Physical Review Accelerators and Beams最新文献

{"title":"Beam gas curtain monitor: Vacuum studies for LHC integration and operation","authors":"C. Castro Sequeiro, M. Ady, G. Bregliozzi, N. Chatzigeorgiou, A. R. Churchman, R. Kersevan, T. Lefevre, S. Mazzoni, G. Pigny, A. Rossi, M. Sameed, G. Schneider, O. Sedlacek, K. Sidorowski, C. Vazquez Pelaez, R. Veness, L. Zygaropoulos, O. Stringer, A. Webber-Date, C. P. Welsch, H. Zhang, P. Forck, S. Udrea","doi":"10.1103/physrevaccelbeams.27.043201","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.043201","url":null,"abstract":"A beam gas curtain (BGC) monitor has been designed to obtain information about the relative position between the LHC proton beam and the hollow electron lens electron beam through a minimally invasive process. Its working principle relies on intersecting the path of both beams with a supersonic gas curtain, introduced transversely into the LHC beamline, to produce a fluorescence signal. As an intermediate project stage (phase II), a preliminary version of the BGC monitor has been installed into the LHC beamline. To ensure the successful integration of the monitor and subsequent operation under LHC ultrahigh vacuum conditions, a series of vacuum studies have been performed. These can be classified as follows: An off-line laboratory test campaign, to assess BGC behavior during pump down and gas injections; simulations and analytical calculations, to evaluate BGC behavior and estimate the impact of its installation and operation in the LHC. This document will briefly present the off-line tests campaign, followed by a more extensive description of the simulations performed.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140598947","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Terahertz-driven acceleration of subrelativistic electron beams using tapered rectangular dielectric-lined waveguides","authors":"Laurence J. R. Nix, Joseph T. Bradbury, Christopher T. Shaw, Morgan T. Hibberd, Darren M. Graham, Robert B. Appleby, Graeme Burt, Rosa Letizia, Steven P. Jamison","doi":"10.1103/physrevaccelbeams.27.041302","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.041302","url":null,"abstract":"We investigate the use of tapered rectangular dielectric-lined waveguides (DLWs) for the acceleration of low-energy, subrelativistic, electron bunches by the interaction with multicycle narrowband terahertz (THz) pulses. A key challenge exists in this subrelativistic regime; the electron velocity changes significantly as energy is gained. To keep electrons in the accelerating phase, the phase velocity must also be increased to match. We present simulations which demonstrate that the dielectric thickness can be kept constant and the width of the dielectric lining can be tapered along the direction of travel to vary the phase velocity, an approach only possible by the use of a rectangular waveguide geometry. The properties of tapered DLWs are discussed and following this, a design process is presented to demonstrate that the way this tapering can be optimized for different pulse and beam parameters. The minimum accelerating gradient for electron bunch capture is derived and compared to simulations. As examples of this design process, designs are considered based on considerations of the THz source, incoming electron beam, and manufacturing tolerances. A maximum THz pulse energy of <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mn>22.5</mn><mtext> </mtext><mtext> </mtext><mi mathvariant=\"normal\">μ</mi><mi mathvariant=\"normal\">J</mi></mrow></math> in the DLW was considered, which represents what is readily achievable using mJ-level regenerative amplifier laser systems together with optical-to-terahertz conversion in lithium niobate crystals. This will be more than double the energy of a 100 keV electron beam, increasing it to 205 keV. We describe the optimization process and present a detailed exploration of the beam dynamics, discussing how the performance will further improve with compressed bunches.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140598914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Breakdown insensitive acceleration regime in a metamaterial accelerating structure","authors":"Dillon Merenich, Brendan Leung, Gaurab Rijal, Xueying Lu, Scott Doran, Gongxiaohui Chen, Wanming Liu, Chunguang Jing, John Power, Charles Whiteford, Eric Wisniewski","doi":"10.1103/physrevaccelbeams.27.041301","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.041301","url":null,"abstract":"A new regime in radiofrequency (rf) breakdown, named the breakdown insensitive acceleration regime (BIAR), was observed in an 11.7 GHz metamaterial structure for wakefield acceleration driven by rf pulses with a duration of a few nanoseconds. In the BIAR, rf breakdown occurs without interrupting potential beam acceleration, resulting in greater resilience to breakdown. We have investigated the possibility that BIAR can support higher gradients by characterizing the breakdown in a high-power test. The peak gradient reached <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mn>190</mn><mtext> </mtext><mtext> </mtext><mi>MV</mi><mo>/</mo><mi mathvariant=\"normal\">m</mi></mrow></math> when the structure was powered by 6 ns long rf pulses with 115 MW peak power. The short rf pulses were extracted from 65 MeV electron bunch trains with a total charge of up to 210 nC. This work has revealed the benefits of short-pulse acceleration by characterizing rf breakdown in the previously unexplored parameter space.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140599387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Longitudinal compression of a macrorelativistic electron beam","authors":"An Li, Jiaru Shi, Hao Zha, Qiang Gao, Liuyuan Zhou, Huaibi Chen","doi":"10.1103/physrevaccelbeams.27.044402","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.044402","url":null,"abstract":"We present a novel concept of longitudinal bunch train compression that can manipulate a relativistic electron beam across hundreds of meters. This concept holds the potential to compress the electron beam produced by a conditional linear accelerator at a high ratio, elevating its power to a level comparable with large induction accelerators. The method employs the spiral motion of electrons in a uniform magnetic field to fold hundreds-of-meters-long trajectories into a compact setup. The interval between bunches can be fine-tuned by modulating their spiral movement. We explore this method with the particle dynamic simulation. Compared to setups of similar size, such as a chicane, our method can compress bunches at considerably larger scales. Consequently, it opens up new possibilities for generating high-power beams using compact devices at lower costs.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140598921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Field flattening concepts for linac cavities of the cross-barHtype","authors":"Ali M. Almomani, Ulrich Ratzinger","doi":"10.1103/physrevaccelbeams.27.040101","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.040101","url":null,"abstract":"The development of cross-bar H-type cavities (CH-DTL, <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi>H</mi><mn>21</mn></msub></mrow></math> mode) is ongoing to improve the technology of this attractive type of drift tube linac (DTL). In comparison with the conventional DTL, the H-type cavities can reach a higher effective field gradient and are competitive in shunt impedance at an energy range up to 100 A MeV. H-mode DTL’s profit in shunt impedance additionally when applying the KONUS beam dynamics. They are in use at research laboratories as well as at hospitals. This paper describes a new concept to approach the zero mode in CH-type cavities, by extending the cavity diameter at the tank ends in combination with tilted drift tube stems. RFQs of the four-vane type are operated as well in the <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi mathvariant=\"normal\">H</mi><mn>210</mn></msub></mrow></math> mode and the strategy for voltage flattening can be partly applied there too if conventional vane undercuts are causing problems. Up to around 35 MeV, it is attractive to integrate one or more triplet lenses into each cavity, as one KONUS section is relatively short and would not exploit the full rf power of 3 MW klystrons which are available above 300 MHz. Such a cavity is denoted as a coupled CH-cavity CCH. Three possible arrangements of those internal triplet lenses are discussed and are compared to each other. The operating modes as well as higher modes are then compared with a lens-free CH cavity, where the lens position was filled by ordinary drift tubes. As a result, it is shown that the rf behavior and resonance frequency for the higher harmonics of the frequency band are very similar for all four investigated arrays. This means, that the tuning behavior of the CCH cavity can be simply deduced from the lens-free CH cavity by replacing an even number of ordinary drift tubes (<math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi mathvariant=\"normal\">n</mi><mi>β</mi><mi>λ</mi></mrow></math>) with a lens-containing drift tube with adequate length and large outer diameter. This large drift tube itself oscillates like an Alvarez-type drift tube. rf simulations on a 30-gap CH cavity show that the reduction in shunt impedance is about 10% when installing a lens with length 2 beta lambda.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140599561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Collisional simulations of the modulator section in coherent electron cooling","authors":"A. Al Marzouk, B. Erdélyi","doi":"10.1103/physrevaccelbeams.27.044401","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.044401","url":null,"abstract":"The first section of any coherent electron cooling (CeC) system is the modulator, where the density of the electron beam is modulated by the copropagating ion beam. This density modulation is a result of Coulomb collisions between the individual particles of the two beams. The pairwise, stochastic part of the interactions impacts the overall performance of the CeC process. We present the first simulations of the density modulations of the electron beams from a collisional picture of the dynamics, considering the proof-of-principle CeC experiments at Brookhaven National Laboratory. These simulations were performed using PHAD, which is the first efficient, large-scale collisional numerical method in beam physics that we have previously developed and benchmarked. Realistic beam distributions and external fields have been optimized to provide strong modulation signals necessary for variations of coherent electron cooling systems. Cooling performance limits and potential collisionless simulation pitfalls are pointed out.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140598913","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Specification and design for full energy beam exploitation of the compact linear accelerator for research and applications","authors":"E. W. Snedden, D. Angal-Kalinin, A. R. Bainbridge, A. D. Brynes, S. R. Buckley, D. J. Dunning, J. R. Henderson, J. K. Jones, K. J. Middleman, T. J. Overton, T. H. Pacey, A. E. Pollard, Y. M. Saveliev, B. J. A. Shepherd, P. H. Williams, M. I. Colling, B. D. Fell, G. Marshall","doi":"10.1103/physrevaccelbeams.27.041602","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.041602","url":null,"abstract":"The compact linear accelerator for research and applications (CLARA) is a 250 MeV ultrabright electron beam test facility at STFC Daresbury Laboratory. A user beamline has been designed to maximize the exploitation of CLARA in a variety of fields, including novel acceleration and new modalities of radiotherapy. In this paper, we present the specification and design of this beamline for full energy beam exploitation. We outline the key elements that will provide users access to ultrashort, low emittance electron bunches in two large experiment chambers. The results of start-to-end simulations are reported that verify the expected beam parameters delivered to these chambers. Key technical systems are detailed, including those which facilitate a combination of electron bunches with high-power laser pulses.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140598943","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"rf chopper for prebunched radioactive ion beams","authors":"A. Gonzalez, A. Plastun, P. N. Ostroumov","doi":"10.1103/physrevaccelbeams.27.041601","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.041601","url":null,"abstract":"An rf chopper system is being designed for the ReAccelerator (ReA) linac at the Facility for Rare Isotope Beams at Michigan State University. The 80.5 MHz ReA radio-frequency quadrupole accelerates prebunched 16.1 MHz beams, producing four satellite bunches for every main bunch. The chopper system includes an rf deflector that kicks every bunch vertically to spatially separate main and satellite bunches. A constant magnetic field superimposed with the chopper electric field biases the beam trajectory to ensure the high-intensity bunches do not experience a net deflection and are injected straight to the ReA6 cryomodule or sent for experiments. The kicked bunches are low in intensity and will be sent to a beam dump, resulting in a clean 16.1 MHz beam structure, which allows for a reliable time-of-flight separation of the isotopes.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140602105","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Erratum: Genetic algorithm enhanced by machine learning in dynamic aperture optimization [Phys. Rev. Accel. Beams21, 054601 (2018)]","authors":"Yongjun Li, Weixing Cheng, Li Hua Yu, Robert Rainer","doi":"10.1103/physrevaccelbeams.27.049901","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.049901","url":null,"abstract":"<span>DOI:</span><span>https://doi.org/10.1103/PhysRevAccelBeams.27.049901</span>","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140599479","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Beam dynamics driven design of powerful energy recovery linac for experiments","authors":"S. A. Bogaczet al.","doi":"10.1103/physrevaccelbeams.27.031603","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.031603","url":null,"abstract":"Powerful ERL for experiments (PERLE) is a novel energy recovery linac (ERL) test facility [1], designed to validate choices for a 50 GeV ERL foreseen in the design of the Large Hadron Electron Collider and the Future Circular Collider and to host dedicated nuclear and particle physics experiments. Its main goal is to demonstrate the high current, continuous wave, multipass operation with superconducting cavities at 802 MHz. With very high beam power (10 MW), PERLE offers an opportunity for controllable study of every beam dynamic effect of interest in the next generation of ERLs and becomes a “stepping stone” between the present state-of-the-art 1 MW ERLs and the future 100 MW scale applications.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140302503","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}