Pub Date : 2024-09-19DOI: 10.1103/physrevaccelbeams.27.094002
Bernard Riemann, Masamitsu Aiba, Jonas Kallestrup, Andreas Streun
New algorithms useful for the calculation of dynamic aperture and momentum acceptance in circular accelerators, particularly synchrotron light sources, are developed and presented. The flood-fill tool from raster graphics inspired us to efficiently compute dynamic apertures by minimizing required trackings on stable initial coordinates, leading to several factors of speedup with respect to standard algorithms. A novel technique for momentum acceptance calculations, Fast Touschek Tracking, is developed. Thorough benchmarking using modern accelerator codes shows that the new technique can provide one or two orders of magnitude faster computation of local momentum acceptances with only limited loss of accuracy.
{"title":"Efficient algorithms for dynamic aperture and momentum acceptance calculation in synchrotron light sources","authors":"Bernard Riemann, Masamitsu Aiba, Jonas Kallestrup, Andreas Streun","doi":"10.1103/physrevaccelbeams.27.094002","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.094002","url":null,"abstract":"New algorithms useful for the calculation of dynamic aperture and momentum acceptance in circular accelerators, particularly synchrotron light sources, are developed and presented. The flood-fill tool from raster graphics inspired us to efficiently compute dynamic apertures by minimizing required trackings on stable initial coordinates, leading to several factors of speedup with respect to standard algorithms. A novel technique for momentum acceptance calculations, Fast Touschek Tracking, is developed. Thorough benchmarking using modern accelerator codes shows that the new technique can provide one or two orders of magnitude faster computation of local momentum acceptances with only limited loss of accuracy.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"39 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142259684","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}
Pub Date : 2024-09-18DOI: 10.1103/physrevaccelbeams.27.094201
Zihang Zhao, Na Wang, Haisheng Xu, Zhilong Pan
Space-charge tune shifts can affect the beam quality in storage rings. Laslett’s method, a classical approach for calculating space-charge tune shifts, may not hold valid assumptions for rings with extremely short bunches and small bunch spacing, such as in steady-state microbunching (SSMB) storage rings. To overcome this limitation, we have developed new formulas that are suitable for arbitrary bunch lengths and spacings for calculating space-charge tune shifts. Additionally, simplified formulas have been provided for the calculations of space-charge tune shifts specifically in the context of extremely short bunch lengths. Numerical computations were carried out to demonstrate the validity of these newly derived formulas. Moreover, the formulas were applied to compute the space-charge tune shifts in an SSMB storage ring characterized by typical parameters.
{"title":"Calculations of space-charge tune shifts in storage rings with extremely short bunches and small bunch spacing","authors":"Zihang Zhao, Na Wang, Haisheng Xu, Zhilong Pan","doi":"10.1103/physrevaccelbeams.27.094201","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.094201","url":null,"abstract":"Space-charge tune shifts can affect the beam quality in storage rings. Laslett’s method, a classical approach for calculating space-charge tune shifts, may not hold valid assumptions for rings with extremely short bunches and small bunch spacing, such as in steady-state microbunching (SSMB) storage rings. To overcome this limitation, we have developed new formulas that are suitable for arbitrary bunch lengths and spacings for calculating space-charge tune shifts. Additionally, simplified formulas have been provided for the calculations of space-charge tune shifts specifically in the context of extremely short bunch lengths. Numerical computations were carried out to demonstrate the validity of these newly derived formulas. Moreover, the formulas were applied to compute the space-charge tune shifts in an SSMB storage ring characterized by typical parameters.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"29 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142259683","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}
Pub Date : 2024-09-18DOI: 10.1103/physrevaccelbeams.27.090101
B. Dhital, Y. S. Derbenev, A. Hutton, H. Zhang, G. A. Krafft, Y. Zhang, F. Lin, V. S. Morozov
A dual-energy electron storage ring is a novel concept initially proposed to cool hadron beams at high energies. The design consists of two closed rings operating at significantly different energies: the low-energy ring and the high-energy ring. These two rings are connected by an energy recovery linac (ERL) that provides the necessary energy difference. The ERL features superconducting radio-frequency (SRF) cavities that first accelerate the beam from the low energy to the high energy and then decelerate the beam from to in the next pass. The different SRF cavities in the ERL section can be adjusted based on the applications. In this paper, we present a possible layout of a dual-energy electron storage ring. The preliminary optics of the ring is designed to optimize chromaticity correction, dynamic aperture, momentum aperture, beam lifetime, radiation damping, and intrabeam scattering effects. The primary focus of this paper is on the stability conditions and beam dynamics studies associated with this storage ring.
{"title":"Dual-energy electron storage ring","authors":"B. Dhital, Y. S. Derbenev, A. Hutton, H. Zhang, G. A. Krafft, Y. Zhang, F. Lin, V. S. Morozov","doi":"10.1103/physrevaccelbeams.27.090101","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.090101","url":null,"abstract":"A dual-energy electron storage ring is a novel concept initially proposed to cool hadron beams at high energies. The design consists of two closed rings operating at significantly different energies: the low-energy ring and the high-energy ring. These two rings are connected by an energy recovery linac (ERL) that provides the necessary energy difference. The ERL features superconducting radio-frequency (SRF) cavities that first accelerate the beam from the low energy <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>E</mi><mi>L</mi></msub></math> to the high energy <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>E</mi><mi>H</mi></msub></math> and then decelerate the beam from <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>E</mi><mi>H</mi></msub></math> to <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>E</mi><mi>L</mi></msub></math> in the next pass. The different SRF cavities in the ERL section can be adjusted based on the applications. In this paper, we present a possible layout of a dual-energy electron storage ring. The preliminary optics of the ring is designed to optimize chromaticity correction, dynamic aperture, momentum aperture, beam lifetime, radiation damping, and intrabeam scattering effects. The primary focus of this paper is on the stability conditions and beam dynamics studies associated with this storage ring.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"77 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142259682","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}
Pub Date : 2024-09-16DOI: 10.1103/physrevaccelbeams.27.094001
G. Russo, G. Franchetti, M. Giovannozzi, E. H. Maclean
Harmonic analysis has provided powerful tools to accurately determine the tune from turn-by-turn data originating from numerical simulations or beam measurements in circular accelerators and storage rings. Methods that have been developed since the 1990s are suitable for stationary signals, i.e., time series whose properties do not vary with time and are represented by stationary signals. However, it is common experience that accelerator physics is a rich source of time series in which the signal amplitude varies over time. Furthermore, the properties of the amplitude variation of the signal often contain essential information about the phenomena under consideration. In this paper, a novel approach is presented, suitable for determining the tune of a nonstationary signal, which is based on the use of the Hilbert transform. The accuracy of the proposed methods is assessed in detail, and an application to the analysis of beam data collected at the CERN Large Hadron Collider is presented and discussed in detail.
{"title":"Harmonic analysis of nonstationary signals with application to LHC beam measurements","authors":"G. Russo, G. Franchetti, M. Giovannozzi, E. H. Maclean","doi":"10.1103/physrevaccelbeams.27.094001","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.094001","url":null,"abstract":"Harmonic analysis has provided powerful tools to accurately determine the tune from turn-by-turn data originating from numerical simulations or beam measurements in circular accelerators and storage rings. Methods that have been developed since the 1990s are suitable for stationary signals, i.e., time series whose properties do not vary with time and are represented by stationary signals. However, it is common experience that accelerator physics is a rich source of time series in which the signal amplitude varies over time. Furthermore, the properties of the amplitude variation of the signal often contain essential information about the phenomena under consideration. In this paper, a novel approach is presented, suitable for determining the tune of a nonstationary signal, which is based on the use of the Hilbert transform. The accuracy of the proposed methods is assessed in detail, and an application to the analysis of beam data collected at the CERN Large Hadron Collider is presented and discussed in detail.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"49 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142259685","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}
Pub Date : 2024-09-13DOI: 10.1103/physrevaccelbeams.27.091301
A. Frazzitta, R. Pompili, A. R. Rossi
We present a new approach that demonstrates the deflection and guiding of relativistic electron beams over curved paths by means of the magnetic field generated in a plasma-discharge capillary. The active bending plasma (ABP) represents a promising solution that has been recently demonstrated with a proof of principle experiment. An ABP device consists of a curved capillary where large discharges (of the order of kA) are propagated in a plasma channel. Unlike conventional bending magnets, in which the field is constant over the bending plane, in the ABP, the azimuthal magnetic field generated by the discharge grows with the distance from the capillary axis. This features makes the device less affected by the beam chromatic dispersion so that it can be used to efficiently guide particle beams with non-negligible energy spreads. The study we present in the following aims to provide a theoretical basis of the main ABP features by presenting an analytical description of a single-particle motion and rms beam dynamics. The retrieved relationships are verified by means of numerical simulations and provide the theoretical matrix formalism needed to completely characterize such a new transport device.
{"title":"Theory of particle beams transport over curved plasma-discharge capillaries","authors":"A. Frazzitta, R. Pompili, A. R. Rossi","doi":"10.1103/physrevaccelbeams.27.091301","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.091301","url":null,"abstract":"We present a new approach that demonstrates the deflection and guiding of relativistic electron beams over curved paths by means of the magnetic field generated in a plasma-discharge capillary. The active bending plasma (ABP) represents a promising solution that has been recently demonstrated with a proof of principle experiment. An ABP device consists of a curved capillary where large discharges (of the order of kA) are propagated in a plasma channel. Unlike conventional bending magnets, in which the field is constant over the bending plane, in the ABP, the azimuthal magnetic field generated by the discharge grows with the distance from the capillary axis. This features makes the device less affected by the beam chromatic dispersion so that it can be used to efficiently guide particle beams with non-negligible energy spreads. The study we present in the following aims to provide a theoretical basis of the main ABP features by presenting an analytical description of a single-particle motion and rms beam dynamics. The retrieved relationships are verified by means of numerical simulations and provide the theoretical matrix formalism needed to completely characterize such a new transport device.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"64 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142177723","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}
Pub Date : 2024-09-12DOI: 10.1103/physrevaccelbeams.27.092801
Zhi Song, Shiyu Zhou, Jianfei Hua, Yingchao Du, Fei Li, Bo Peng, Wei Lu, Zhen Wang
Beam-driven plasma wakefield acceleration (PWFA) is a promising technique to generate high-energy electron bunches for future electron-positron colliders. Longitudinal shaping of high-charge drive beam is highly desired for achieving high-transformer ratio and loading high-charge witness beam. However, the existing shaping schemes either focused on relatively low-charge bunch shaping or accompanied with significant charge-loss rate (typically over 50%). In this paper, a coherent-synchrotron-radiation-free shaping scheme based on velocity modulation is proposed to generate a high-charge beam with a linearly ramped profile. A -peak-current shaped beam containing charge with a low charge-loss rate is demonstrated by a start-to-end simulation, and the tunabilities of the beam charge and the peak current, and the robustness of the proposed shaping scheme are also discussed. When loaded by a 3 nC witness beam, a accelerating electric field with a transformer ratio larger than 4 can be achieved in a uniform plasma for the shaped drive beam, providing the possibility of high-transformer-ratio PWFA for a high-charge beam.
{"title":"Coherent-synchrotron-radiation-free longitudinal shaping of a high-charge electron bunch based on velocity modulation","authors":"Zhi Song, Shiyu Zhou, Jianfei Hua, Yingchao Du, Fei Li, Bo Peng, Wei Lu, Zhen Wang","doi":"10.1103/physrevaccelbeams.27.092801","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.092801","url":null,"abstract":"Beam-driven plasma wakefield acceleration (PWFA) is a promising technique to generate high-energy electron bunches for future electron-positron colliders. Longitudinal shaping of high-charge drive beam is highly desired for achieving high-transformer ratio and loading high-charge witness beam. However, the existing shaping schemes either focused on relatively low-charge bunch shaping or accompanied with significant charge-loss rate (typically over 50%). In this paper, a coherent-synchrotron-radiation-free shaping scheme based on velocity modulation is proposed to generate a high-charge beam with a linearly ramped profile. A <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mo form=\"prefix\" stretchy=\"false\">></mo><mn>10</mn><mtext> </mtext><mtext> </mtext><mi>kA</mi></mrow></math>-peak-current shaped beam containing <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mo form=\"prefix\">></mo><mn>50</mn><mtext> </mtext><mtext> </mtext><mi>nC</mi></math> charge with a low charge-loss rate is demonstrated by a start-to-end simulation, and the tunabilities of the beam charge and the peak current, and the robustness of the proposed shaping scheme are also discussed. When loaded by a 3 nC witness beam, a <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mo form=\"prefix\">></mo><mi>GV</mi><mo>/</mo><mi mathvariant=\"normal\">m</mi></math> accelerating electric field with a transformer ratio larger than 4 can be achieved in a uniform plasma for the shaped drive beam, providing the possibility of high-transformer-ratio PWFA for a high-charge beam.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"7 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142177722","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}
Pub Date : 2024-09-11DOI: 10.1103/physrevaccelbeams.27.094601
Ryan Roussel, Juan Pablo Gonzalez-Aguilera, Eric Wisniewski, Alexander Ody, Wanming Liu, John Power, Young-Kee Kim, Auralee Edelen
Next-generation accelerator concepts, which hinge on the precise shaping of beam distributions, demand equally precise diagnostic methods capable of reconstructing beam distributions within six-dimensional position-momentum spaces. However, the characterization of intricate features within six-dimensional beam distributions using current diagnostic techniques necessitates a substantial number of measurements, using many hours of valuable beam time. Novel phase space reconstruction techniques are needed to reduce the number of measurements required to reconstruct detailed, high-dimensional beam features in order to resolve complex beam phenomena and as a feedback in precision beam shaping applications. In this study, we present a novel approach to reconstructing detailed six-dimensional phase space distributions from experimental measurements using generative machine learning and differentiable beam dynamics simulations. We demonstrate that this approach can be used to resolve six-dimensional phase space distributions from scratch, using basic beam manipulations and as few as 20 two-dimensional measurements of the beam profile. We also demonstrate an application of the reconstruction method in an experimental setting at the Argonne Wakefield Accelerator, where it is able to reconstruct the beam distribution and accurately predict previously unseen measurements faster than previous methods.
{"title":"Efficient six-dimensional phase space reconstructions from experimental measurements using generative machine learning","authors":"Ryan Roussel, Juan Pablo Gonzalez-Aguilera, Eric Wisniewski, Alexander Ody, Wanming Liu, John Power, Young-Kee Kim, Auralee Edelen","doi":"10.1103/physrevaccelbeams.27.094601","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.094601","url":null,"abstract":"Next-generation accelerator concepts, which hinge on the precise shaping of beam distributions, demand equally precise diagnostic methods capable of reconstructing beam distributions within six-dimensional position-momentum spaces. However, the characterization of intricate features within six-dimensional beam distributions using current diagnostic techniques necessitates a substantial number of measurements, using many hours of valuable beam time. Novel phase space reconstruction techniques are needed to reduce the number of measurements required to reconstruct detailed, high-dimensional beam features in order to resolve complex beam phenomena and as a feedback in precision beam shaping applications. In this study, we present a novel approach to reconstructing detailed six-dimensional phase space distributions from experimental measurements using generative machine learning and differentiable beam dynamics simulations. We demonstrate that this approach can be used to resolve six-dimensional phase space distributions from scratch, using basic beam manipulations and as few as 20 two-dimensional measurements of the beam profile. We also demonstrate an application of the reconstruction method in an experimental setting at the Argonne Wakefield Accelerator, where it is able to reconstruct the beam distribution and accurately predict previously unseen measurements <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mn>75</mn><mo>×</mo></math> faster than previous methods.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"10 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142177724","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}
A light source project named very compact inverse Compton scattering gamma-ray source (VIGAS) is under development at Tsinghua University. VIGAS aims to generate monochromatic high-energy gamma rays by colliding 350-MeV electron beams with 400-nm laser photons within a 12-m beamline. To produce a high-energy electron beam in such a compact space, the system consists of an S-band high-brightness injector and six X-band high-gradient accelerating structures. The goal of the X-band structure is to operate at a high gradient of . Therefore, we adopts the constant gradient traveling wave approach, where the iris from the first cell to the end cell is tapered. The structure has 72 cells, including 70 cells and 2 couplers, so we named it XT72. The frequency of XT72 is selected to 11.424 GHz, and the mode is adopted. In this paper, we present a comprehensive study covering the detailed design, fabrication, rf tuning, and high-power test results of the first XT72. Additionally, we compare the performance of this structure to that of the previous constant impedance structure. Our results demonstrate that the XT72 is capable of operating at an gradient with a lower breakdown rate. This advancement paves the way for the development of VIGAS project and contributes to the wider application of X-band room-temperature high-gradient structures in compact accelerator facilities.
{"title":"Design and test of an X-band constant gradient structure","authors":"Qiang Gao, Hao Zha, Jiaru Shi, Xiancai Lin, Yingchao Du, Boyuan Feng, Hongyu Li, Heng Deng, Fangjun Hu, Jian Gao, Qingzhu Li, Weihang Gu, Jiayang Liu, Wenhui Huang, Chuanxiang Tang, Huaibi Chen","doi":"10.1103/physrevaccelbeams.27.090401","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.090401","url":null,"abstract":"A light source project named very compact inverse Compton scattering gamma-ray source (VIGAS) is under development at Tsinghua University. VIGAS aims to generate monochromatic high-energy gamma rays by colliding 350-MeV electron beams with 400-nm laser photons within a 12-m beamline. To produce a high-energy electron beam in such a compact space, the system consists of an S-band high-brightness injector and six X-band high-gradient accelerating structures. The goal of the X-band structure is to operate at a high gradient of <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mn>80</mn><mtext> </mtext><mtext> </mtext><mi>MV</mi><mo>/</mo><mi mathvariant=\"normal\">m</mi></mrow></math>. Therefore, we adopts the constant gradient traveling wave approach, where the iris from the first cell to the end cell is tapered. The structure has 72 cells, including 70 cells and 2 couplers, so we named it XT72. The frequency of XT72 is selected to 11.424 GHz, and the <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mn>2</mn><mi>π</mi><mo>/</mo><mn>3</mn></math> mode is adopted. In this paper, we present a comprehensive study covering the detailed design, fabrication, rf tuning, and high-power test results of the first XT72. Additionally, we compare the performance of this structure to that of the previous constant impedance structure. Our results demonstrate that the XT72 is capable of operating at an <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mn>80</mn><mtext>−</mtext><mrow><mi>MV</mi><mo>/</mo><mi mathvariant=\"normal\">m</mi></mrow></mrow></math> gradient with a lower breakdown rate. This advancement paves the way for the development of VIGAS project and contributes to the wider application of X-band room-temperature high-gradient structures in compact accelerator facilities.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"152 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142177729","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}
Pub Date : 2024-09-03DOI: 10.1103/physrevaccelbeams.27.092001
Mattias McMullin, Philipp Kolb, Zhongyuan Yao, Robert Laxdal, Tobias Junginger
The surface resistance of superconducting radio frequency (SRF) cavities depends on the strength of the applied rf field. This field dependence is caused by a combination of intrinsic losses and the extrinsic thermal feedback (TFB) effect. To test theories of intrinsic field dependence, the extrinsic part must be compensated for when analyzing experimental data from SRF cavity tests. Performing this compensation requires knowing thermal parameters that describe heat flow in the cavity walls. The relevant thermal parameters have been measured in the case of superfluid helium, below 2.177 K, but no detailed measurements have yet been reported for cooling of niobium surfaces in normal fluid helium baths. Because of this, the impact of TFB on the field dependence at temperatures near 4.2 K is unknown. In the present study, we report measurements of normal fluid helium boiling from niobium surfaces and its dependence on the orientation of the boiling surface and bath temperature. These measurements are used to create a finite-element model of heat transfer in cavities from TRIUMF’s coaxial test program. This tool is then used to compensate for TFB when analyzing a range of datasets from this program. Results are presented showing that TFB has a weak impact for the temperatures of 2.0 and 4.2 K, where SRF cavities are usually operated, but it is an important effect at intermediate temperatures.
超导射频（SRF）空腔的表面电阻取决于外加射频场的强度。这种场依赖性是由内在损耗和外在热反馈（TFB）效应共同造成的。为了测试本征场依赖性理论，在分析 SRF 腔体测试的实验数据时，必须对外征部分进行补偿。进行这种补偿需要了解描述腔壁热流的热参数。相关的热参数已经在 2.177 K 以下的超流体氦中测量过，但还没有关于正常流体氦槽中铌表面冷却的详细测量报告。正因为如此，TFB 对温度接近 4.2 K 时的磁场依赖性的影响还不得而知。在本研究中，我们报告了铌表面正常流体氦沸腾的测量结果及其与沸腾表面方向和浴槽温度的关系。这些测量结果被用于创建 TRIUMF 同轴测试程序中空腔传热的有限元模型。然后，在分析该计划的一系列数据集时，使用该工具对 TFB 进行补偿。结果表明，TFB 对 SRF 型腔通常工作的 2.0 和 4.2 K 温度影响较小，但对中间温度的影响很大。
{"title":"Thermal feedback in coaxial superconducting radio frequency cavities","authors":"Mattias McMullin, Philipp Kolb, Zhongyuan Yao, Robert Laxdal, Tobias Junginger","doi":"10.1103/physrevaccelbeams.27.092001","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.092001","url":null,"abstract":"The surface resistance of superconducting radio frequency (SRF) cavities depends on the strength of the applied rf field. This field dependence is caused by a combination of intrinsic losses and the extrinsic thermal feedback (TFB) effect. To test theories of intrinsic field dependence, the extrinsic part must be compensated for when analyzing experimental data from SRF cavity tests. Performing this compensation requires knowing thermal parameters that describe heat flow in the cavity walls. The relevant thermal parameters have been measured in the case of superfluid helium, below 2.177 K, but no detailed measurements have yet been reported for cooling of niobium surfaces in normal fluid helium baths. Because of this, the impact of TFB on the field dependence at temperatures near 4.2 K is unknown. In the present study, we report measurements of normal fluid helium boiling from niobium surfaces and its dependence on the orientation of the boiling surface and bath temperature. These measurements are used to create a finite-element model of heat transfer in cavities from TRIUMF’s coaxial test program. This tool is then used to compensate for TFB when analyzing a range of datasets from this program. Results are presented showing that TFB has a weak impact for the temperatures of 2.0 and 4.2 K, where SRF cavities are usually operated, but it is an important effect at intermediate temperatures.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"3 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142177725","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: Acceleration of uranium beam to record power of 10.4 kW and observation of new isotopes at Facility for Rare Isotope Beams [Phys. Rev. Accel. beams 27, 060101 (2024)]","authors":"P. N. Ostroumovet al.","doi":"10.1103/physrevaccelbeams.27.089901","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.089901","url":null,"abstract":"<span>DOI:</span><span>https://doi.org/10.1103/PhysRevAccelBeams.27.089901</span>","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"108 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142177726","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}
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