Physical Review Accelerators and Beams最新文献

{"title":"Four-dimensional phase-space reconstruction of flat and magnetized beams using neural networks and differentiable simulations","authors":"Seongyeol Kim, Juan Pablo Gonzalez-Aguilera, Philippe Piot, Gongxiaohui Chen, Scott Doran, Young-Kee Kim, Wanming Liu, Charles Whiteford, Eric Wisniewski, Auralee Edelen, Ryan Roussel, John Power","doi":"10.1103/physrevaccelbeams.27.074601","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.074601","url":null,"abstract":"Beams with cross-plane coupling or extreme asymmetries between the two transverse phase spaces are often encountered in particle accelerators. Flat beams with large transverse-emittance ratios are critical for future linear colliders. Similarly, magnetized beams with significant cross-plane coupling are expected to enhance the performance of electron cooling in hadron beams. Preparing these beams requires precise control and characterization of the four-dimensional transverse phase space. In this study, we employ generative phase-space reconstruction techniques to rapidly characterize magnetized and flat-beam phase-space distributions using a conventional quadrupole-scan method. The reconstruction technique is experimentally demonstrated on an electron beam produced at the Argonne Wakefield Accelerator and successfully benchmarked against conventional diagnostics techniques. Specifically, we show that predicted beam parameters from the reconstructed phase-space distributions (e.g., as magnetization and flat-beam emittances) are in excellent agreement with those measured from the conventional diagnostic methods.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"18 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141745032","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":"Laser-driven acceleration of a 94.8 MeV uniform proton beam enhanced by a thin axial absorber rod","authors":"Husam Y. Al-Omari, Mohamed E. Yahia, Ali M. Almomani","doi":"10.1103/physrevaccelbeams.27.073501","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.073501","url":null,"abstract":"Laser-based proton accelerators offer promising advantages for many sensitive applications due to their compact size. However, achieving uniform beams with a narrow energy spread remains a challenge. Here, a beamline simulation is performed using the <span>t</span>race<span>w</span>in and <span>srim</span> codes to optimize the spectral and spatial characteristics of a laser-driven proton beam. This beamline, comprised of four magnetic quadrupoles and equipped with a thin axial absorber rod in conjunction with an energy selection aperture for narrowing the energy spread, a carbon scatterer foil for beam spot smoothing, and an angular selection aperture for beam collimation, effectively transports a selected proton beam energy within the range of 50–250 MeV. In this work, laser-accelerated protons with a wide energy spread were transported through the proposed beamline, which was optimized for 109 MeV protons. The protons emerged well-collimated with a significantly narrowed energy spread of <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mn>94.8</mn><mo>±</mo><mn>3.9</mn><mtext> </mtext><mtext> </mtext><mi>MeV</mi></math> (a reduction from the intended 109 MeV due to passage through the scatterer) and a homogenized, 11 mm diameter beam spot while maintaining a transmission efficiency above 2.2%.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"26 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141745030","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":"Wavelength scaling and multicolor operation of a plasma-driven attosecond x-ray source via harmonic generation","authors":"Rafi Hessami, Jenny Morgan, River Robles, Kirk A. Larsen, Agostino Marinelli, Claudio Emma","doi":"10.1103/physrevaccelbeams.27.070701","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.070701","url":null,"abstract":"The generation of high-power coherent soft x-ray pulses of sub-100 as duration and 10 nm wavelength using beams from a GeV energy plasma wakefield accelerator has been recently investigated in Emma <i>et al.</i> [<span>APL Photonics</span> <b>6</b>, 076107 (2021)]. As a future upgrade to this concept, this contribution investigates scaling to shorter x-ray wavelengths by cascading undulators tuned to higher harmonics of the fundamental. We present two simulation studies for plasma-driven attosecond harmonic generation schemes with final photon wavelengths of 2 and 0.40 nm. We demonstrate in these schemes that using undulators with retuned fundamental frequencies can produce GW-scale pulses of sub-nm radiation with tens of attosecond-scale pulse lengths, an order of magnitude shorter than current state-of-the-art attosecond x-ray free electron lasers (XFELs). This multipulse multicolor operation will be broadly applicable to attosecond pump-probe experiments.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"7 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141612277","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":"Empty-bucket techniques for spill-quality improvement at the CERN Super Proton Synchrotron","authors":"Pablo A. Arrutia Sota, Matthew A. Fraser, Gregoire Hagmann, Verena Kain, Giulia Papotti, Arthur Spierer, Francesco M. Velotti, Philip N. Burrows, Roberto Piandani","doi":"10.1103/physrevaccelbeams.27.074001","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.074001","url":null,"abstract":"Synchrotrons can provide long spills of particles by employing resonant extraction where the circulating beam is slowly ejected over thousands to millions of turns by exploiting the amplitude growth caused by a transverse resonance. In the CERN Super Proton Synchrotron (SPS), this method is used to satisfy the experimental requests of the North Area. However, the extracted particle flux is modulated by power-converter ripple, an issue shared across all sychrotrons that perform resonant extraction. In order to suppress such modulations, empty-bucket techniques can be employed, which take advantage of chromaticity to quickly accelerate particles into resonant motion by using a longitudinal rf system. This paper explores empty-bucket techniques via theory, simulation, and measurement, providing a systematic characterization with general applicability to any machine. Additionally, the operational implementation in the SPS is detailed, where the impact on the beam profile and extracted intensity is addressed.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"18 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141571044","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":"Numerical simulation of RHIC polarized proton run 17 spin flipper experiments","authors":"F. Méot, P. Adams, H. Huang, J. Kewisch, P. Oddo, T. Roser","doi":"10.1103/physrevaccelbeams.27.071002","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.071002","url":null,"abstract":"RHIC nine-magnet spin flipper has been operated successfully during RHIC polarized proton Run 17, with 97% spin flip efficiency achieved. The results show the importance of mirror resonance removal, small spin tune spread, and proper spin flipper driving tune sweep speed. Detailed spin tracking simulations, based on a Lorentz force and Thomas-BMT differential equation numerical solver code for accuracy, have been carried out to understand the experimental results. Agreement within measurement accuracy is obtained at injection energy, 23.8 GeV. It is not as tight at 255 GeV, reasons for that are exposed. These measurements and numerical studies allow to determine the sensitivity of spin-flip efficiency to the dispersion slopes at the two Siberian snakes and to the ac dipole frequency sweep speed. They also provide guidance for future developments at BNL’s electron-ion collider.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"26 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141570986","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":"Generalized threshold of longitudinal multibunch instability in synchrotrons","authors":"Ivan Karpov, Elena Shaposhnikova","doi":"10.1103/physrevaccelbeams.27.074401","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.074401","url":null,"abstract":"Beam stability is a crucial requirement for all particle accelerators. Coupled-bunch instability (CBI) is driven by beam interaction with narrowband impedance of the resonant accelerator components. Loss of Landau damping (LLD) for a single bunch is mainly determined by broadband impedance and can lead to undamped bunch oscillations. For the first time, we solve numerically the longitudinal stability problem in a self-consistent way for a general case of two impedance types and propose a simple analytical criterion describing how the obtained LLD and CBI thresholds are combined. We demonstrate that LLD can modify the CBI mechanism and reduce the instability threshold even below the LLD threshold. These findings allow the existing beam observations in CERN Super Proton Synchrotron and Large Hadron Collider to be explained and should be considered in design of the future accelerators.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"150 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141577665","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":"Impact of beam coupling impedance on crab cavity noise induced emittance growth","authors":"N. Triantafyllou, F. Antoniou, H. Bartosik, P. Baudrenghien, X. Buffat, R. Calaga, Y. Papaphilippou, T. Mastoridis, A. Wolski","doi":"10.1103/physrevaccelbeams.27.071001","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.071001","url":null,"abstract":"Crab cavities will be deployed as a part of the High Luminosity Large Hadron Collider (HL-LHC) upgrade to mitigate the luminosity reduction induced by the crossing angle at the main experiments (ATLAS and CMS). Two prototype crab cavities have been installed in the CERN Super Proton Synchrotron (SPS) in 2018 for studies with proton beams. An issue of concern is the transverse emittance growth induced by noise in the crab cavity radio frequency (rf) system, which is anticipated to limit the performance of the HL-LHC. In measurements conducted in the SPS in 2018, the crab cavity noise-induced emittance growth was measured to be a factor of 4 lower than predicted from the existing analytical models. In this paper, it is shown that the observed discrepancy is explained by damping effects from the beam coupling impedance, which were not included in the models up to now. Using the van Kampen mode approach, a new theory is developed, suggesting that the impedance can separate the coherent tune from the incoherent spectrum leading to an effective reduction of the crab cavity rf noise-induced emittance growth. This mechanism is validated in tracking simulations using the SPS impedance model as well as in dedicated experimental measurements conducted in the SPS in 2022. The implications for the HL-LHC project are discussed.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"43 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141570976","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":"5D tomographic phase-space reconstruction of particle bunches","authors":"S. Jaster-Merz, R. W. Assmann, R. Brinkmann, F. Burkart, W. Hillert, M. Stanitzki, T. Vinatier","doi":"10.1103/physrevaccelbeams.27.072801","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.072801","url":null,"abstract":"We propose a new beam diagnostics method to reconstruct the phase space of charged particle bunches in five dimensions, which consist of the horizontal and vertical positions and divergences as well as the time axis. This is achieved by combining a quadrupole-based transverse phase-space tomography with the adjustable streaking angle of a polarizable X-band transverse deflection structure. We demonstrate with detailed simulations that the method is able to reconstruct various complex phase-space distributions and that the quality of the reconstruction depends on the number of input projections. This method allows for the identification and visualization of previously unnoticed detailed features in the phase-space distribution and can thereby be used as a tool toward improving the performance of particle accelerators or performing more accurate simulation studies.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"44 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141553072","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 physics studies for a high charge and high beam quality laser-plasma accelerator","authors":"Samuel Marini, Damien F. G. Minenna, Francesco Massimo, Laury Batista, Vittorio Bencini, Antoine Chancé, Nicolas Chauvin, Steffen Doebert, John Farmer, Edda Gschwendtner, Ioaquin Moulanier, Patric Muggli, Didier Uriot, Brigitte Cros, Phu Anh Phi Nghiem","doi":"10.1103/physrevaccelbeams.27.063401","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.063401","url":null,"abstract":"Electron acceleration by laser-plasma techniques is approaching maturity and is getting ready for the construction of particle accelerators with dedicated applications. We present a general methodology showing how beam physics studies can be used to achieve a specific parameter set in a laser-plasma accelerator. Laser systems, plasma targets, and magnetic component properties are designed to optimize the electron beam so as to achieve the required performances. Beam physics in its full 6D phase space is studied from electron injection to beam delivery to the end user, through the plasma acceleration stage and transport line. As each beam parameter can only be modified by specific electric/magnetic field configurations, it is crucial to assign from the beginning specific roles to given accelerator sections in obtaining given beam parameters. These beam physics considerations were successfully applied to the design of a plasma-based electron injector for the AWAKE Run2 experiment. Electron beam parameters were calculated using a global simulation, achieving simultaneously unprecedented high charge (100 pC) and high quality (micrometric beam emittance and size).","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"16 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141553266","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":"Energy deposition studies for the Upgrade II of LHCb at the CERN Large Hadron Collider","authors":"Alessia Ciccotelli, Robert B. Appleby, Francesco Cerutti, Kevin Buffet, Francois Butin, Gloria Corti, Luigi Salvatore Esposito, Ruben Garcia Alia, Matthias Karacson, Giuseppe Lerner, Maud Wehrle, Daniel Prelipcean","doi":"10.1103/physrevaccelbeams.27.061003","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.061003","url":null,"abstract":"The Upgrade II of the Large Hadron Collider beauty (LHCb) experiment is proposed to be installed during the CERN Long Shutdown 4, aiming to operate LHCb at <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mn>1.5</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mn>34</mn></mrow></msup><mtext> </mtext><mtext> </mtext><msup><mrow><mi>cm</mi></mrow><mrow><mo>−</mo><mn>2</mn></mrow></msup><mtext> </mtext><msup><mrow><mi mathvariant=\"normal\">s</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math> that is 75 times its design luminosity [1] and reaching an integrated luminosity of about <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mn>400</mn><mtext> </mtext><mtext> </mtext><msup><mi>fb</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math> by the end of the High Luminosity LHC era. This increase of the data sample at LHCb is an unprecedented opportunity for heavy flavor physics measurements. A first upgrade of LHCb (Upgrade I), completed in 2022, has already implemented important changes of the LHCb detector and, for the Upgrade II, further detector improvements of the tracking system, the particle identification system and the online and trigger infrastructure are being considered. Such a luminosity increase will have an impact not only on the LHCb detector but also on the LHC magnets, cryogenics, and electronic equipment placed in the insertion region 8. In fact, the LHCb experiment was conceived to work at a much lower luminosity than ATLAS and CMS, implying minor requirements for protection of the LHC elements from the collision debris, and therefore, a different layout around the interaction point. The Upgrade I has already implied the installation of an absorber for the neutral particle debris (TANB). However, the luminosity target proposed for this second upgrade requires to review the layout of the entire insertion region in order to ensure safe operation of the LHC magnets and to mitigate the risk of failure of the electronic devices. The objective of this paper is to provide an overview of the implications of the Upgrade II of LHCb in the experimental cavern and in the tunnel with a focus on the LHCb detector, electronic devices, and accelerator magnets. This proves that the Upgrade II luminosity goal can be sustained with the implementation of protection systems for magnets and electronics. The electronics placed in the experimental areas and in the cavern needs to be protected to mitigate a single event effect risk, which may imply recurring downtime of the LHC. On the other hand, protection for the first quadrupole of the final focus triplet and for the separation dipole are needed to prevent their quench and to reach the desired lifetime. Moreover, the normal-conducting compensators require the installation of shielding to limit their head coil degradation.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"34 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141553280","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}