bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design of a 250 MeV linac injector system for the Southern Advanced Photon Source
Authors: Han Yanliang , Huang Liangsheng , Liu Xingguang , Jiao Yi , Wang Sheng 
Published: January 2024

Abstract
The Southern Advanced Photon Source (SAPS) is a 4th generation storage ring based light source under design started several years ago, which is planned to be constructed at Guangdong province at China. The equilibrium emittance of the storage ring(SR) will be below 100 pm.rad and the beam energy is determined to be 3.5 GeV. Over the past two years, the nominal current of the SR was increased from 200 to 500 mA, requiring the injector system to provide more bunch charge. Additionally, the injection beam energy for the booster has been increased from 150 to 250 MeV, which means two more accelerating cavities have to been added. This paper presents an update of the linac injector. And also a beam transfer line from linac to booster is presented.
A novel scheme based on angular dispersion-induced microbunching mechanism for harmonic generation in storage ring
Authors: Lu Yujie , Feng Chao , Wang Dong 
Published: January 2024

Abstract
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 order simulation demonstrate that it is possible to produce ultrahigh harmonic coherent radiation in the storage ring. The high harmonic conversion efficiency of the proposed scheme may open up a new opportunity to produce sub-nanometer X-ray coherent radiation in the storage ring.
Feasibility verification of ultrafast FEL generation experimental scheme based on SXFEL
Authors: Xiao Yaozong , Feng Chao , Sun Hao , Liu Bo 
Published: January 2024

Abstract
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. In this paper, the feasibility of ESASE experiments on Shanghai Soft X-ray Free Electron Laser Facility (SXFEL) is theoretically verified. The results show that the ESASE scheme can produce ultrafast light pulses on the order of attosecond, with a peak power of 450 MW. At the same time, the simulation results in this paper verify the feasibility of chirped enhanced SASE schenme based on SXFEL. The results show that compared with the ESASE scheme, the power of the radiation pulse can be greatly improved by this scheme. A relatively low energy electron beam (1.5 GeV) was used to generate about 40 GW of radiation, and the length of the radiation pulse was significantly shortened.
Enhanced harmonic generation for high-repetition-rate soft x-ray free-electron laser
Authors: Yang H , Yan J , Deng H 
Published: January 2024

Abstract
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, the seed laser at the ultraviolet region cannot induce sufficient energy modulation at high repetition rates due to state-of-the-art laser system limitations. A recently suggested self-modulation scheme shows that the peak power requirement of a seed laser can be reduced by around one order of magnitude in an HGHG setup. In this paper, we present start-to-end simulation results to estimate the feasibility of the self-modulation-enhanced HB-HGHG scheme.
Performance of laser patterned copper plasmonic photocathodes
Authors: Martinez-Calderon M , Groussin B , Bjelland V , Chevallay E , Himmerlich M , Lorenz P , Marsh B , Neupert H , Rossel R , Wuensch W , Granados E 
Published: January 2024

Abstract
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 improving metallic photocathodes photoemission behavior enabling their use for next generation high brightness electron sources. Our goal is to investigate such surface-plasmon assisted photoemission processes with a view on simplifying the photocathode production at CERN while extending the lifetime of existing photoinjectors. The performance of two different femtosecond laser nanopatterned plasmonic photocathodes was analyzed by measuring the quantum yield with a 65kV DC electron gun utilizing 266nm laser excitation generated by a nanosecond laser with 5ns pulse duration and 10Hz repetition rate. By comparing the electron emission of the copper surface nanostructured areas with that of a flat area, our results suggest quantum yield enhancements of up to a factor of 5.
High-power experiment of a C-band photocathode gun
Authors: Wang Cheng , Tan Jianhao , Huang Xiaoxia , Xiao Chengcheng , Gao Zihe , Fang Wencheng 
Published: January 2024

Abstract
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 high-power test, and has preliminary reached the designed gradient on the cathode, 150MV/m with a repetition rate of 10Hz and pulse length of 2.5μs. The gun shows the potential for better performance with a higher gradient during high-power operation. Under extreme conditions, the gradient on the cathode is about 180MV/m. These high-power experimental results are the basis of the beam dynamics iteration and beam testing.
Status update on SUNDAE2 magnetic field test facility at European XFEL
Authors: Baader J E , Abeghyan S , Alanakyan L , Casalbuoni S , La Civita D , Englisch U , Marchetti B , Yakopov G , Yakopov M , Ziolkowski P , Eckoldt H J , Hauberg A , Lederer S , Lilje L , Wohlenberg T , Zimmermann R , Grau A W 
Published: January 2024

Abstract
The implementation and further improvements of superconducting undulators are part of the European XFEL facility development program. Within this program, a magnetic field test facility is being developed. Named SUNDAE2 (Superconducting UNDulAtor Experiment 2), it aims to perform in-vacuum magnetic field measurements of superconducting undulators (SCUs) with three techniques: Hall probe, moving wire, and pulsed wire. This contribution presents the updates and status of SUNDAE2.
A C-band Test Platform for the Development of RF Photo Cathode and High Gradient Accelerating Structures
Authors: Liu X , Li X , Jiang S , Liu S , Xiao Y , Lv Y , Cao X , Lu Z , Liu R , Zhang H , Xie Z , Huang W , Yang R , Yang T , Deng C , Ning C , Yu Y , Wei J , Wang P , Wang Y , Zhao G , Wang L , Xue K , Wu Q 
Published: January 2024

Abstract
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. A 3.6-cell C-band RF photo cathode has been manufactured and now is under test. In addition, studies such as the design for a C-band RF traveling-wave accelerating structure and the design of a C-band high gradient parallel-coupled accelerating structure utilizing short pulse are introduced.
Design of an E × B chopper based on permanent magnets
Authors: Jia Duanyang , Wang Zhijun , Xu Zhenyu , Chen Weilong , Chu Yimeng , Su Chunguang 
Published: January 2024

Abstract
Chopper systems are typically used to provide beam time structure and ensure the safety of accelerator operation by deflecting the beam away. The reliability of conventional choppers is entirely based on high-voltage (HV) pulsed power supplies. However, when the power supply fails to charge the electrostatic deflection plate, the beam cannot be cut off, and it will enter the downstream accelerator. To meet the strict beam stopping time requirements of the China Initiative Accelerator Driven System (CiADS), novel E × B chopper design has been developed based on a permanent magnet and an electrostatic deflection plate. This design not only ensures the safety of the accelerator but also provides the necessary pulse waveform. The device is small, highly reliable, and suitable for most accelerators. Moreover, beam dynamics simulations have been conducted to evaluate the chopper’s influence on beam quality, and its beam cutting capability has been analyzed.
Closed-orbit Distortion study of XiPAF upgrading project synchrotron
Authors: Xiong Yang , Yao Hongjuan , Liu Xiaoyu , Wang Zejiang , Li Yan , Zheng Shuxin , Wang Xuewu 
Published: January 2024

Abstract
Xi’an 200 MeV proton application facility (XiPAF) upgrading project is now in the design phase. A six super periods synchrotron is the main component of this project. Using MADX program, a statical analysis of the relationship between closed-orbit distortion (COD) and different types of magnet errors was carried out. Because we do not know the exact error in the design phase, we use rms value to represent errors and CODs. The results show that COD is in direct proportion to magnet error in some cases while the others are square proportional. We regard all the cases as direct proportional since the errors are usually small and find that the error amplification factors differ a lot. These results can give us some meaningful guide in lattice design and magnet error control.
Advanced basic layout of the HElmholtz LInear Accelerator for cw heavy ion beams at GSI
Authors: Barth W , Basten M , Burandt C. , Conrad T. , Dziuba F , Gettmann V , Kürzeder T , Lauber S. , List J. , Miski-Oglu M , Podlech H. , Scheeler U. , Schwarz M , Yaramyshev S 
Published: January 2024

Abstract
The design and construction of continuous wave (cw) high intensity linacs is a crucial goal of worldwide accelerator technology development. The standalone sc heavy ion linac HELIAC (HElmholtz LInear ACcelerator) 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 2017 the first section of the linac has been successfully commissioned and extensively tested with beam at GSI, featuring the capability of 216.816 MHz multi-gap Crossbar H-mode (CH) DTL-structures. At present, the first fully equipped cryomodule of the HELIAC is under construction. In addition, six further superconducting CH cavities are being procured. The HELIAC beam dynamics concept foresees a total of twelve CH-cavities in order to accelerate ions with a mass-to-charge ratio of 6 up to an energy of 7.5 MeV/u. In this paper, an advanced very compact and less complex layout is presented, where the same number of accelerating cavities can be accommodated in three instead of four cryomodules, thus also reducing the number of solenoids and rebunchers. In addition, the integration and linking of the HELIAC to the GSI accelerator UNILAC will be outlined.
RF-Acceleration Studies for the HBS-Linac Applying Alternating Phase Focusing Concepts
Authors: Lauber S. , Barth W. , Basten M. , Burandt C. , Droba M. , Dziuba F. , Forck P. , Gettmann V. , Gutberlet T. , Kürzeder T. , List J. , Miski-Oglu M. , Podlech H. , Schwarz M. , Yaramyshev S. 
Published: January 2024

Abstract
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 generate further the idea of drift tube linacs with alternating phase focusing (APF) beam dynamics, originally proposed in the 1950s. This focusing method uses the electric fields in between the drift tubes (i.e., gaps) to provide subsequent transverse and longitudinal focusing to the beam along multiple gaps. The beam focusing properties within each gap are adjusted individually by means of the synchronous phase. As a result of the alternating phase focusing method, these linacs can operate completely without internal magnetic lenses. The R&D-program for the high brilliance neutron source HBS offered the opportunity to investigate the APF concept further in order to open this advanced concept for high duty-factor, high intensity hadron beam acceleration. Besides, a prototype APF-interdigital H-mode (IH)-cavity has been designed and is going to be build and tested in the next future.
Pre-experiment of 70 MeV H
- cyclotron for producing ISOL RI beam.
Authors: Yeon Y. H. , Heo S. J. , Kim J. W. , Park D. J. , Hwang W. J. , Yim H. J. , Jeong J. W. , Hashimoto T. , Yoo K. H. , Lee J. H. 
Published: January 2024

Abstract
The Rare Isotope Science Project (RISP) is currently constructing equipment and facilities for the Rare Isotope Accelerator complex for ON-line experiments (RAON). The first experiment being conducted involves the acceleration of a proton to 70MeV using a cyclotron, which is then delivered to a SiC target to generate a radioactive isotope beam in the ISOL system. However, before conducting this experiment, a preliminary experiment was performed to confirm the exact location and shape of the proton beam to prevent loss of the proton beam. The pre-experiment involved configuring a faraday cup, wire grid scanner, collimator, and slit inside the proton beam diagnostic module to understand the characteristics of the proton beam at the target position. The beam current ranged from 1 μA to 1.5 μA, and the beam size was confirmed to be within the 2×2cm
2 slit size.
Estimation of the Anode Power Supply Current of the J-PARC MR RF system for 1.36s cycle operation
Authors: Sugiyama Yasuyuki , Tamura Fumihiko , Yoshii Masahito , Ohmori Chihiro , Yamamoto Masanobu , Hara Keigo , Hasegawa Katsushi , Nomura Masahiro , Shimada Taihei , Okita Hidefumi , Miyakoshi Ryosuke 
Published: January 2024

Abstract
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 the RF cavity. Beam acceleration in a shorter MR cycle requires a higher RF voltage to keep the RF bucket large enough and a larger anode power supply current for the beam loading compensation. We plan to add RF systems to achieve higher RF voltage and to manage the output current of each anode power supply under limitations. To estimate the anode power supply current with a shorter MR cycle, we derived the beam loading compensation contribution in the power supply current using the data recorded during the operation with a cycle time of 2.48 seconds. We present the estimated anode power supply current for various combinations of RF voltage and the number of RF cavities.
A scheme to extract the beam in advance and transverse beam distribution measurement for the CSNS RCS
Authors: Huang Ming-Yang , Zhu Peng , Xu Shouyan , Li Mingtao , Yuan Yue , Wang Sheng 
Published: January 2024

Abstract
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 1.6 GeV, and the extraction repetition frequency is 25 Hz. In order to optimize the painting distribution and reduce the beam loss in the beam commissioning, it is necessary to measure the transverse beam distribution during the injection and acceleration processes. In this paper, a scheme to extract the beam in advance is proposed which is performed by adjusting the extraction timing and extraction mode. By using this extraction mode, the beam can be extracted at different time and the transverse beam distribution can be measured by a multi-wire scanner located on the beam transport line from the RCS to the target. Then, the beam distribution at the desired position on the RCS can be deduced by using the beam transfer matrix.
Multiturn Injection Design and Optimization for XiPAF-Upgrading Synchrotron
Authors: Liu X. Y. , Yao H. J. , Li Y. , Wang Z. J. , Xiong Y. , Zheng S. X. , Wang X. W. 
Published: January 2024

Abstract
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-Upgrading synchrotron multiturn injection scheme, simulation results by PyORBIT[1] show that the injection efficiency is ∼85% for proton and ∼80% for heavy ions. The influence of space charge and magnet errors on accumulated particle number has been studied by simulation.
Study on XiPAF-Upgrading Synchrotron Beam Loss
Authors: Liu X. Y. , Yao H. J. , Yuan Y. S. , Li Y. , Wang Z. J. , Xiong Y. , Zheng S. X. , Wang X. W. 
Published: January 2024

Abstract
Xi’an 200MeV proton application Facility (XiPAF) is upgrading its proton synchrotron to a multi-ion synchrotron, which replaces H- stripping injection with multiturn injection scheme. New synchrotron’s vertical tune has been changed from 1.70 to 2.26, beam dynamics of new lattice is much different from the original proton lattice. Simulations has been performed with PyORBIT for beam loss study, with or without space charge effect. The main beam loss is caused by 3-order incoherent resonance νx
+ 2νy
= 6, which is a structure resonance. Space charge and longitudinal synchrotron motion speed up the beam loss process.
The impact of the resistive-wall impedance on the ILSF storage ring
Authors: Khosravi N , Dastan S , Akhyani M , Ahmadi E 
Published: January 2024

Abstract
The resistive contribution of the vacuum chamber represents a significant source of the collective effects and should be analysed in several aspects. Due to the NEG-coated re-designed ILSF vacuum chamber, the resistive-wall effects were carefully studied. The measurement setup of the RW test was simulated and compared with the analytical equations. Finally, the longitudinal threshold was presented here to estimate the RW effects on the single bunch instability.
Beam Coupling Impedance Contribution of Flange Aperture Gaps: a Numerical Study for Elettra 2.0
Authors: Cleva S. , Cudin I. , Karantzoulis E. , Rumiz L. , Comisso M. , Passarelli A. 
Published: January 2024

Abstract
The accurate analysis of any possible source of beam instability is mandatory for the design of a new particle accelerator, especially for high-current and ultra-low emittance synchrotrons. In the specific case of instabilities driven by the coupling between the charged particle beam and the electromagnetic field excited by the beam itself, the corresponding effect is estimated through the beam coupling impedance. The modeling of this effect is essential to perform a rigorous evaluation of the coupling impedance budget able to account for all devices present in the entire machine. To deal with this problem, this paper focuses on the estimation of the contribution of the joints lying between the different vacuum chamber sections, by performing a comparative numerical analysis that takes into account different aperture gaps between the flanges. The results point out the criticality of many small-impedance contributions that, added together, must be lower than a predefined impedance threshold.
CSR-induced Projected Emittance Growth Study For The Beam Switchyard At The European XFEL
Authors: Long T. , Chen Y. , Decking W. , Geloni G. , Golubeva N. , Huang S. , Liu S. , Qin W. , Scholz M. 
Published: January 2024

Abstract
Minimizing projected emittance of high brightness electron beam is important for efficient overlap between electron beam and radiation pulse in an FEL facility. Coherent synchrotron radiation (CSR) emission in a single bending section in the beam transport system usually introduces different slice energy modulation hence different slice transverse kicks in the designed dispersion-free lattice, causing projected emittance growth. Here we present theoretical and simulation study of CSR effect on the projected emittance growth in the beam switchyard arc before SASE2 undulator beamline at the European XFEL. We analyze arc optics impact on CSR effect and discuss possible schemes for emittance degradation compensation.
Accelerating Dynamic Aperture Evaluation Using Deep Neural Networks
Authors: Croce D. Di , Giovannozzi M. , Pieloni T. , Seidel M. , Van der Veken F. F. 
Published: January 2024

Abstract
The Dynamic Aperture is an important concept for the study of non-linear beam dynamics in a circular accelerator. The DA is defined as the extent of the phase-space region in which the particle’s motion remains bounded over a finite number of turns. Such a region is shaped by the imperfections in the magnetic fields, beam-beam effects, electron lens, electron clouds, and other non-linear effects. The study of the DA provides insight into the mechanisms driving the time evolution of beam losses, which is essential for the operation of existing circular accelerators, such as the CERN Large Hadron Collider, as well as for the design of future ones. The standard approach to numerical evaluation of the DA relies on the ability to accurately track initial conditions, distributed in phase space, on a realistic time scale, and this is computationally demanding. To accelerate the angular DA calculation, we propose the use of a Machine Learning technique for the angular DA regression based on simulated HL-LHC data. We demonstrate the implementation of a Deep Neural Network model by measuring the time and assessing the performance of the angular DA regressor, as well as carrying out studies with various hardware architectures including CPU, GPU, and TPU.
Initial Application of Machine Learning for Beam Parameter Optimization at the Hefei Light Source II
Authors: Yu Yongbo , Ni Wangbiao , Liu Gongfa , Xu Wei , Li Chuan , Li Weiming , Xuan Ke 
Published: January 2024

Abstract
Machine learning (ML) has become a valuable tool in particle accelerator control, with growing potential for beam parameter correction. In this study, we present preliminary ML applications at HLS-II, using Lasso regression for online tune correction and a neural network (NN) for beta function simulation correction. Both models were trained with supervised learning on measured beam parameter data, while an improved genetic algorithm optimized the NN structure. Our results show that the ML-based approach achieves competitive correction quality with fewer steps, making it a promising method for future particle accelerator applications and other fields.