scheme. The Flexi-Gun system will allow significantly higher flexibility in both pulse load and pulse timing structure. The purpose built gun test stand is equipped with a diagnostic beamline. Developed and manufactured in-house, the...
A Gabor-lens is an ion optical device using the electric self-field of a stable confined electron column providing the focusing strength. This lens type was investigated in detail and it was shown that it is possible to use it in a LEBT for intense heavy ion beams. The homogeneous electron density results in linear focusing forces and provides space charge compensation of the beam. On the...
The lateral position deviation between the electron beam and undulators will lead to an interaction area decrease in practical high-gain free electron laser (FEL) equipment. Corrector magnets can be modified in the FEL control system to regulate the electron beam trajectory and promote laser power. Tuning tasks are time-varying, drifting, and multi-dimensional, and manual tuning by operators...
Energy recovery linacs (ERLs) possess bright prospect of the fully coherent x-ray generation. Recently, we designed a 600 MeV energy recovery linac capable of producing high power fully coherent radiation pulses at 13.5 nm with a relatively low-intensity 256.5 nm seed laser profited from the employment of angular-dispersion-induced microbunching (ADM) technology. We also designed a matched...
A compression of the ESS proton pulse from the present 2.86 milliseconds to a few tens microseconds which is better matched to the moderator time constant of thermal neutrons would considerably boost the performance for many instruments at ESS. Generating such a proton pulse with preserved instantaneous beam power requires a storage ring to be added to the ESS accelerator. Such a ring has been...
The Los Alamos Neutron Science Center (LANSCE) is a MW-class H-/H+ 800-MeV proton linear accelerator and storage ring that serves five distinct user facilities in support of LANL’s national security mission and DOE’s Office of Science medical isotope program. We will describe future directions of LANSCE over the next two decades, which includes revitalization and modernization of existing...
Attosecond soft x-ray pulses is of great importance for the study of ultrafast electronic phenomena. In this paper, a feasible scheme is proposed to generate isolated fully coherent attosecond soft x-ray free electron laser via optical frequency beating. Two optical lasers with the opposite chirp are used to induce a gradient frequency energy modulation, which helps to generate a gradually...
This article presents a study on the H11(0) end cell of an IH-DTL prototype for accelerating carbon ion beams from 5 to 5.5 MeV/u, which is designed for a hadron therapy linac injector. The voltage across the first and last gap in a drift tube linac tends to drop from a typical uniform voltage distribution along the inner cells. In the case of an IH cavity, the power cost to supply the...
A periodic system of spirally arranged magnetized annular sectors creates near the axis a helical field, which is close in structure and magnitude to the field in the set of helical magnets. Such a system of relatively few available magnets can be easier to manufacture and assemble than a system containing magnetized helices made from a single piece. In this paper, we theoretically study the...
With the best of modern standard lasers, high-energy gamma gamma (gg) colliders from electron beams of E > 250 GeV are only possible at the expense of photon luminosity, i.e. 10 times lower than for photon colliders at c.m. energies below 0.5 TeV. For existing state-of-the art lasers, an optimistic upper energy limit for x=4.8 is an electron beam of less than 250 GeV. We show how a single FEL...
The 3-GeV RCS at J-PARC at present operates at a relatively high intensity beam of nearly 1 MW for the spallation neutron source. The beam loss and the corresponding residual radiation, which is the key limitation against beam intensity ramp up, has been well mitigated to a minimum level in a recent series of beam studies and feedback from realistic numerical simulations. The residual beam...
Varex Imaging High Energy Sources Group has developed, built, and tested a Diode Electron Gun (DEG) based 6 MeV Accelerator Beam Centerline ABC-6-S-X-D, which showed excellent performance results, and has been entered into a serial production. The ABC is very similar in performance to its Varian-produced counterpart and may be used as its drop-in replacement in the existing installed Varex...
The high-intensity, polarized electron source is a critical component for the electron-ion collider which requires a polarized electron gun with higher voltage and higher bunch charge compared to any existing polarized electron source. At Brookhaven National Laboratory, we have built and successfully conditioned the inverted HVDC photoemission gun up to 350 kV. We report on the performance of...
A typical commercially available thermionic triode e-gun operates in 10-15 kV range. Certain linac accelerating structures may benefit from higher voltage injection. Based on commercially available low voltage e-guns Varex Imaging High Energy Sources Group has developed an e-gun that could be operated in extended range of voltages of 10-40 kV, provides high adjustability of injecting beam...
A unique feature of the current LANSCE accelerator facility is acceleration of four H- beams (differing in time structure) and one H+ beam. This is achieved by utilization of an injector system based on two ion sources (H+/H-), and a combination of chopper and RF bunchers in the Low Energy Beam Transports. Since the end of 1990’s, the large LANSCE experimental, Area-A, has been largely unused....
Novel accelerator concepts such as all-optical terahertz (THz) based compact accelerators demand high-power THz sources that are robust in order to enable reliable testing. THz sources based on the tilted-pulse front scheme have become the method of choice for table-top, high-energy, single-cycle (SC) THz generation due to both their versatility and scalability. However, due to the...
Cavity-based FELs, including x-ray free electron laser oscillators (XFELO) and x-ray regenerative amplifiers (RAFEL), have been proposed to generate fully coherent x-rays at high repetition rates. Among them, the oscillator-amplifier scheme can be used to generate high-brightness x-ray beams. Motivated by this technique, we propose a promising scheme to generate a fully coherent x-ray seed...
Increasing energy of proton beam at the Los Alamos Neutron Science Center (LANSCE) from 800 MeV to 3 GeV will improve radiography resolution ten-fold. This energy boost can be achieved with a compact cost-effective linac based on normal conducting high-gradient (HG) RF accelerating structures. Such an unusual booster is feasible for proton radiography (pRad), which operates with short beam...
Ultrafast science has developed rapidly nowadays thanks to the development of optical and laser technologies, like chirped pulse amplification and high-harmonic generation. In this work, a simulation has been performed to generate high-power femtosecond free-electron laser pulses with chirp pulse amplification in echo-enable harmonic generation. Numerical modeling shows that the peak power...
The C-band electron gun is an attractive option for lower emittance with compactness. In this paper, a new C-band photocathode gun has been developed. The electron gun experienced a high-power test and had preliminary reached the designed gradient on the cathode. The high-power test results are the basis of the beam dynamics design and beam testing.
The production of soft to hard x-rays (up to 25 keV) at XFEL (x-ray free-electron laser) facilities has enabled new developments in a host of disciplines. However, there is great potential for new scientific discovery at even higher energies (42+ keV), such as those provided by MaRIE (Matter-Radiation Interactions in Extremes) at Los Alamos National Laboratory. These instruments can require a...
Charged particles moving through a carbon nanotube may be used to excite electromagnetic modes in the electron gas produced in the cylindrical graphene shell that makes up a nanotube wall. This effect has recently been proposed as a potential novel method of short-wavelength-high-gradient particle acceleration. In this contribution, the existing theory based on a linearised hydrodynamic model...
Within the EU-funded activity IFAST, the task REX (Resonance Extraction Improvement) was launched in 2021 as WP 5.3. The IFAST-REX consortium comprises European hadron synchrotron facilities CERN and GSI, the hadron therapy centres CNAO, HIT, MedAustron, MIT and SEEIIST, as well as the companies Barthel HF-Technik and Bergoz Instrumentation. It deals with the crucial challenge of slow...
Insertion devices may be also very detrimental for the dynamic aperture of storage rings, since they introduce linear and higher order perturbations on the optics of synchrotrons. It is essential to study these effects to adjust the lattice to compensate for these terms when possible (high order multipole magnets are present in the lattice of the machine), or optimize the design of the IDs to...
J-PARC Main Ring delivers 65 kW (7x10^13 ppp) slow-extracted beam over 2 sec. at 30GeV to the hadron experimental hall to drive various nuclear and particle physics (hadron) experiments. Unexpected behavior of the high-intensity beam caused by the accelerator trip could cause serious machine damage. In March 2021, the first electrostatic septum (ESS1) was broken by a bump orbit distortion...
Many experiments in biomedicine, security imaging, and condensed matter physics require high brilliance and moderate electron beams. The properties of the photo electron source is defined by the photocathode quality such as low thermal emittance, fast response time, high quantum efficiency (QE) and the photocathodes’ robustness.
Metal cathodes are commonly used in RF Guns because they work...
As the intensity and power quest continue to increase in several physics experiments, collective effects become more limiting, and curing them becomes more involved. Therefore, an accurate description of the machine components is required to investigate such effects. In this work, we present an impedance model for the Fermilab Recycler Ring. We quantify the impedance of several elements in the...
Acceleration grids of the Neutral Beam Injector in nuclear fusion reactors must be extremely accurate and satisfy specific geometrical requirements to work properly. The implementation of the additive manufacturing technology was proposed since 2017 starting the characterization of pure copper up to the recent excellent results in terms of density, process reliability and repeatability. To...
Requirement of availability of CiADS (China Initiative Accelerator Driven System) is greater than 0.8. As a part of CiADS, high power RF system, including SSA (solid-state amplifier), high power transmission line, which availability should greater than 0.999. And hot-plug technology is a significant way to improve availability of SSA. But in the process of hot-plug, there will exist high power...
Antiprotons are generated at CERN by extracting a high-intensity proton beam
from the Proton Synchrotron (PS) onto a target. The resulting antiprotons are
captured in the Antiproton Decelerator (AD) ring. As the AD is about three
times shorter than the PS, the entire primary proton beam must be compressed
to less than one third of the PS circumference. The previous batch...
Transfer lines provide the beam transport from accelerators to experimental areas. In the study presented in this paper, commonly used beam optics are supplemented by Gabor-lenses (GL) to investigate their effect on the luminosity for fixed-target experiments.
With GLs it is possible to confine a pure electron plasma with densities up to 10E15 m-3. The self-field of the homogeneous electron...
The oscillator-type mid-infrared free-electron laser (FEL) at Kyoto University named Kyoto University FEL (KU-FEL) has achieved the extraction efficiency of 9.4%. A 1-D simulation predicted that the extraction efficiency can be further increased by reducing the optical cavity loss or increasing FEL gain*. A new photocathode RF gun is installed for increasing the FEL gain by increasing the...
Free-electron lasers (FEL) producing ultra-short X-ray pulses with high brightness and continuously tunable wavelength have been playing an indispensable role in the field of materials, energy catalysis, biomedicine, and atomic physics. A core challenge is to maintain and improve the transverse overlap of the electron and laser beams. This requires high-dimensional, high-frequency, closed-loop...
The minimum emittance of ion beams achieved using electron cooling is limited by the heating processes of Intra Beam Scattering and diffusion driven by resonance crossing of particles due to space-charge. We describe a new experiment to explore the intense space-charge regime with a transverse tune shift approaching -0.5 using 2.5 MeV protons at the Integrable Optics Test Accelerator (IOTA) at...
Thomson/Compton scattering is a method to produce high energy photons through the collision of low energy photons in a laser pulse onto relativistic electrons. In the linear (incoherent) Thomson/Compton regime, the flux scales linearly with the number of primary particles and the bandwidth of the produced photons depend, amongst other factors, on the energy spread of them. In general, an...
It has been known for decades that the intensity fluctuations of free-electron laser radiation conceal some information about the temporal characteristics of the light. In particular, by measuring the ensemble-averaged spectral intensity correlation function, one can reconstruct the average length of the x-ray pulse [1]. This method in its original form starts to break down once the electron...
MedAustron is a synchrotron-based ion cancer therapy facility located in Austria. Patients are treated with proton and carbon ion beams in an energy range of 62-252 MeV and 120-402 MeV/u, respectively. The facility features three clinical irradiation rooms, among which horizontal and vertical beam lines as well as a proton gantry are available for treatment. A fourth irradiation room is...
MedAustron is an ion therapy facility for protons and carbon ions located in Wiener Neustadt, Austria. The beam is presently extracted for clinical operation from the synchrotron with third-order resonant slow extraction via acceleration with a betatron core. However, due to the flexibility of the synchrotron operation for Non Clinical Research (NCR) purposes, other extraction methods can be...
Intra-atomic dynamics are fundamental to organic processes such as photosynthesis. X-Ray spectroscopy, using pulses of tens of femtoseconds durations generated by Free Electron Lasers (FELs), has enabled great progress in understanding this field. Sub-femtosecond pulses would enable new discoveries in the ultrafast timescales of reactions and transitions. In this paper, attosecond pulse...
Radio Frequency Knock Out (RF KO) extraction is used to extract stored particle beams from synchrotrons through transverse excitation, delivering spills of particles for experiments and medical therapy. Minimizing the fluctuations of spill intensity is vital to prevent detector pile-up and interlocks while making most efficient use of the extracted beam. To improve the spill quality, different...
Hard X-ray Self-seeding (HXRSS) is a well-know scheme to obtain longitudinally coherent FEL pulses with single SASE mode selected by a crystal. However, multi-modes can also be produced if the electron beam contains lasing parts with different energy chirp slopes (i.e. nonlinear chirp). At the European XFEL we have observed HXRSS with multi-modes and investigated its origin both in simulation...
The High-Luminosity LHC (HL-LHC) project at CERN aims at doubling the beam intensity and the brightness. To achieve this unprecedented performance, the LHC injectors were upgraded during the Long Shutdown 2 (2019-2021) to overcome limitations such as space charge and beam instabilities. Despite these upgrades, the reduction of beam loss on the flat bottom in the Super Proton Synchrotron (SPS)...
The Fermilab 750keV injector sends 25mA H- beam for 30µs at a rep-rate of 15Hz. The beam transmission through the FNAL injector is currently less than 50% from the ion source to the entrance of the drift tube linac. Recently it was uncovered that the primary loss point is within the region prior to the RFQ which houses the solenoid focal elements that match the beam to the RFQ. With recent...
The muonium is the bound state of the positive muon and the electron. The muoium can be ionized using a dedicated laser to produce the ultra-slow muon beam. It is one idea that the dense electrons may be used as a substitute of the ionization laser for the muonium. The preliminary study is reported for the ionization of the muonium using the electron.
The IOTA Proton Injector (IPI), currently under installation at the Fermilab Accelerator Science and Technology facility, is a beamline capable of delivering 20-mA pulses of protons at 2.5 MeV to the Integrable Optics Test Accelerator (IOTA) ring. First beam in the IPI beamline is anticipated in 2023, when it will operate alongside the existing electron injector beamline to facilitate further...
CLARA at STFC Daresbury Laboratory is a test facility for FEL research and novel accelerator technologies, providing high-quality electron bunches with charges up to 250 pC. Phase two of CLARA, which will bring the accelerator to its design energy (250 MeV) and repetition rate (100 Hz), is expected to begin commissioning in 2024. To maximise exploitation of the upgraded accelerator, a...
The future AMBER experiment aims to measure the inner structure and the excitation spectra of kaons with a high intensity kaon beam at the CERN secondary beam line M2. One way to identify the small fraction of kaons in the available beam is tagging with the help of differential Cherenkov detectors (CEDARs), whose detection efficiency depends critically on the beam parallelism. In the framework...
Modern linac-based free electron lasers (FEL) opened a new area of scientific research in physics, chemistry, biology and material sciences. In recent years laser plasma accelerator (LPA) technology has made great progress towards compact electron ‘GeV-energy scale’ accelerators. Combination of compact LPA accelerator with well-established technologies to build dedicated electron beam...
The ‘Laser-hybrid Accelerator for Radiobiological Applications’, LhARA*, facility is conceived to study the biological response to ionising radiation, specifically focussing upon the co-called ‘FLASH’ (>40 Gy/min) regime. A high repetition laser, directed at a thin target, will generate high intensity, ultra-short, particle bunches, at up to 15 MeV/u (and subsequent acceleration up to 127...
Electron Cyclotron Resonance Ion Sources (ECRIS) are commonly used as injectors in many accelerator laboratories and industries and therefore, pushing its limit towards very high charge state and intense ions for nuclear and elementary particle physics and low charge state ions for surface treatments & medical purposes. For these applications, several models of ECRIS were designed and...
JSPEC (JLab Simulation Package on Electron Cooling) is an open-source C++ program developed at Jefferson Lab, which simulates the evolution of the ion beam under the influence of both IBS and electron cooling effects. In this paper, we will report the latest updates to JSPEC. Firstly, we have added theoretical and numerical models that simulate the effect of the electron beam dispersion on...
The PERLE (Powerful Energy Recovery LINAC for Experiment) collaboration is developing a high power energy recuperation linac facility with three acceleration (up to 500 MeV) and three deceleration passes through two cryo-modules at an injection current of 20 mA. Here we present the lattice design of the first stage of this machine with one cryo-module that would demonstrate the six-passes...
In the next heavy ion runs at the LHC, the cleaning of the beam halo will rely on crystal collimation. A test system installed in the collimation cleaning insertion is being upgraded for the operational challenges of the ion runs. Therefore, it is crucial to experimentally test the performance of the newly installed crystal primary collimators. During a dedicated short Pb ion beam test in...
A CeB6 thermionic gun is presently operating for the X-ray free-electron laser (XFEL) facility SACLA. The gun emits high-intensity stable electron beams with a low-emittance of 0.6 µm, however, the emission lifetime of CeB6 cathode was unexpectedly limited to only one year or less at the SACLA injector. Recently, it was predicted by a particle tracking simulation and measurements that a cause...
We propose a linear accelerator concept for a Next Generation Nuclear Physics Accelerator Facility - a versatile User Facility with a wide variety and high availability of its instruments and beam time.
The concept is based on the simultaneous acceleration of light and heavy ion primary beams. It improves the utilization of the superconducting driver-accelerator capabilities and allows for...
A facility for the collision of muons offers a unique path to a compact lepton collider with an energy reach in the multi-TeV regime, well beyond the possibilities of conventional electron accelerators. However, due to the short lifetime of muons, the constraints for acceleration and collisions are very different. An extremely fast energy increase in combination with intense and ultra-short...
The FAST Injector at Fermilab has been the focus of a number of recent experimental efforts as 1) the driver of a novel FEL experiment, 2) as the injector for IOTA, and 3) as a test-bed for novel machine learning algorithms to reconstruct phase space measurements. Here we present our recent work to simulate the FAST injector and perform realistic comparisons of simulated beam distributions to...
Dalian Coherent Light Source (DCLS) is a free-electron laser (FEL) user facility. As a user facility, it is vital to provide the long-term stable FEL light, namely drift suppression. DCLS is a comprehensive integration of various devices, any key part of perturbation will result in drift of FEL lasing. Beam-based feedback (BBF) is an effective method to suppress the drift. This paper will...
Intra-beam scattering and other mechanisms can degrade the beam quality in the EIC Hadron Storage Ring. Strong hadron cooling will maintain the beam brightness and high luminosity during long collision experiments. An Energy Recovery Linac is used to deliver the high-current high-brightness electron beam for cooling. The best cooling rate is realized when the electron beam has low emittance,...
The ever-enriching beam application scenarios have put forward more demands on accelerators. With the research and application of multiple energy extraction technology in synchrotrons, how to extract multiple energy bunches in a shorter time has become the next problem to be solved, and it is expected to be applied in tumor radiotherapy. This paper provides three methods for generating short...
The vast majority of nuclear physics simulations are dependent on the National Nuclear Database, maintained at Brookhaven National Lab, and these in turn are all based on published experimental measurements. Even today, there are gaps in this database in low energy ranges, which can be filled even by older machines. In addition to the scientific output, these measurements provide a unique...
The high-energy upgrade of the Linac Coherent Light Source II (LCLS-II-HE) will extend the X-ray energy range up to 20 keV. The goal is to produce low emittance (0.1 mm∙mrad) electron bunches (100 pC/bunch) and accelerate 30 μA beams through the superconducting linac to 8 GeV. A low-frequency superconducting radio-frequency photo-injector (SRF-PI) will be a key aspect of the upgrade. An...
A new secondary beamline was recently installed in the MeV Test Area (MTA) with the objective of enhancing mu+/mu- production by factors of 3/8 by using a tungsten target versus the conventional graphite production target using the 400 MeV Fermilab proton Linac beam. Ultra-low energy muon beams can support world-class physics experiments for fundamental muon measurements, sensitive searches...
The photon flux resulting from a high energy electron beam's interaction with a target, such as in the upcoming FACET-II experiments at SLAC National Accelerator Laboratory, should yield, through its spectral and angular characteristics, information about the electron beam's underlying dynamics at the interaction point.
This project utilizes data from simulated plasma wakefield...
Fourth generation light sources require high brightness electron beams. To achieve this a cathode with a high quantum efficiency and low intrinsic emittance is required while also being robust with a long lifetime and low dark current. Alkali-metal photocathodes have the potential to fulfil these requirements and, as such, are an important area of research for the accelerator physics...
The China Spallation Neutron Source (CSNS) has been operated with 100kW beam power on target since 2020. The Linac consists of an H- ion source, a low-energy beam transport line (LEBT), a 3 MeV Radio Frequency Quadrupole (RFQ), a Medium Energy Beam Transport line (MEBT) and a Drift Tube Linear (DTL) accelerator to boost the beam energy to 80 MeV with a beam intensity of 10 mA. A power upgrade...
Cavity-based XFEL, or CBXFEL, is a future highly-coherent photon source under construction at LCLS. In the first phase of the CBXFEL project, we will demonstrate the regenerative amplifier mode of operation with 7 LCLS Hard X-ray Undulators (HXUs). In this paper, we report on the recent measurement of the FEL gain in 7 LCLS HXUs, and hard x-ray self-seeding (HXRSS) under e-beam conditions...
Resistive oven technique is used to inject vapours of metallic species in plasma traps, where plasma sustained by the electron cyclotron resonance (ECR) mechanism provides step-wise ionisation of neutral metals, producing charged ion beams for accelerators. We present a numerical survey of metallic species suitable for oven injection in ECR ion sources to explore neutrals diffusion and...
The photocathodes used as electron sources in high-performance electron accelerators today are largely one of only a handful of materials. While there has been an increased understanding of the properties of the electron beams produced by these cathodes, there has been little change in the overall selection of materials used at accelerator facilities. In fact, nearly all of the photocathodes...
Hollow-core dielectric Electromagnetic Band Gap (EBG) microstructures powered by lasers represent a new and promising area of accelerator research since, thanks to the short optical wavelength and to the dielectric's high damage threshold greater accelerating gradients, with respect to the metallic counterparts, can be achieved.
In this paper, we present MeV-scale beam-dynamics simulations...
The electromagnetic Particle-In-Cell (PIC) code WarpX has been developed by the U.S. Department of Energy’s Exascale Computing Project, in collaboration with international partners, toward the modeling of plasma accelerators on Exascale Supercomputers. We will give an overview of the code and its latest features, such as collision and QED physics modules. We will also report on the latest...
Short bunches, high current and multiple linac pass are all characteristics of Energy Recovery Linacs (ERLs), which may result in collective effects. They in turn, may affect the beam, degrading its quality, or even yield to instabilities causing a beam loss. To study and mitigate these effects one needs a numerical simulation code, that can take into account both the collective effects, as...
High-quality electron beams are critical for generation of
intense X-ray pulses from free electron lasers. It was proposed
that complex thin films and heterostructures with semiconductor
photoemissive layers may be used in photocathodes to produce
electron beams with better quality. New developments in material
science allow designing alkali-antimonide photocathodes with
specific...
Modern free-electron laser (FEL) facilities are designed to simultaneously serve multiple undulator lines to pro-vide x-ray pulses with high peak power and tunable wavelengths. To satisfy different scientific demands, it is preferred to make the separate undulator lines work under different FEL schemes, such as the self-amplified sponta-neous emission (SASE) scheme and the echo-enabled...
We demonstrate a simple method to generate two-color or multi-color soft x-ray FEL pulses. This method mainly uses a chirped electron beam working together with an EEHG alike modulator and chicane setup to produce wide electron beam bunch train. And this bunch train can be used to generate multi-color FEL pulses. By tuning the configurations and parameters of the method, we can easily adjust...
The ongoing Plasma-driven Attosecond X-ray source experiment (PAX) at FACET-II aims to produce coherent soft X-ray pulses of attosecond duration using a Plasma Wakefield Accelerator [1]. These kinds of X-ray pulses can be used to study chemical processes where attosecond-scale electron motion is important. For this first stage of the experiment, PAX plans to demonstrate that <100 nm bunch...
Time-varying fluctuations of the intensity sharing between the islands and the core of the beam extracted via the CERN Proton Synchrotron (PS) Multi-Turn Extraction are the main effects that require manual adjustment for this beam type. To mitigate this, the application of an online controller is explored to further enhance both operational autonomy of the accelerator and physics performance....
Unprecedented electron beam brightness can potentially be achieved by exploiting high gradients in cryo-cooled RF cavities functionalized with high QE semiconductor photocathode materials. However, strong electric fields and thermal stresses from associated emission currents could potentially affect material stability, leading to breakdown events which may shorten device lifetime or degrade...
XiPAF (Xi'an 200MeV proton application Facility) synchrotron is using H^- stripping injection and phase space painting scheme. With the demand of more particle species for single event effect study, XiPAF synchrotron has been upgraded to multiturn injection from stripping injection, the injection system must be redesigned. This paper report XiPAF synchrotron multiturn injection scheme, a...
The K12 beam line and NA62 experiment in the North Area at CERN in beam dump mode exploits the interactions of 400 GeV protons with a movable dump-collimator, the so-called XTAX. Such interactions are theorised to generate potential light dark matter candidates such as the axion. Any rare process search requires precise knowledge and experimental reduction of the predominant muon background. A...
A new, high-efficiency source of a Muonium beam will be useful for fundamental muon measurements, sensitive searches for symmetry violation, and precision tests of theory. In the PIP-II era, Fermilab has the potential to provide the world's highest-intensity Muonium beam, by a considerable margin. Moreover, with the advent of a muon beam at Fermilab's existing 400 MeV linac, the necessary R&D...
Gabor-lens 2000 (GL2000) is an hadron optic device which confines a 2m long electron cloud. This opens up new possibilities in research with very long confined static electron ensembles. Due to the optimization of technical design it was possible to successfully complete the conditioning process creating a stable confinement of electrons. Also, the diagnostic tools were extended and the...
State-of-the-art spin-polarized photo-electron sources use GaAs-based photocathodes to provide electron beams with high degrees of spin-polarization. Such photo-guns are required to operate with both quantum efficiency and cathode lifetime as high as possible in order to meet the requirements of high-current applications such as energy-recovery linacs and colliders. Both quantum efficiency and...
A new project, NEWGAIN (NEW GAnil Injector), is under development at GANIL, and aims to build a second injector for heavier beams with A/q up to 7, as an extension of the SPIRAL2 accelerator. With this upgrade, SPIRAL2 will provide high intensity beams, from proton to uranium, thus increasing GANIL international competitiveness both in fundamental science and associated applications.
This...
Noise and density fluctuations in relativistic electron bunches, accelerated in a linac, are of critical importance to various Coherent Electron Cooling (CEC) concepts as well as to free-electron lasers (FELs). For CEC, the beam noise results in additional diffusion that counteracts cooling. In SASE FELs, a microbunching instability starts from the initial noise in the beam and eventually...
Recent studies by Dejan Trbojevic have confirmed that Non-Scaling Fixed Field Accelerators (NS-FFAs) can have their tune dependence on momentum flattened by adding non-linear components to the magnet fields, although not necessarily for an unlimited momentum range. This paper presents such a cell suitable for the proposed 3-12MeV FETS-FFA proton R&D ring at RAL.
The nonlinear magnetic field...
Electron beams serve many important roles from free electron lasers to medical imaging. Every time beam brightness is improved, a wide variety of fields take another step forward. Nanopatterned field emission cathodes serve as an excellent opportunity to continue to push the envelope on extreme high brightness beams. Their fabrication is thus of crucial importance to this objective. In the...
We have proposed a new method to generate coherent soft X-ray free electron lasers by the reverse-taper enhanced cascade echo-enabled harmonic generation. The method is based on the typical EEHG technique and a latter harmonic undulator section to lase the harmonic of the EEHG output. By using the reverse-tapered undulator at the EEHG undulator, an optimised FEL will be generate at the second stage.
The LANSCE accelerator facility has been in operation for 50 years performing important scientific support for national security. The unique feature of the LANSCE accelerator facility is multi-beam operation, delivering beams to five experimental areas. To reduce long-term operational risks and to realize future beam performance goals in support of the laboratory missions, we develop a novel...
Development of advanced intense and reliable sources of charged particle beams is a direction within accelerator physics on its own right. By changing the temperature of Lithium Tantalate (LiTaO3) single crystal at moderate vacuum conditions leads to generation of strong electric field. The uncompensated polarization during the heating or cooling of the crystal causes the ejection of electrons...
In the J-PARC Main Ring, a project to upgrade the beam power to 1.3 MW is currently underway. The most important issues in realizing such a high-power beam operation are controlling and minimizing beam loss, which are essential for sustainable beam operation allowing hands-on maintenance. In this paper, we report on our recent efforts to understand the mechanism of beam loss and to reduce it.
Dielectric-lined waveguides have been extensively studied to potentially support high-gradient acceleration in beam-driven dielectric wakefield acceleration (DWFA) and beam manipulations. In this paper, we investigate the beam dynamics in the alternating-symmetry slab-based dielectric wakefield accelerator proposed and discussed in Ref.[1]. We use the first principle electromagnetic...
The realization of a plasma based user facility on the model of EuPRAXIA@SPARC_LAB requires to design a working point for the operation that allows to get an high accelerating gradient preserving a low emittance and low energy spread of the accelerated beam. Such beam is supposed to pilot a soft x-ray free electron laser, a device with very challenging requirements in terms of brightness and...
Generation of attosecond XFEL pulses has drawn great attention in a wide range of research fields over the past decade. Adaptation and combination of state-of-the-art FEL techniques have led to advanced working schemes capable of producing the required ultra-short X-ray pulses. At the European XFEL, an R&D project, the AttoSecond Pulses with eSASE and Chirp-Taper schemes (ASPECT), has been...
The Mainz Energy-recovering Superconducting Accelerator (MESA), currently under construction at the Johannes Gutenberg University (JGU) in Mainz, will offer two modes of operation, one of which is an energy-recovering (ER) mode in order to deliver electron beams of up to 155 MeV to two experiments. As an ERL, MESA, with it's high brightness electron beam, is a promising accelerator for...
A THz free electron laser (FEL) prototype has been developed at the Photo Injector Test Facility at DESY in Zeuthen (PITZ) for obtaining high intensity radiation for THz-pump-X-ray-probe experiments at the European XFEL. In this development, a magnetic chicane was recently installed to optimize the THz FEL performance. The aim of this study was to investigate the beam dynamics in the chicane...
The relativistic interaction of short pulsed lasers or electrons with plasma has recently led to the birth of a new generation of femtosecond X-ray sources. Radiations with properties similar to those that can be observed from a wiggler or undulator, can be generated by the oscillations induced in the exited plasma by electrons (PWFA) or by lasers (LWFA), making plasma an interesting medium...
This work is focused on the anomalous skin effect in copper and how it affects the efficiency of copper-cavities in the temperature range 40-50 K. The quality factor Q of three coaxial cavities was measured over the temperature range from 10 K to room temperature in the experiment. The three coaxial cavities have the same structure, but different lengths, which correspond to resonant...
Protection of free-electron sources has been technically challenging due to lack of materials that transmit electrons while preventing corrosive gas molecules. Two-dimensional (2D) materials uniquely possess both of required properties. Here, we report three orders of magnitude increase in operation pressure and factor of two to four enhancement in the lifetime of high quantum efficiency (QE)...
CRYRING@ESR is a low-energy heavy-ion storage ring recently recommissioned at GSI, Darmstadt, as part of the FAIR project. With its standard working point lying on the lowest-order difference resonance, the ring contains a compensation solenoid to counter coupling of betatron motion introduced by the electron cooler magnetic field. That solenoid largely occupies one of the drift sections of...
The Los Alamos Neutron Science Center (LANSCE) is a very flexible H-/H+ 800-MeV proton linear accelerator and storage ring that serves five distinct user facilities in support of LANL’s national security mission and commercial applications. It is unique because of the intensity and energy spectrum of the neutrons produced. The Isotope Production Facility (IPF) operates using an H+ beam line at...
This poster will report the progress on optical optimization of Cs2Te photocathodes using simulations and preliminary experimental results. Thin film semiconductor photocathodes are often used in high brightness electron sources. These sources are particularly bright when the cathodes are operated “near threshold”, i.e., with a laser energy close to the sum of the band gap and electron...
The MYRRHA project (Multi-purpose hYbrid Re-search Reactor for High-tech Applications) is a planned accelerator-driven system (ADS) that will be realised at Mol in Belgium and will demonstrate the feasibility of transmutation of radioactive waste on an industrial scale.
The planned accelerator, which is to provide the 600 MeV proton beam, consists of a normal-conducting 17 MeV injector that...
As part of the EuPRAXIA project[1], the objective of the PALLAS project is to produce an electron beam at 200 MeV, 30 pC with less than 5% energy spread and lower than 2μm normalised emittance using the IJCLAB-LaseriX laser driver at 10 Hz, 1.5 J and 35 fs. Based on available publications[2,3], we propose a two-chamber gas plasma target with a dopant...
For storage-ring-based free-electron lasers (FELs), prebunching via echo-enabled harmonic generation (EEHG) is an efficient way to reduce the radiator length and improve the longitudinal coherence as well as output stability. We propose a conceptual design, which uses two straight sections of a synchrotron to seed coherent soft X-ray emission. This scheme requires no change of the storage ring...
Currently 26 RF stations are in operation at the European X-ray Free Electron Laser (XFEL) and all RF stations can deliver sufficient power to support 600 µs beam pulse with an energy up to 17 GeV. These beam parameters require a power consumption of about 4.9 MW for high-power RF. Of course, the simplest way to save power is to reduce the XFEL repetition rate, but with some additional work...
Xi'an Proton Application Facility (XiPAF) synchrotron provides 10~200MeV proton beam for the experimental simulation of the space radiation environment. Due to the space charge effect, the slow extraction of 10 MeV proton beam is a work full of challenges. In a past experiment, the total extraction efficiency was over 65% with 4.5 ~ 6.5×1010 protons stored before extraction but decreased to...
The JEDI experiment is dedicated to the search for the electric dipole moment (EDM) of charged particles using storage rings, which can be a very sensitive probe of physics beyond the Standard Model. In order to reach the highest possible sensitivity, a fundamental parameter to be optimized is the Spin Coherence Time (SCT), i.e., the time interval within which the particles of the stored beam...
In this proceeding, we will examine the designs of cavity-based XFEL (CBXFEL) and X-ray laser oscillator (XLO) currently under construction at SLAC. We will point out the possible improvements in the optical design, and propose new schemes. We especially focus of rectangular and bow-tie geometries.
A THz SASE FEL is currently under operation at the Photo Injector Test facility at DESY in Zeuthen (PITZ) as a prototype THz source for pump-probe experiments at the European XFEL.This prototype should provide tunable (3-5 THz) narrowband THz radiation with THz pulse energies up to several hundred μJ from 17-20MeV electron beams with a beam charge of several nC and a peak current up to 200 A...
MeV-ultrafast electron diffraction (MeV-UED) has enabled broad scientific opportunities for the studies of structural dynamics, ultrafast chemical processes and coupling of electronic and atomic motions in a variety of gas, liquid and solid state systems. The growing demand of future scientific needs calls for relativistic electron probes with ultra-short bunch length(10 fs) and ultra-low...
Cooling of secondary beams is often critical to accelerator based nuclear and sub-nuclear physics, with beams ranging from positrons e+ to muons μ+/- to hadrons (for the respective collider facilities) to exotic nuclei ions (like 132Sn1+) as in the SPES (Selective Production of Exotic Species) project at LNL. A prototype of a radiofrequency quadrupole (RFQ) cooler (RFQC) was developed at LNL...
Particle-in-cell simulation plays an important role in optimization of today’s plasma-based acceleration research and experiments. Due to many variables involved, the computational cost is usually very high, especially when the experiment includes several different beams, e.g., the AWAKE experiment. AWAKE Run2 uses the proton bunch to drive plasma wakefield and accelerate electron bunch in 10...
This paper proposes a new coupling slots design for the Pi-Mode structure high-frequency cavity in the China Spallation Neutron Source (CSNS) Phase II. Through simulation calculations and experimental verification, it was found that the new coupling slots design significantly improves the Q value and transmission efficiency of the high-frequency cavity. This study is of great significance...
The problem of standing wave formation by superposing two counter-propagating whistler waves in
an overdense plasma, studied recently by Sano et al (2019 Phys. Rev. E 100, 053 205 and 2020 Phys. Rev.
E 101, 013 206), has been revisited in the relativistic limit. A detailed theory along with simulation has
been performed to study the standing wave formation in the interaction of two counter...
2022 has been a performance consolidation year for the Low Energy Ion Ring (LEIR) at CERN that demonstrated its capability of delivering the target beam parameters required for high luminosity production in the LHC in a reproducible and reliable way. The main steps that have led to the high performance reach of this beam, together with the machine stability improvements deployed, are detailed...
The cryocooled DC electron gun at Arizona State University (ASU) is the first electron gun built to implement single-crystal, ordered surface and epitaxially grown photocathodes to produce cold and dense electron beams at the source. These high brightness electron sources are extremely desirable for ultrafast electron applications such as Xray Free Electron Lasers (XFELs), Ultrafast Electron...
The {2, 2} Danilov distribution is self-consistent — it is a Vlasov equilibrium distribution that produces linear space charge forces. Additionally, the distribution has zero (four-dimensional) transverse emittance. Thus the Danilov distribution may be of use for overcoming space charge limitations at high intensities, increasing collider luminosity, or pushing the limits of transverse bunch...
INFN LASA photocathode lab develops and produces films that are used in high brightness photoinjectors. Besides the long-time and still on-going experience on Cs2Te, recently we have restarted an activity on alkali-antimonide films, sensitive to visible light, exploring the possibility of their stable operation in CW machine. We report in this paper the recent results obtained both on the...
The ARES linac at DESY (Deutsches Elektronen-Synchrotron) is a dedicated accelerator research and development facility for advanced accelerator technologies and applications, including high gradient accelerating schemes, high-resolution diagnostics and medical applications. It provides ultra-short, high quality electron beams with charges between a few femtocoulombs and a few hundred...
The photoinjectors of FLASH at DESY (Hamburg, Germany) and the European XFEL are operated by laser driven RF-guns. In both facilities cesium telluride (Cs$_2$Te) photocathodes are successfully used since several years. We present recent data on the lifetime and quantum efficiency (QE) of the current photocathode at FLASH #105.2, operated before and after a long shutdown. In addition, data for...
As accelerators and electron microscopes become more advancement, high-performance photocathodes are required. In particular, CsK2Sb photocathode is of interest because of its low emittance, excitability in visible light, and high quantum efficiency (QE). On the other hand, it has drawbacks such as weak structure, limited operating vacuum pressure, and short lifetime with time or charge. To...
Integrating the advances made in photonics with efficient electron emitters can result in the development of next generation photocathodes for various accelerator applications.
In such photonics-integrated photocathodes, light can be directed using waveguides and other photonic components on the substrate underneath a thin (<100 nm) photoemissive film to generate electron emission from...
The proposed Shenzhen Superconducting Soft X-Ray Free-electron Laser (S3FEL) aims at generating FEL pulses between 1nm and 30nm. At phase-I, two undulator beamlines work at EEHG principle. The shortest wavelength is about 2.3nm at a harmonic of 104. However, the various three-dimensional effects of beam can smear out the fine structure in the longitudinal phase space for the EEHG, especially...
The proposed Shenzhen Superconducting Soft X-Ray Free-electron Laser (S3FEL) aims at generating FEL pulses whose wavelengths ranges from 1 to 30 nm. As part of the first phase of S3FEL, two undulator beamlines working under SASE operation mode is planned. The two beamlines generate FEL pulses with wavelengths ranging from 1 to 3 nm and 2.3 to 15 nm, respectively. The physical designs and the...
Shenzhen Superconducting Soft X-Ray Free-electron Laser (S3FEL) is a newly proposed high repetition-rate X-ray FEL facility. It will be located at Guangming Science City in Shenzhen with a total length of 1.7 km. The electron beam is generated from a VHF photocathode gun and accelerated to 2.5 GeV through a superconducting RF linac. At initial phase, it is planned to build four undulator lines...
A 35MeV/2 mA S-band electron linear accelerator used to interact with solid targets to generate neutrons, gamma rays, and X-rays has been proposed to provide a scientific research platform for nuclear energy development, material development, biomedicine, deep space exploration besides other industrial applications. The accelerator has a three-stage accelerating structure, after the...
The CERN-wide coordination of the programmed stops requires a tool to centralize and collect all the activities at a macroscopic scale. It includes the activities foreseen during Long Shutdowns (LS) and Year End Technical Stops (YETS).
The CERN tool named PLAN centralises all the activities foreseen by the Groups, to have a global strategic view, assessing priorities across CERN. Thanks to...
In 2021, the Italian Institute for Nuclear Physics (INFN) was awarded the project for installing, testing and commissioning the energy upgrade of the Southern European Thomson back-scattering source for Applied Research (STAR) which is currently installed at the University of Calabria (UniCal). The STAR high-energy Linac, STAR-HEL, consists in a layout comprising RF accelerating structures...
Betatron radiation produced in the plasma acceleration process could be used as seed for Free Electron Laser (FEL). A broad band radiation in the X-ray spectral region is produced by the strong transverse electron oscillation in the plasma channel driven by particle or laser wake field acceleration. Selecting the betatron radiation wavelength matched with FEL resonance, with proper...
To generate high-current B+ ion beams for ion implantation, a hybrid ion source that combines electron cyclotron resonance and thermal surface ionization, which is called a high-temperature surface microwave source (HSMS), is under development. A high-temperature hot surface (2000℃) and microwave heating are the essential components of an HSMS to produce high-energy electrons for the B+...
Particle beams with highly asymmetric emittance ratios are employed at accelerator facilities and are expected at the interaction point of high energy colliders. These asymmetric beams can be used to drive high gradient wakefields in plasmas. In plasma, the high aspect ratio of the drive beam can create a transversely elliptical blowout cavity and the asymmetry in the ion column creates...
Plasma-based accelerators enable compact acceleration of beams to high energy and are being explored as a potential technology for future linear colliders. Conventional linear colliders require damping rings to generate the required beam emittance for particle physics applications. We present and discuss a plasma-based linear radiation damping system that allows cooling of ultrashort bunches...
Cavity based X-ray free-electron lasers (CBXFEL) are next generation X-ray sources promising radiation with full three-dimensional coherence, nearly constant pulse to pulse stability and more than an order of magnitude higher spectral flux compared to SASE FELs. However, especially for the low gain X-ray free-electron laser oscillator (XFELO), the outcoupling of the radiation stored inside the...
The RAON ultra-low energy experiment team decided that the first experiment was to accelerate the proton 70 MeV using a cyclotron and collide with the SiC target to generate a radioactive isotope beam. Before this experiment, a preliminary experiment was conducted to confirm the exact location and shape of the proton beam before directly colliding with the target to generate a lot of radiation...
We are building a new infrared Free Electron Laser (FEL) facility in China that will produce infrared laser covering the spectral range from 2.5 um to 200 um. It is made up of two oscillators generating middle infrared and far infrared laser respectively, which are driven by a single RF linear accelerator (linac) with a tunable beam energy from 12 MeV to 60 MeV. According to the requirement of...
Two-beam acceleration (TBA) in Terahertz (THz) regime is the natural extension of Gigahertz TBA pursued in Structure Wakefield Acceleration Community. Recently proposed CSR-free shaping technique using deflecting cavities showed the feasibility of generating a high-charge (~1 nC per bunch) bunch train compatible with THz frequency. Wakefield from THz structure with such a h high-charge bunch...
There are two accelerator based infrared light sources in Kyoto University Free-Electron Laser (FEL) facility. One is a mid-infrared FEL covering the wavelength range from 3.4 to 26 micro-m driven by 40-MeV multi-bunch electron beams supplied from an S-band RF gun and an S-band linac. The other is a coherent undulator radiation* covering the wavelength range from 0.1 to 0.6 THz driven by...
We study ultrafast laser surface nanopatterning as an alternative to improve the photo-emissive properties of metallic photocathodes. By tailoring the physical dimensions of these surface nanostructures, one can localize the optical field intensity and exploit plasmonic effects occurring in such nanostructures. As a result, this surface nanopatterning technique can become a great tool for...
Self-seeding mode is the one of the FEL baselines at the SHINE, which has been used successfully at the LCLS, SACLA, PAL-XFEL and European-XFEL facilities. Both soft and hard X-ray self-seeding are adopted for the wide range of fully coherent X-ray spectrum coverage. Accordingly, the grating monochromator and crystal monochromator are the critical parts of the x-ray self-seeding. At the SHINE...
The new C-Band RF gun, developed in the context of the European I.FAST project has been realized. It is a 2.5 cell standing wave cavity with a four port mode launcher, designed to operate with short rf pulses (300 ns) and cathode peak field larger than 160 MV/m. In the paper we present the realization procedure and the results of the vacuum and low power RF test. The gun is now ready for the...
At its restart after a major shutdown in 2029, the LHC will see its interaction regions upgraded by the installation of the HL-LHC equipment, with new Nb3Sn triplets and cold powering system, crab-cavities for crossing angle compensation and luminosity levelling, an upgraded collimation system, and fully remote alignment for the final focusing region. In the following operational runs, the LHC...
Velocity bunching, sometimes called rectilinear rf bunch compression, is a common technique to generate femtosecond MeV electron bunches from a photoinjector system. Such ultrashort beam can be used to generate coherent THz radiations, in particular, coherent undulator radiation (CUR). However, beam properties such as beamsize, transverse emittance, bunch length and energy spread after bunch...
n recent years the interest in high intensity, short-pulse coherent THz radi-
ation for non-linear experimental research and applications grew with upcoming
high intensity lasers. In contrast to lasers, accelerators provide free electrons
for which emission properties can be tailored to the demand at typically much
higher repetition rates than high-intensity lasers can provide. Efforts are...
A high-power proton linac at KOMAC uses a drift tube linac structure to accelerate protons up to 100 MeV. Currently, a total of 148 drift tubes with electromagnetic quadrupoles are used in DTL sections for accelerating protons from 3 MeV to 20 MeV. A drift tube based on a permanent magnet quadrupole has been designed and prototyped to replace the EMQ-based drift tube to enhance the DTL...
The Electron-Ion Collider (EIC) incorporates beam crabbing to recover geometric luminosity loss from the nonzero crossing angle at the interaction point (IP). It is well-known that crab cavity imperfections can cause growth of colliding beam emittances, thus degrading collider performance. Here we report a particle tracking study to quantify parts of these effects.
cERL in KEK is a test accelerator for development works of technologies related to Energy Recovery Linac (ERL) and CW-Superconducting accelerators. It can produce a low emittance and short bunch beam at a high repetition rate. This feature is suitable for producing a high average power terahertz (THz) coherent radiation. We have been developing a THz source based on Coherent Diffraction...
In accordance with the program of NSC KIPT Subcritical Neutron Source physical start up that was approved by State Nuclear Regulator the basic measurement method of reactivity and keff is an area ratio measuring method. In the method, the neutron response of the SCA on the electron beam pulse is measuring. For on-line monitoring of the system reactivity the neutron flux to beam current ratio...
A shared ambition in the R&D of future light sources is designing and constructing an ideal free-electron laser (FEL). Such a machine will produce tunable, multicolor, near transform-limited pulses, with a controlled delay, and fully coherent beams with precisely adjustable phase profiles enabling state-of-the-art measurements and studies of femtosecond dynamic processes with high elemental...
Plasma accelerators are emerging as formidable and innovative technology for the creation of table-top devices thanks to the possibility to sustain several GV/m accelerating gradients at normal conducting temperature. Among others, the particle-driven configuration has been successfully tested at the SPARC_LAB test facility also demonstrating the emission of plasma-based FEL radiation in SASE...
Coherent, wide-tunable frequency and high intensity terahertz (THz) source is under preparation at the Shanghai Soft X-ray free-electron laser facility (SXFEL). The strong field THz radiation from 0.1 to 5 THz is generated by coherent transition radiation (CTR) when compressed electron bunches pass through the metal foil. In addition, the electron bunches modulated by frequency beating light...
The 3 GeV rapid cycling synchrotron (RCS) at the Japan Proton Accelerator Research Complex (J-PARC) provides more than 800 kW beams to the Material and Life Science Facility (MLF) and Main Ring (MR). We have been continuing a beam study to achieve 1-MW, design power operation. In addition, we have also improved and maintained the accelerator components to establish a stable operation. This...
FLASH, the Free electron LASer in Hamburg is currently undergoing a substantial refurbishment and upgrade project (FLASH2020+). A major stage was the 9 month shutdown in 2021/22. During this shutdown key components of the injector/linac where inserted, moved, rebuild or upgraded to enable the efficient and reliable preparation of electron...
Future proton superconducting RF (SRF) linacs used as accelerator driven systems (ADS) must achieve high reliability and availability to meet the challenging parameters for applications in medical treatment, nuclear waste reduction, and nuclear power generation. What SRF innovations and advanced concepts are needed? To answer this question, a case study of the past, current, and possible...
Xi 'an 200 MeV Proton Application Facility (XiPAF) will be upgraded to proton and heavy ion synchrotron recent-ly. In order to ensure the enough life of heavy ion beam, the synchrotron requires ultra-high vacuum, and the de-signed static vacuum is better than 5×10-10 Pa. In order to place enough vacuum pumps in the synchrotron, the circumference of the synchrotron was increased from 30.9m to...
The Radio Frequency Quadrupole (RFQ) for the High-Intensity Photon Injector (IPHI) project has been designed and manufactured in the early 2000s. It is now operating at CEA Saclay since 2016 and accelerates a 100-mA continuous beam up to 3 MeV. It is a 6-meter-long, 3 segments vane RFQ, with 352.2 MHz operation frequency and non-constant voltage profile. From this RFQ, a lot of experience has...
We review the theory of optical klystrons with SASE FEL applications in mind. Previous theories miss terms in the power gain factor that cannot be neglected, and we illustrate differences between the previously known analytical expressions, new ones discussed here, and numerical calculations. We then consider the use of optical klystrons for electron energy-spread and radiation coherence-time...
The Linear IFMIF Prototype Accelerator (LIPAc) is designed to accelerate 125mA of deuteron beam to 9MeV in continuous wave (CW). The superconductive RF Linac has not yet been installed and the final accelerating stage now under commissioning is the RFQ. This system has been designed and developed by INFN (Italy) before installation in QST (Japan). The RFQ is the longest in the World with its...
The Cyrcé facility of IPHC in Strasbourg operates a TR24 cyclotron to produce medical isotopes, lead radiobiology programs and test detectors.
A RF kicker has been developed in order to discard one beam bunch over two to get a rate close to 40MHz. An RF voltage at a quarter of the cyclotron frequency applied to a deflector in the injection line allows to reach that goal. The 30keV DC beam...
The recent layout of the Jülich High Brilliance Neutron Source (HBS) driver linac is based on short crossbar H-mode (CH) cavities operated at a fixed synchronous phase. In the last decades the computing power for the development of linacs, available to physicists and engineers, has been increased drastically. This also enabled the accelerator community to finally carry out the required R&D to...
Accelerators having large electric field gradients are the need of the hour for building future electron or proton colliders. Plasma wakefield accelerators using short electron or proton bunches can solve the problem of achieving large amplitude plasma wake. In PWFA, we have witnessed that, large amplitude wakefields generated by such mechanisms have both transverse and longitudinal components...
Flat beams are preferred at high energies due to their ability to achieve high intensity and luminosity, as one of the transverse emittances is smaller. However, at low energies, collective effect such as space charge becomes dominant in the smaller dimension. Intra-beam scattering(IBS) effect is dominant when local beam density is high, from medium to high energies. Circular mode beams, which...
IAEC/SNRC (Israel) is constructing an accelerator facility, SARAF, for neutron production. It is based on a linac accelerating 5 mA CW deuteron and proton beam up to 40 MeV. As a first phase, IAEC constructed and operated a linac (SARAF Phase I), from which remains an ECR ion source, a Low-Energy Beam Transport (LEBT) line and a 4-rod RFQ. Since 2015, IAEC and CEA (France) are collaborating in...
As Compton X-ray and gamma-ray sources become more prevalent, to understand their performance in a precise way it becomes important to be able to compute the distribution of scattered photons precisely. An ideal model would: (1) include the full Compton effect frequency relations between incident and scattered photons, (2) allow the field strength to be large enough that nonlinear effects are...
The Scheduling Tool Project (ST Project) is in charge of ensuring the scheduling and coordination of CERN accelerator programmed stops and facilities installation managed within the Accelerator Coordination and Engineering (ACE) Group, inside the Engineering Department (EN) at CERN, since 2019. The scheduling tools should consider all the activities, that take place in large facilities,...
FLASH, the Free-Electron Laser in Hamburg, houses an experimental beam line for the study of seeding called Xseed. For the upcoming realization of a seeded FEL in the scope of the FLASH2020+ project, these components offer a unique possibility to study hardware, procedures and software for a future seeded operation. In this contribution we give an overview of the FLASH accelerator, the...
ECR ion sources produce ion beams with an intensity proportional to the heating frequency. SEISM (Sixty gigahErtz Ion Source using Megawatt magnets) is a unique source operating at the record frequency of $60~GHz$ thanks to a gyrotron producing high intensity HF pulse (up to $300~kW$). The prototype is based on a simple magnetic geometry, the cusp, using polyhelix coils (developed with the...
A relativistic, charged particle bunch propagating in plasma is subject to various instabilities. When the bunch is much longer than the cold plasma skin depth, it is subject to the self-modulation instability (SMI). This instability is routinely observed in the AWAKE experiment with narrow (200microns), long (7cm) proton bunches**. Bunches wider than the skin depth are subject to the...
Externally seeded free electron lasers (FELs) offer fully coherent and stable FEL radiation in the soft x-ray regime. While electron bunches of superconducting-based FELs are available at MHz repetition rates, seeded radiation is limited by the repetition rate of the seed laser used in the process. Combining standard seeding schemes with an optical klystron is a simple and promising trick to...
With the FERMI2.0 upgrade plan FERMI is planning a major upgrade of the two FEL lines and the linac in order to extend the tuning range toward 2 nm in the fundamental and with full polarization control. The shortest wavelength range will be reach with a two stage FEL relying on a first Echo Enabled Harmonic Generation operating at harmonic close to 30 to convert the UV seed laser wavelength to...
Extraction by third order resonance in low-energy stage will suffer from strong space charge effect, high beam emittance, high power ripple and so on. Low-energy slow extraction at 10 MeV has been explored theoretically and experimentally at synchrotron of Xi'an Proton Application Facility (XiPAF), which is a compact synchrotron with injection energy of 7 MeV and extraction energy up to 230...
Different from the high Q value of ferrite cavity, the Q value of magnetic alloy cavity in CSNS RCS is only about 1.25, the frequency band of impedance is wide, and the beam loading effects is strong. Based on the impedance measurement results, the influence of the beam load effects on the longitudinal distribution of the magnetic alloy cavity in CSNS RCS is studied by simulation, and the...
We propose a simulation model of the field enhancement and quantum efficiency (QE) increase of metallic surfaces as a result of a surface nanostructuring. In the framework of photoinjector facilities for electron accelerators at CERN, achieving optimal nanostructuring parameters may become a significant asset. The presence of a well-designed periodic surface topography can give rise to...
One of the key aspects to provide on chip acceleration in Dielectric Laser Accelerators (DLA) from tens of keV up to MeV energies is the phase velocity tapering.
This paper presents the simulated performance of sub-relativistic structures, based on tapered slot waveguides. We engineered channel/defect modification in order to obtain a variable phase velocity matched to the increasing velocity...
At Pohang Accelerator Laboratory X-ray Free-Electron Laser (PAL-XFEL), the scheme for generating attosecond XFEL pulse at soft X-ray undulator line is developing. Enhanced Self-Amplified Spontaneous Emission (E-SASE) method with external laser pulse is adopted to induce the current spike in the electron beam and generate attosecond XFEL pulse. E-SASE section consists of the wiggler and the...
Externally seeded high-gain free electron lasers (FELs) are capable of providing fully coherent radiation with high shot-to-shot stability at wavelengths down to the soft X-ray range.
However, present seed laser sources are not suitable for the generation of short wavelength FEL radiation at high repetition rates. As a result, such setups have been unable to make use of the full repetition...
In many advanced accelerator facilities such as e+e--linear colliders and high gain free electron lasers, magnetic bunch compressors are often used for enhancement of beam brightness. However, the energy chirp (correlated energy spread) introduced into the beam by the chirper linac remained after bunch compression is undesirable in some applications. In this report, we present our study of a...
Plasma wakefield acceleration (PWFA) is a method for accelerating charged particles using large electric fields sustained by plasma waves (up to hundreds of GV m−1) for the accelerating longitudinal fields. In this project, we will evaluate the impact of perturbations on basic particle motion. These perturbations are affected by any number of terms of the equations of motion. The most...
In this study we investigate simulation results for a virtual diagnostics concept that is planned for the SASE1 beamline at the European XFEL. These virtual diagnostics will be used to predict photon beam properties like pointing and divergence. We first use the GENESIS simulation framework to compute different lasing conditions in the undulator beamline, and then use Artificial Neural...
The Laser Ion Source (LIS) can easily produce high charge state and high intensity ion beams, especially the refractory metallic ion beams, so it is a promising candidate as an ion source for heavy ion cancer therapy facilities and a future accelerator complex, where a pulsed ultra-intense and high-charged heavy ion beam is required. Due to the capability of LIS to produce high-brightness ion...
J-PARC Main Ring (MR) delivers slow extracted 30 GeV proton beam to the Hadron Experimenal Facility using third-order resonance.
Various particle and nuclear physics experiments are being conducted there, and one of the important properties required for the proton beam is the flatness of the time structure of the extracted beam (spill structure).
At J-PARC MR, the large current ripples in...
SOLARIS injector LINAC is designed to efficiently fill the electron storage ring. The injection currently takes place at 540 MeV, two times per day. After the accumulation of electron current, the energy is ramped up inside the ring to 1.5 GeV via two active RF cavities.
Top-up injection would be of extreme benefits for user operation, therefore here we present a simulation study for the...
A program is under way at the Argonne Wakefield Accelerator (AWA) facility, in collaboration with Euclid Techlabs and Northern Illinois University (NIU) to develop a GV/m-scale photocathode gun, with the goal of producing bright electron bunches. The novel X-band (11.7 GHz) photo-gun (Xgun) is powered by high-power, short rf pulses (9 ns), which are generated by the AWA drive beam in a...
The matter-antimatter asymmetry may be explained through CP-violation by observing a permanent electric dipole moment (EDM) of subatomic particles. An advanced approach to measure the EDM of charged particles is to apply a unique method of "Frozen spin" on a polarized beam in a storage ring. To increase the experimental precision step by step and to study systematic effects, the EDM experiment...
Developments of new research areas and breakthroughs in science are often linked to the progress in new instrumentation. Here we briefly summarize the scientific opportunities and the proposed layout of an X-ray Compton source based on superconducting accelerator technology. The X-ray source is envisioned to provide scientists at Uppsala University and collaborating research groups with 100...
SIS18 will be used as booster for FAIR’s main synchrotron SIS100. In addition, it provides a wide variety of ions from Protons to Uranium for users directly at GSI and FAIR.
An upgrade program to enhance the overall performance for the booster operation has been carried out.
Part of the upgrade program for booster operation was a complete overhaul of the control system including data...
Optimising the slice energy spread in X-ray free electron lasers (XFELs) is key to their effective operation, and must be considered from the photoinjector at the very beginning of the machine. The standard approach, in which the measured beam size is entirely attributed to the product of the dispersion and the energy spread, has only a resolution on the order of several keV, meaning that a...
At Eindhoven University of Technology a lab-based tabletop Inverse Compton Scattering (ICS) source is being commissioned. This compact and affordable X-ray source will bridge the gap between conventional lab X-ray sources and synchrotrons.
A 100 kV DC photo electron gun is used in combination with a bunching cavity to produce electron bunches that are injected in a X-band accelerator. The...
Inverse Compton Scattering (ICS) sources are becoming more popular as the future of lab-based x-ray sources. Smart*Light is one such facility, under commissioning at Eindhoven University of Technology (TU/e). This compact X-ray source aims at bridging the gap between conventional lab X-ray sources and synchrotrons.
Electron bunches are produced by a 100 kV DC photo electron gun in...
Seeding of free-electron lasers (FELs) is based on a periodic modulation of the electron energy by an external radiation pulse converted to a density modulation in a dispersive section. In complex configurations such as cascaded high-gain harmonic generation (HGHG) or echo-enabled harmonic generation (EEHG), the density-modulated electron beam may need to be propagated through drift spaces or...
After more than 40 years of operation in different machines, the Antiproton Decelerator (AD) electron cooler (e-cooler) is expected to be replaced by a new one designed at CERN. This new design is primarily driven by the necessity to ensure the reliable operation of the CERN antimatter facility for the next decade and beyond. This will also be the occasion to overcome the known limitations of...
The SPS proton fixed target beams are spilled via a third integer resonant extraction, for which high momentum spread is beneficial. To increase the momentum spread prior to the slow extraction, the bunches are stretched at the unstable phase by inverting the sign of the RF voltage. The RF phase is then flipped back, and the voltage is turned off when the bunch distribution is rotated to the...
Shanghai HIgh repetitioN rate XFEL and Extreme light facility (SHINE) is an x-ray FEL facility based on an 8 GeV CW superconducting linac and 3 FEL undulator lines, with the capability that delivering wide spectral range coherent radiation to multi end stations.
In this paper, we present the detailed dynamics design strategy based on global optimization with start-to-end simulations from...
Southern Advanced Photon Source (SAPS) is a 3.5 GeV diffraction limited storage ring, being planned to be built near the site of the China Spallation Neutron Source (CSNS). Full energy Linac injector reserves the possibility of using the Linac for free electron laser application in a future upgrade. In this paper, the start-to-end simulation of the full energy Linac working on the ring...
FACET-II is a National User Facility at SLAC National Accelerator Laboratory with the goal to develop advanced acceleration and coherent radiation techniques using a 10 GeV electron beam of unprecedented beam intensity with >100 kA peak current and <10 µm spot size, a 10 TW experimental laser system, and a variety of solid, gas and plasma targets. A diverse experimental program will...
The 70MeV cyclotron at Laboratori Nazionali di Legnaro was installed and commissioned in 2017 and the accelerator was operational until March 2021. The shut down was foreseen in order to permit the completion of the SPES facility, while the resume of activities is expected on 2023. The status of the cyclotron and related high intensity beamlines will be presented as well as the last...
To advance in the characterization of photocathodes for high brightness sources, the measurement of the thermal emittance plays a key role. The TRAnsverse Momentun Measurement device developed at INFN LASA will allow equipping our photocathode laboratory with an advance device able gving in quasi on-line feedback during the photocathode growth process.
This paper reports on the status of the...
The synchrotron SIS100 at FAIR, currently under construction in Darmstadt, Germany, will deliver slow extracted proton and ion beams up to 100 Tm employing resonant extraction. Its compact super-ferric dipole and quadrupole magnets allow fast ramping of magnetic field up to 4 T/s and 57 (T/m)/s, respectively. Recently, field errors has been measured for the dipole magnets and the first batch...
A beam cooler device has been constructed by the Laboratories de physique corpusculaire (LPC) of Caen (France) in collaboration with Laboratori Nazionali di Legnaro (INFN) for the SPES project. The design phase started in 2018 and the construction was carried out in 2021. In 2022 the functionality test have been done at LPC and the beam commissioning started. The Beam Cooler is capable to...
A prototype electron lens for space charge compensation in the synchrotron SIS18 that could pave the way for pushing the space charge limit of hadron synchrotrons is currently under development at GSI. Accompanied by beam transport simulations, a 3D construction model is being worked out as well as the integration into the existing accelerator facility. The electron gun and collector...
The European Spallation Source (ESS) aims to build and commission a 2 MW proton linac ready for neutron production in 2025. Commissioning of the normal conducting section of the linac is underway and previous papers have reported the performance of the microwave-discharge ion source, Radio Frequency Quadrupole (RFQ) and first Drift Tube Linac (DTL) tank.
This paper describes the recent...
FLUTE (Ferninfrarot Linac- Und Test-Experiment) at KIT has a compact versatile linear accelerator. One of FLUTE's main goals is to serve as a platform for a variety of accelerator studies as well as for the generation of high intensity, ultra-short THz pulses for photon science experiments. The linear accelerator is envisioned as an injector for a Very Large Acceptance compact Storage Ring...
The free-electron laser user facility at DESY – FLASH – is operating two undulator beamlines simultaneously and delivers XUV and soft X-ray radiation for photon experiments. It is driven by a superconducting linear accelerator. In a shutdown from November 2021 to August 2022 FLASH underwent a comprehensive refurbishment and a substantial upgrade (FLASH2020+). In this paper we summarize the...
The H– linac pre-injector used at the ISIS spallation neutron and muon source is being upgraded to include a medium energy beam transport (MEBT) line after the radio frequency quadrupole (RFQ). The improved beam transport allows the use of a more modern and reliable RF-driven H– ion source. To test the new ion source and MEBT for long-term end-to-end reliability, an...
The laser manipulations of H- ion beam by single or double neutralization is a very promising technique and highly essential to utilized in accelerator processes such as stripping, pulse chopping, collimation, extraction, and beam diagnostics for the present and future high-intensity proton accelerators. At J-PARC, we are preparing for a POP (Proof-of-Principle) demonstration 400 MeV H-...
In the framework of the FLASH2020+ project, the FLASH1 beamline will be upgraded to deliver seeded FEL pulses for users. This upgrade will be achieved by combining high gain harmonic generation and echo-enabled harmonic generation with a wide-range wavelength-tunable seed laser, to efficiently cover the 60-4 nm wavelength range. The undulator chain will also be refurbished entirely using new...
The heavy ion synchrotron SIS100 is the flagship accelerator of the Facility for Antiproton and Ion Research (FAIR) currently under construction at GSI, Darmstadt. It will provide high intensity beams of particles ranging from protons to uranium ions at beam rigidities up to 100 Tm. Part of the machine protection system is an emergency beam dump that is partly inside the vacuum system and...
Heavy ions have been accelerated for the first time by SPIRAL2 in 2022. A fast method to tune the linac cavities has been used (< 1 hour by now, < 10’ in the future) to obtain a 7 MeV/A 18O6+ beam (50 microA CW). Then an automatic Q/M beam change procedure has been successfully used to directly produce a 18O7+ beam. The goal was to demonstrate the possibility to tune a beam even if its...
For the China Spallation Neutron Source (CSNS), during the injection process, there are some stripped electrons. Because of their low energy, small number of particles, and wide distribution, we had not used an electron catcher to collect the stripped electrons for CSNS-I. However, for CSNS-II, the number of stripped electrons becomes large and the energy increases. Then, an electron catcher...
The SPIRAL2 installation at GANIL, Caen France is al-ready in operation since 2019 and produce a large num-ber of new radioactive ion beams at high intensities. In 2027, the DESIR facility will receive beams from the upgraded SPIRAL1 facility of GANIL (stable beam and target fragmentation) and from the S3 Low Energy Branch (fusion-evaporation and deep-inelastic reactions). The construction of...
European XFEL is a x-ray free-electron laser (FEL) user facility covering a nominal photon energy range from 250eV to 25keV. At the soft x-ray undulator beamline SASE3 and the two hard x-ray undulator beamlines SASE1 and SASE2, identical permanent magnet phase shifters are installed. In standard operation of the hard x-ray undulator beamlines these phase shifters introduce only small delays...
The search for the Electric Dipole Moments (EDM) of charged particles in storage rings necessitates polarized beams with long Spin Coherence Time (SCT) of the circulating beam. The SCT is the time during which the RMS spread of the orientation of spins of all particles in the bunch reaches one radian. A long SCT is needed to observe the coherent effect of a polarization build-up induced by the...
The electron accelerator S-DALINAC at TU Darmstadt was successfully operated in single and double-turn energy-recovery mode. The latter was realized using a shared beam-transport where two beams are superimposed in the first recirculation beamline. Due to its current design, the S-DALINAC can be upgraded with reasonable effort to be operated in triple-turn energy-recovery mode with shared...
A crystal-based hybrid e+ source could be a good alternative to conventional sources based on the e- conversion into e+ in a thick target and is currently under consideration for the FCC-ee [1]. In a hybrid source an e- beam crosses a thin oriented crystal with emission of channeling radiation, featuring enhanced photon flux w.r.t. Bremsstrahlung [2]. It results in an increase in the number of...
CSNSII is an upgrade project of China Spallation Neutron Source (CSNS), which needs to increase the beam power from 100kW to 500kW. In order to find a suitable working point area in advance and evaluate the influence of space charge effect on CSNSII, the measurements of beam loss with different tunes on CSNS was carried out and beam loss simulation in transverse tune space on CSNSII has been...
An energy-recovery-linac (ERL)-based X-ray free-electron laser (FEL) is proposed considering its three main advantages: i) shortening the linac by recirculating the electron beam by high-gradient SRF cavities, ii) saving the klystron power and reducing the beam dump power through the energy recovery in the SRFs, iii) producing a high average photon brightness with high average beam current....
Fermilab pre accelerator (Preacc) and Linac send H- beam at 15Hz to the Booster which is a resonant circuit synchrotron. The beam is accelerated from 35 keV to 750 keV with RFQ in the Preacc, and then accelerated to 400 MeV in the Linac. There are 17 cavities in the Preacc and Linac, however a few of the cavity phases are adjusted for a daily tuning. The phase and amplitude have not been...
Cryo-cooled C-band (5.7 GHz) copper distributed-coupling cavities are a new approach to the structure-based accelerators for the future multi-TeV energy range linear collider. It provides numerous degrees of freedom to optimize the cavity geometry to achieve high gradient and high-power in the linear collider. In this study, we analyze the dipole modes of C-band 20-cells cavity and calculate...
Nanostructured electron sources exhibiting simultaneous spatio-temporal confinement to nanometer and femtosecond level along with a low emittance can be used for developing future ordered electron sources to generate unprecedented electron beam brightness and can revolutionize stroboscopic ultrafast electron scattering and steady-state electron microscopy applications. In addition, high...
Extraction of beam from the Fermilab Delivery Ring for the Mu2e Experiment is hindered by large radiative losses initiated within the electrostatic septum (ESS) components of the resonant extraction system (RES). Of particular concern are beam losses causing potential damages to the support components of the RES, diminished intensity for experimental statistics, and high radiation levels in...
Terahertz radiation plays an important role in cutting-edge scientific research. Terahertz radiation source based on relativistic electron beam can provide excellent terahertz radiation source. The performance of such radiation is closely related to the distribution of the electron beam. Therein, the laser modulation technology based on the undulator is widely used to manipulate the...
The development of compact accelerator facilities providing high-brightness beams is one of the most challenging tasks in the field of next-generation compact and cost affordable particle accelerators. Recent results obtained at SPARC_LAB show evidence of the FEL laser by a compact (3 cm) particle beam plasma accelerator. This work is carried out in the framework of the SPARC_LAB activities...
Slowly extracted beams from a synchrotron have temporal fluctuations, the so-called spill micro structure. The reason is related to power supply ripples that act on the quadrupole magnets, leading to unintended tune fluctuations during extraction. Related simulations regarding the dependency of spill quality on the power supply ripples are executed with varying excitation levels of the...
The Los Alamos Neutron Science Center (LANSCE) is a highly versatile H-/H+ 800-MeV linear accelerator that serves five distinct user facilities. Currently, H+ is accelerated through the drift tube linac down a stub line for the Isotope Production Facility at 100 MeV. The other four user facilities at LANSCE use the H- beam accelerated to 800 MeV. The H+ beam had historically been accelerated...
Plasma wakefield acceleration (PWFA) is a burgeoning field, attracting much attention as an option to extend acceleration gradients from the present 100 MeV/m level to the TeV/m level. The effort will be expended to resolve the question of the long-term behaviour of the disturbances left behind in the plasma and the time it takes to reach equilibrium after the wakefield interaction occurs. The...
Online models are becoming increasingly more important for the tuning of particle accelerators. Photo-injectors are especially notorious due to there sometimes finicky nature and the difficulties involved in developing models that are suitable for online use. Surrogate models using artificial neural networks are increasingly popular for this application due to their ability to model nonlinear...
A key aspect of the LHC Injectors Upgrade project is the connection of the PSB to the newly built Linac4 and the related installation of a new 160\,MeV charge-exchange injection system. The new injection system was commissioned in winter 2020/21 and is now used operationally to tailor the transverse characteristics for the various beam types at CERN, such as high-intensity fixed target beams,...
High-Brightness SASE (HB-SASE) is a proposed method for greatly improving the temporal coherence of SASE FEL pulses using magnetic delay chicanes along the undulator beamline. Isochronous chicanes, which include high-strength quadrupoles, promise to deliver the greatest improvement in temporal coherence but it is more convenient if the delay chicanes are composed only of dipoles. In this paper...
A new tool is under development aimed at complementing the hadronic physics of GEANT4.
The tool interfaces most of the standalone nuclear interaction models and the pre-equilibrium and evaporation models to Geant4.
The tool can generate primary hadronic interactions between particles, ions, and matter.
The tool has been designed to optimize the design of targets for the next generation of...
The Advanced Wakefield Experiment (AWAKE) at CERN relies on the seeded Self-Modulation (SM) of a long relativistic proton bunch in plasma, to accelerate an externally injected MeV witness electron bunch to GeV energies.
During AWAKE Run 1 (2016-2018) and Run 2a (2021-2022), two seeding methods were investigated experimentally: relativistic ionization front seeding and electron bunch seeding....
X-ray free electron lasers (XFEL) and other x-ray producing light sources are large, costly to maintain, and inaccessible due to minimal supply and high demand. In addition, concepts for future electron colliders benefit from cost reduction size is reduced through normal conducting RF cavities are operated at very high gradients. It is advantageous then to consider miniaturizing electron...
Corrugated structure modules are being proposed for installation after the end of the linac and before the undulator regions of SHINE facility, where it has been used for energy chirp control and as a fast kicker for two color operation of the FEL.When ultra-relativistic bunch of electrons passing through corrugated structure will generate strong wakefield, we find most of the wake power lost...
Mega electron volt (MeV) accelerators used for ultrafast electron diffraction (UED) have provided a unique insight into visualizing elusive ultrafast processes from photochemical reactions and lattice motion, to phase transitions occurring in quantum materials. In this work, we demonstrate recent measurements of strong THz streaking of ultrafast electron bunches generated from an rf...
The terawatt-scale free electron lasers (FELs) are of great interest for the possibility to allow X-ray single molecular imaging experiments and nonlinear x-ray science. At Pohang Accelerator Laboratory X-ray Free Electron Laser (PAL-XFEL), for the second hard undulator plan (HX2) the enhanced Self-Amplified Spontaneous Emission (E-SASE) scheme with an external laser pulse will be installed to...
We present the latest developments of the test facility for LANSCE Front-End Upgrade. The upgrade will significantly improve the operations and reliability of LANSCE, with upgrade options for future capability. This effort includes a highly diagnosed ion injector, low-energy beam characterizations, and RFQ analysis. Comparisons between beamline measurements and simulations are presented.
Worldwide there is a push for producing medical isotopes using particle accelerators rather than fission reactions. Here we report on the operation of a DC-photogun designed for producing Mo-99 in the Lighthouse facility and commissioned by the Institute for Radio Elements (IRE, Belgium).
The gun is based on the successful CBETA design by Cornell University. It is installed at the RI site in...
Electron acceleration in solid-state plasmas is of interest within the Laser Wakefield Acceleration (LWFA) research. Layered nanostructures such as graphene nanoribbons can be used as targets for intense UV lasers to generate and accelerate electron bunches. We present numerical Particle in Cell (PIC) simulations of a novel sub-femtosecond self-injection scheme which relies on edge-plasma...
In this work, we develop a concept of an accelerator arranged as follows: electrons are accelerated by an electromagnetic field in a waveguide immersed in a longitudinal uniform axial magnetic field and a transverse spatially periodical undulator magnetic field. There are several types of resonances in such a system. Namely, cyclotron, undulator, and combined resonances. Herewith, these...
The C70XP is a cyclotron operated for production of radionuclides in nuclear medicine, for research in physics, radio-chemistry and biology. It aims at providing high intensity beams to the various experiment for long or very short time runs. The beam transverse distribution, e,g. homogeneity and emittance, has a great impact on the experiments. The ion source and subsequently the injection...
Cavity-based X-ray free-electron laser (XFEL) is promising to produce fully coherent pulses with the bandwidth of a few meV and very stable intensity, while the currently existing self-amplified spontaneous emission (SASE) XFEL is capable of generating ultra-short pulses with chaotic spectra. In general, cavity-based XFEL can provide spectral brightness three orders of magnitude higher than...
The “standard” way of a high energy positron beam in proton accelerator-driven systems includes two stages. Firstly, the proton beam is directed on a target material. The protons produce neutral pions that after a short decay they decay to 2 gamma rays. At the second stage, these gammas are producing electron-positron pairs on a high-Z (typically Pb) converter. Magnets between the target and...
Accelerator facilities are among the most complex projects, integrating advanced engineering systems and components. At the ESS, the need to visualise the intricate integration activities has led to the development of Aggregation Diagrams (ADs). The diagrams follow the facility breakdown structure with sections and system diagrams showing their integration of the devices with enabling and...
Particle accelerators demand high particle transmission and reduced longitudinal emittance; hence, effective bunching systems are requested. The concept based on an efficient, compact design called “Double Drift Harmonic Buncher - DDHB” fulfills these two requirements for a c.w. or pulsed beam injection into an RFQ, a DTL, or a cyclotron. The proposal is associated with two buncher cavities...
The Extreme Photonics application Centre (EPAC) is a planned UK national facility. The current intention is for EPAC to use a 1 PW 10Hz laser system to drive laser plasma acceleration with output energies ranging from 100 MeV up to, at least, 5 GeV. The initial design for the electron beam transport of the EPAC facility is presented in this paper. This includes some initial considerations on...
The EIC requires an electron gun to provide a high current high brightness electron beam for EIC cooler. A 550 kV DC gun using alkali antimonide photocathode was designed to generate a 110 mA electron beam , 1 nC with normalized emittance < 1 mm-mrad. Here, we present the design parameters of this high voltage DC gun. The details of the gun design with electron beam simulation will be described.
As part of the goal of increasing the beam power of the Main Ring for Fast eXtraction (FX) in J-PARC to 750 kW, the two low-field septa and three high-field septa for FX were installed into MR in 2022. The most significant goals regarding the magnets are achieving an extremely low leakage field in the circulating line. To reduce the leakage field in
the circulating line, the new pure iron...
A new proton beam-delivery line for the TOP-IMPLART linac is under assembly and testing at the ENEA Frascati Research Center. TOP-IMPLART is an RF pulsed linear accelerator developed for medical applications, consisting of a 425 MHz, 7 MeV injector, followed by eight accelerating SCDTL modules operating at 3 GHz, driven by two 10 MW peak power klystrons. Proton beam can be accelerated at 63...
Subcritical Assembly Neutron Source facility of the National Science Center “Kharkiv Institute of Physics & Technology” (NSC KIPT), Kharkov, Ukraine is Accelerator Driven System with tungsten or uranium neutron generating target and 100MeV/100kW electron linear accelerator as a driver.
The facility physical start up was started in the middle of 2020 fnd completed in August 2022. The program...
SNRC and CEA collaborate to the upgrade of the SARAF accelerator to 5 mA CW 40 MeV deuteron and proton beams (Phase 2). CEA is in charge of the design, construction and commissioning of the linac downstream the existing RFQ (SARAF-LINAC Project).
The MEBT is now installed at SNRC and has been commissionined with beam. Transverse and longitudinal emittances have been measured and beam...
The minimum achievable particle beam emittance in an electron accelerator depends strongly on the intrinsic emittance of the photocathode electron source. Reducing the electron beam emittance in an accelerator which drives a FEL delivers a significant reduction in the saturation length for an X-ray FEL, thus reducing the machine’s construction footprint and operating costs whilst increasing...
Electron field emission and the related process of strong laser-field emission are promising mechanisms for the creation of high brightness beams. These processes deviate from the photoelectric effect in that the normal energy – not the total energy – is the predominant factor determining the likelihood for an electron to ionize. In this paper we continue our investigation of the material...
This article presents an IH-DTL prototype, capable of accelerating carbon ion beams from 5 MeV/u to 5.5 MeV/u, for manufacturing and assembling validation in a hadrontherapy linac injector. A multi-physics study is made in CST Studio concerning steady-state thermal, stress and deformation analysis. Convenient water-cooling circuits close to drift tubes are simulated to evaluate field errors...
In this paper, a cooling scheme was designed for the THU VHF gun, and simulations of thermal and structural analyses were conducted. A total of 19 independent cooling channels were designed and distributed on the gun to remove the heat generated. The maximum temperature was 67.8 ℃ with a total flow rate of 3.28 L/s and dissipation power of 92.5 kW. The accelerating gap distance decreased by...
Strong laser-field electron emission enhanced by nanostructures is a growing topic of study, owing to its ability to generate high brightness beams. Experiments have shown that the nanoblade structure, a wedge shape, notably outperforms nanotips in the peak fields achieved. These higher fields result in a brighter emission. In this paper we study the thermodynamics of the electron system...
We study THz radiation generation from a few-periods magnetic device for THz pump – x-ray probe experiments at the European XFEL, or at other facilities like the LCLS-II. We compute THz radiation accounting for the boundary conditions imposed by a vacuum pipe. Calculations were performed for a single-period magnetic device as well as for a nine-period one. We address the problem of modes...
The LHC Injector Upgrade (LIU) programme forms a cornerstone of the High-Luminosity LHC project. Among its targets, a new Beam Position Monitor (BPM) system has been deployed in the Low Energy Ion Ring (LEIR) to facilitate optics measurements. This paper reports on the commissioning and analysis of turn-by-turn data from the new BPM system. Furthermore, the specific challenges and current...
Semiconductor photocathodes, particularly those produced with thin films and heterostructures, are promising candidates of high brightness electron sources. It is also well-known that electron beam brightness increases with the photocathode gun’s operating gradient. Combining both heterostructure semiconductor photocathode and cyro-cooled high-gradient photocathode gun may improve electron...
The ALTO research platform at the Laboratoire de physique des 2 infinis Irène Joliot Curie (IJCLab) is dedicated to wide-ranging research in nuclear physics, nuclear astrophysics and interdisciplinary activities such as health physics. ALTO-LEB is the low energy beam area of ALTO where neutrons rich exotic nuclei are studied.
A new precision experiment is being installed at the ALTOLEB...
A 1 MeV/n Radio-Frequency Quadrupole (RFQ) has been developed and commissioned at Korea Multipurpose Accelerator Complex (KOMAC). The RFQ is designed to accelerate ions with mass to charge ratio up to 2.5. The designed peak current is 10 mA with 10 % duty factor. Currently we are utilizing the RFQ as a test bench for the reliable operation of the 100 MeV proton linac operational at KOMAC since...
The design betatron tune of the rapid cycling syn-chrotron (RCS) of China Spallation Neutron Source (CSNS) is (4.86, 4.78), which enables incoherent tune shifts to avoid serious systematic betatron resonances. Serious beam instability was observed when the opera-tional bare tune was set to (4.86, 4.78). The tunes dur-ing the beam acceleration were optimized based on the space charge tune shift...
Particle accelerators are devices of primary importance in a large range of applications such as fundamental particle physics, nuclear physics, light sources, imaging, neutron sources, and transmutation of nuclear waste. They are also used every day for cargo inspection, medical diagnostics, and radiotherapy worldwide. Electron is the easiest particle to produce and manipulate, resulting in...
In this proceeding, we demonstrate the synthesis of epitaxial Cs$_3$Sb films with a high degree of crystallinity on silicon carbide substrates. Films less than 10 nm thin are grown in vacuum and exhibit percent level quantum efficiencies at 532 nm. We find a positive correlation between quantum efficiency and improved crystallinity of the photocathode film, particularly in the longer...
We are developing an ultrafast and ultracold electron source (UCES), based on near-threshold femtosecond photoionization of a laser-cooled cloud of rubidium gas, stored in a Magneto Optical Trap (MOT). The UCES is characterized by electron temperatures as low as ~ 10 K, enabling a unique combination of ultra-low emittance ~ 1 nm rad and relatively high bunch charges. Recently we have...
High brightness photoinjectors demand low thermal emittance and high electric field to deliver brighter electron beams for modern accelerator-based scientific instruments. High quantum efficiency, low thermal emittance photocathodes, mainly semiconductors, easily degrade in poor vacuum conditions and could not operate with an extended lifetime. Therefore, an ultrahigh vacuum electron gun is...
This talk will report on the status C-band high gradient research program at Los Alamos National Laboratory (LANL). The program is being built around two test facilities: C-band Engineering Research Facility in New Mexico (CERF-NM), and Cathodes And Radio-frequency Interactions in Extremes (CARIE). Modern applications require accelerators with optimized cost of construction and operation,...
LNL heavy ion accelerator complex is based on three main accelerators: Tandem, ALPI and PIAVE. The Tandem XTU is a Van de Graaff accelerator normally operated at terminal voltages of up to about 14 MV. It can be operated in stand–alone mode or as an injector for the linac booster ALPI. The linear accelerator ALPI is built of superconducting resonant cavities and consists of a low–beta branch,...
A 350 MHz, 3 MeV radio frequency quadrupole (RFQ) has been operating since 2005 at Korea Multi-purpose Accelerator Complex (KOMAC) as a low energy part of the 100 MeV proton linac. Recently, it was considered to upgrade the existing RFQ because of its low beam transmission rate and vane erosion. Several options were compared to upgrade the RFQ considering a number of sections, coupling plate...
The Large Hadron electron Collider (LHeC) is proposed as a future particle physics project colliding 60 GeV electrons from a six-pass recirculating energy-recovery linac (ERL) with 7 TeV protons stored in the LHC. The ERL technology allows for much higher beam current and, therefore, higher luminosity than a traditional Linac. The high-current, high-energy electron beam can also be used to...
Tetrode vacuum tubes are used under the positive grid region
to accelerate a high intensity beam in the RCS.
A tube amplifier is operated in push-pull mode and two tubes are installed in the amplifier. Although each control grid should be driven in counterphase for the push-pull operation, the waveform becomes asymmetric by the positive grid biasing. The vacuum tube operation analysis...
For HL-LHC intensities, transient beam loading after injection between the Super Proton Synchrotron (SPS) and the Large Hadron Collider (LHC) is expected to push the RF power in the LHC to the limit of the installed system. A detailed understanding of this process is necessary to minimize beam losses during LHC injection. Realistic models of the local SPS and LHC cavity control systems were...
Experiments at CRYRING using beams accelerated and decelerated in the accelerator chain SIS18 - ESR - CRYRING at GSI are considered as the first real FAIR experiments. For these experiments, CRYRING receives fast extracted beams from the ESR, which are cooled and decelerated down to about 10 MeV/u in the ESR. The beam transport from ESR to CRYRING is difficult, since part of the beamline has...
Wakefield acceleration in structured solids (nanotubes and crystals) has a promise of very high accelerating gradients and simultaneous continuous channeling focusing. All that can manifest a new, long thought solution of many challenges faced by advanced acceleration techniques. We outline the concept and present the progress and status of the E336 Experiment at FACET-II.
The Shanghai high-repetition-rate XFEL and extreme light facility (SHINE) is designed to be one of the most advanced free electron laser user facilities around the word. The repetition is aiming at 1 MHz and the high-repetition-rate electron beams are delivered into three undulator lines through the beam delivery section. The main functional elements are kickers. The vacuum chamber in the...
The energy loss of the electron beam due to synchrotron radiation and wakefields determines an undulator tapering in order to keep the resonance condition along the undulator. The contribution of synchrotron radiation to energy loss can be calculated analytically, whereas the calculation of wakefield energy loss requires knowledge of the beam current profile and the wakefield function at the...
FEL oscillator is the main working mode to produce infrared and THz radiation. However, in the long wavelength range, the waveguide is essential to suppress the diffraction losses. We have developed a method to study this effect by wGenesis that is modified with Genesis in combination with OPC code. However, this method is limited by the optical elements given in OPC. In this paper, we tried...
We have been developing an in-situ work function (WF) measurement system to investigate an unexpectedly short lifetime problem of a CeB6 thermionic cathode at the SACLA electron injector. Photoelectron yield spectroscopy using a nanosecond tunable pulsed laser in the wavelength range from 410 to 709 nm was adopted because this method provides a high S/N ratio in a hot operational condition of...
In our recent work [1], we proposed a plasma-driven light source that can generate coherent tunable XUV pulses with TW peak power and pulse durations of 40 attoseconds (or longer) in a m-length undulator. The pulses synthesized in this approach carry particular merit for tracking chemical dynamics and enabling measurements that extend beyond the range of conventional HHG and XFEL...
