Pub Date : 2024-06-04DOI: 10.1103/physrevaccelbeams.27.062801
T. Liao, C. Guo, X. L. Yan, X. Zhou, Y. M. Xing, M. Wang, Y. J. Yuan, Y. H. Zhang, X. H. Zhou, M. Zhang, W. W. Ge, H. Y. Jiao, Y. L. Jiang, L. J. Mao, R. J. Chen, C. Y. Fu, R. S. Mao, J. C. Yang, S. A. Litvinov, Yu. A. Litvinov
The measurement of betatron tunes is important in the studies of beam dynamics in circular accelerators. Here, we report a new method to extract the fractional tune values using revolution times of single ions stored for a few hundred turns in a heavy-ion storage ring utilizing a single time-of-flight detector. The experiment was done at the experimental Cooler Storage Ring (CSRe) in Lanzhou. The unbunched cocktail secondary beam was injected into the ring and allowed to coast without further excitation. Since the average number of simultaneously stored ions inside the 128.8 m-circumference ring was merely , the obtained tune values are considered to be incoherent. Given that the revolution time of an individual ion is related to its momentum, the chromaticity of the ring could be addressed. Moreover, the data indicate a possible beam mismatch in vertical direction at the injection into CSRe. The new method is developed for ultralow beam intensities and is thus a sensitive approach to tune measurements. Thanks to its simplicity, the method can straightforwardly be employed at other circular accelerators by applying the same detection approach.
{"title":"Incoherent tune measurement of an ion storage ring using single ions","authors":"T. Liao, C. Guo, X. L. Yan, X. Zhou, Y. M. Xing, M. Wang, Y. J. Yuan, Y. H. Zhang, X. H. Zhou, M. Zhang, W. W. Ge, H. Y. Jiao, Y. L. Jiang, L. J. Mao, R. J. Chen, C. Y. Fu, R. S. Mao, J. C. Yang, S. A. Litvinov, Yu. A. Litvinov","doi":"10.1103/physrevaccelbeams.27.062801","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.062801","url":null,"abstract":"The measurement of betatron tunes is important in the studies of beam dynamics in circular accelerators. Here, we report a new method to extract the fractional tune values using revolution times of single ions stored for a few hundred turns in a heavy-ion storage ring utilizing a single time-of-flight detector. The experiment was done at the experimental Cooler Storage Ring (CSRe) in Lanzhou. The unbunched cocktail secondary beam was injected into the ring and allowed to coast without further excitation. Since the average number of simultaneously stored ions inside the 128.8 m-circumference ring was merely <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mo>∼</mo><mn>20</mn></math>, the obtained tune values are considered to be incoherent. Given that the revolution time of an individual ion is related to its momentum, the chromaticity of the ring could be addressed. Moreover, the data indicate a possible beam mismatch in vertical direction <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mover accent=\"true\"><mi>y</mi><mo stretchy=\"false\">^</mo></mover></math> at the injection into CSRe. The new method is developed for ultralow beam intensities and is thus a sensitive approach to tune measurements. Thanks to its simplicity, the method can straightforwardly be employed at other circular accelerators by applying the same detection approach.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"72 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141258967","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 : 2024-05-30DOI: 10.1103/physrevaccelbeams.27.054501
Gianluca Janka, Zaher Salman, Andreas Suter, Thomas Prokscha, Maria Mendes Martins, Xiaojie Ni
The low-energy muon (LEM) beamline at the Paul Scherrer Institute currently stands as the world’s only facility providing a continuous beam of low-energy muons with keV energies for conducting muon spin rotation experiments on a nanometer depth scale in heterostructures and near a sample’s surface. As such, optimizing the beam quality to reach its full potential is of paramount importance. One of the ongoing efforts is dedicated to improving the already applied technique of single muon tagging through the detection of secondary electrons emerging from an ultrathin carbon foil. In this work, we present the results from installing a thinner foil with a nominal thickness of and compare its performance to that of the previously installed foil with a nominal thickness of . Our findings indicate improved beam quality, characterized by smaller beam spots, reduced energy loss and straggling of the muons, and enhanced tagging efficiency. Additionally, we introduce a method utilizing blue laser irradiation for cleaning the carbon foil, further improving and maintaining its characteristics.
{"title":"Improving the beam quality of the low-energy muon beamline at Paul Scherrer Institute: Characterization of ultrathin carbon foils","authors":"Gianluca Janka, Zaher Salman, Andreas Suter, Thomas Prokscha, Maria Mendes Martins, Xiaojie Ni","doi":"10.1103/physrevaccelbeams.27.054501","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.054501","url":null,"abstract":"The low-energy muon (LEM) beamline at the Paul Scherrer Institute currently stands as the world’s only facility providing a continuous beam of low-energy muons with keV energies for conducting muon spin rotation experiments on a nanometer depth scale in heterostructures and near a sample’s surface. As such, optimizing the beam quality to reach its full potential is of paramount importance. One of the ongoing efforts is dedicated to improving the already applied technique of single muon tagging through the detection of secondary electrons emerging from an ultrathin carbon foil. In this work, we present the results from installing a thinner foil with a nominal thickness of <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mn>0.5</mn><mtext> </mtext><mtext> </mtext><mi mathvariant=\"normal\">μ</mi><mi mathvariant=\"normal\">g</mi></mrow><mrow><mtext> </mtext><msup><mrow><mi>cm</mi></mrow><mrow><mo>−</mo><mn>2</mn></mrow></msup></mrow></math> and compare its performance to that of the previously installed foil with a nominal thickness of <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mrow><mn>2.0</mn><mtext> </mtext><mtext> </mtext><mi mathvariant=\"normal\">μ</mi><mi mathvariant=\"normal\">g</mi><mtext> </mtext></mrow><mrow><msup><mrow><mi>cm</mi></mrow><mrow><mo>−</mo><mn>2</mn></mrow></msup></mrow></mrow></math>. Our findings indicate improved beam quality, characterized by smaller beam spots, reduced energy loss and straggling of the muons, and enhanced tagging efficiency. Additionally, we introduce a method utilizing blue laser irradiation for cleaning the carbon foil, further improving and maintaining its characteristics.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"49 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141189800","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 : 2024-05-30DOI: 10.1103/physrevaccelbeams.27.051303
Sophie Crisp, Alexander Ody, Joel England, Pietro Musumeci
The development of long, tunable structures is critical to increasing energy gain in laser-driven dielectric accelerators (DLAs). Here we combine pulse-front-tilt illumination with slab-geometry structures assembled by precisely aligning off-the-shelf 4 mm long transmission gratings to achieve up to 200 keV energy modulation for 6 MeV injected electrons. The effective interaction length is longer than 1 mm, limited by the dephasing of the accelerated particles in the structure. The piezo-based independent mounting system for the gratings allows tuning of the gap and field distribution inside the structure.
{"title":"Extended interaction length laser-driven acceleration in a tunable dielectric structure","authors":"Sophie Crisp, Alexander Ody, Joel England, Pietro Musumeci","doi":"10.1103/physrevaccelbeams.27.051303","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.051303","url":null,"abstract":"The development of long, tunable structures is critical to increasing energy gain in laser-driven dielectric accelerators (DLAs). Here we combine pulse-front-tilt illumination with slab-geometry structures assembled by precisely aligning off-the-shelf 4 mm long transmission gratings to achieve up to 200 keV energy modulation for 6 MeV injected electrons. The effective interaction length is longer than 1 mm, limited by the dephasing of the accelerated particles in the structure. The piezo-based independent mounting system for the gratings allows tuning of the gap and field distribution inside the structure.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"2010 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141190025","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 : 2024-05-28DOI: 10.1103/physrevaccelbeams.27.054601
Jan Kaiser, Chenran Xu, Annika Eichler, Andrea Santamaria Garcia
Machine learning has emerged as a powerful solution to the modern challenges in accelerator physics. However, the limited availability of beam time, the computational cost of simulations, and the high dimensionality of optimization problems pose significant challenges in generating the required data for training state-of-the-art machine learning models. In this work, we introduce cheetah, a pytorch-based high-speed differentiable linear beam dynamics code. cheetah enables the fast collection of large datasets by reducing computation times by multiple orders of magnitude and facilitates efficient gradient-based optimization for accelerator tuning and system identification. This positions cheetah as a user-friendly, readily extensible tool that integrates seamlessly with widely adopted machine learning tools. We showcase the utility of cheetah through five examples, including reinforcement learning training, gradient-based beamline tuning, gradient-based system identification, physics-informed Bayesian optimization priors, and modular neural network surrogate modeling of space charge effects. The use of such a high-speed differentiable simulation code will simplify the development of machine learning-based methods for particle accelerators and fast-track their integration into everyday operations of accelerator facilities.
{"title":"Bridging the gap between machine learning and particle accelerator physics with high-speed, differentiable simulations","authors":"Jan Kaiser, Chenran Xu, Annika Eichler, Andrea Santamaria Garcia","doi":"10.1103/physrevaccelbeams.27.054601","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.054601","url":null,"abstract":"Machine learning has emerged as a powerful solution to the modern challenges in accelerator physics. However, the limited availability of beam time, the computational cost of simulations, and the high dimensionality of optimization problems pose significant challenges in generating the required data for training state-of-the-art machine learning models. In this work, we introduce <span>c</span>heetah, a <span>p</span>y<span>t</span>orch-based high-speed differentiable linear beam dynamics code. <span>c</span>heetah enables the fast collection of large datasets by reducing computation times by multiple orders of magnitude and facilitates efficient gradient-based optimization for accelerator tuning and system identification. This positions <span>c</span>heetah as a user-friendly, readily extensible tool that integrates seamlessly with widely adopted machine learning tools. We showcase the utility of <span>c</span>heetah through five examples, including reinforcement learning training, gradient-based beamline tuning, gradient-based system identification, physics-informed Bayesian optimization priors, and modular neural network surrogate modeling of space charge effects. The use of such a high-speed differentiable simulation code will simplify the development of machine learning-based methods for particle accelerators and fast-track their integration into everyday operations of accelerator facilities.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"69 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141168295","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 : 2024-05-28DOI: 10.1103/physrevaccelbeams.27.052901
S. Benítez, B. Salvachúa, M. Chen
Cherenkov optical beam loss monitors (oBLMs) based on optical fibers are a revolutionary achievement among the monitoring systems in particle accelerators. Due to the nature of the Cherenkov phenomenon and the intrinsic characteristics of optical fibers, the photon production and fiber light transmission need to be studied to deduce the total amount of Cherenkov photons detected by the photosensors attached at the end of the system. Simulations of the Cherenkov oBLM detector system have been implemented using the fluka software with postprocessing considering the light attenuation and capture factors in the optical fiber. In addition, the study includes the longitudinal beam loss localization of the controlled beam losses produced along the CERN Linear Electron Accelerator for Research (CLEAR) test facility line. In this paper, the Cherenkov photon detection by an oBLM installed in the CLEAR facility is simulated, analyzed, and compared with experimental data.
{"title":"Beam loss detection based on generation of Cherenkov light in optical fibers in the CERN Linear Electron Accelerator for Research","authors":"S. Benítez, B. Salvachúa, M. Chen","doi":"10.1103/physrevaccelbeams.27.052901","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.052901","url":null,"abstract":"Cherenkov optical beam loss monitors (oBLMs) based on optical fibers are a revolutionary achievement among the monitoring systems in particle accelerators. Due to the nature of the Cherenkov phenomenon and the intrinsic characteristics of optical fibers, the photon production and fiber light transmission need to be studied to deduce the total amount of Cherenkov photons detected by the photosensors attached at the end of the system. Simulations of the Cherenkov oBLM detector system have been implemented using the <span>fluka</span> software with postprocessing considering the light attenuation and capture factors in the optical fiber. In addition, the study includes the longitudinal beam loss localization of the controlled beam losses produced along the CERN Linear Electron Accelerator for Research (CLEAR) test facility line. In this paper, the Cherenkov photon detection by an oBLM installed in the CLEAR facility is simulated, analyzed, and compared with experimental data.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"53 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141173447","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 : 2024-05-28DOI: 10.1103/physrevaccelbeams.27.051601
L. Valle, T. Brochard, N. Carmignani, L. R. Carver, J. Chavanne, F. Ewald, G. Le Bec, S. M. Liuzzo, T. Perron, J. Reyes-Herrera, P. Raimondi, K. Scheidt, R. Versteegen, J. Wade, S. White
The European Synchrotron Radiation Facility Extremely Brilliant Source (ESRF-EBS) is the first fourth generation 6 GeV storage ring (SR) light source making use of the hybrid multibend achromat lattice, reaching a natural horizontal emittance of 140 pm rad. Further, reducing the horizontal emittance would provide a more brilliant and a higher quality photon source for the EBS users. One way of achieving this is to operate the SR off-energy. The first approach reduces the electron beam energy by , which gives a 121 pm rad natural horizontal emittance. To fulfill operation requirements, the full ring had to be rematched, including both the quadrupoles and the sextupoles in the linear optics correction. The off-energy settings are then tested in the SR in terms of lifetime, injection efficiency, and operability.
欧洲同步辐射设施极灿烂光源（ESRF-EBS）是首个使用混合多弯消色差晶格的第四代 6 GeV 储存环（SR）光源，其自然水平发射率达到 140 pm rad。此外，降低水平发射率将为 EBS 用户提供更明亮、更高质量的光子源。实现这一目标的方法之一是使 SR 脱离能量运行。第一种方法是将电子束能量降低-1%，从而获得 121 pm rad 的自然水平发射率。为了满足运行要求，必须重新匹配整个环，包括线性光学校正中的四极和六极。然后在 SR 中对非能量设置进行寿命、注入效率和可操作性方面的测试。
{"title":"Off-energy operation for the Extremely Brilliant Source at the European Synchrotron Radiation Facility","authors":"L. Valle, T. Brochard, N. Carmignani, L. R. Carver, J. Chavanne, F. Ewald, G. Le Bec, S. M. Liuzzo, T. Perron, J. Reyes-Herrera, P. Raimondi, K. Scheidt, R. Versteegen, J. Wade, S. White","doi":"10.1103/physrevaccelbeams.27.051601","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.051601","url":null,"abstract":"The European Synchrotron Radiation Facility Extremely Brilliant Source (ESRF-EBS) is the first fourth generation 6 GeV storage ring (SR) light source making use of the hybrid multibend achromat lattice, reaching a natural horizontal emittance of 140 pm rad. Further, reducing the horizontal emittance would provide a more brilliant and a higher quality photon source for the EBS users. One way of achieving this is to operate the SR off-energy. The first approach reduces the electron beam energy by <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mo>−</mo><mn>1</mn><mo>%</mo></math>, which gives a 121 pm rad natural horizontal emittance. To fulfill operation requirements, the full ring had to be rematched, including both the quadrupoles and the sextupoles in the linear optics correction. The off-energy settings are then tested in the SR in terms of lifetime, injection efficiency, and operability.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"62 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141167867","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 : 2024-05-24DOI: 10.1103/physrevaccelbeams.27.051302
D. Storeyet al.
Plasma wakefield acceleration provides ultrahigh acceleration gradients of tens of GeV/m, providing a novel path toward efficient, compact, TeV-scale linear colliders, and high brightness free electron lasers. Critical to the success of these applications is demonstrating simultaneously high gradient acceleration, high energy transfer efficiency, and preservation of emittance, charge, and energy spread. Experiments at the FACET-II National User Facility at SLAC National Accelerator Laboratory aim to achieve all of these milestones in a single-stage plasma wakefield accelerator, providing a 10 GeV energy gain in a plasma with high energy transfer efficiency. Such a demonstration depends critically on diagnostics able to measure emittance with mm mrad accuracy, energy spectra to determine both percent level energy spread, and broadband energy gain and loss, incoming longitudinal phase space, and matching dynamics. This paper discusses the experimental setup at FACET-II, including the incoming beam parameters from the FACET-II linac, plasma sources, and diagnostics developed to meet this challenge. Initial progress on the generation of beam ionized wakes in meter-scale hydrogen gas is discussed as well as commissioning of the plasma sources and diagnostics.
{"title":"Wakefield generation in hydrogen and lithium plasmas at FACET-II: Diagnostics and first beam-plasma interaction results","authors":"D. Storeyet al.","doi":"10.1103/physrevaccelbeams.27.051302","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.051302","url":null,"abstract":"Plasma wakefield acceleration provides ultrahigh acceleration gradients of tens of GeV/m, providing a novel path toward efficient, compact, TeV-scale linear colliders, and high brightness free electron lasers. Critical to the success of these applications is demonstrating simultaneously high gradient acceleration, high energy transfer efficiency, and preservation of emittance, charge, and energy spread. Experiments at the FACET-II National User Facility at SLAC National Accelerator Laboratory aim to achieve all of these milestones in a single-stage plasma wakefield accelerator, providing a 10 GeV energy gain in a <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mo form=\"prefix\"><</mo><mn>1</mn><mtext> </mtext><mtext> </mtext><mi mathvariant=\"normal\">m</mi></math> plasma with high energy transfer efficiency. Such a demonstration depends critically on diagnostics able to measure emittance with mm mrad accuracy, energy spectra to determine both percent level energy spread, and broadband energy gain and loss, incoming longitudinal phase space, and matching dynamics. This paper discusses the experimental setup at FACET-II, including the incoming beam parameters from the FACET-II linac, plasma sources, and diagnostics developed to meet this challenge. Initial progress on the generation of beam ionized wakes in meter-scale hydrogen gas is discussed as well as commissioning of the plasma sources and diagnostics.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"31 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141146423","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":"Editorial: Coauthor! Coauthor!","authors":"Randall D. Kamien, Daniel Ucko","doi":"10.1103/physrevaccelbeams.27.050001","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.050001","url":null,"abstract":"<span>DOI:</span><span>https://doi.org/10.1103/PhysRevAccelBeams.27.050001</span>","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"44 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141146422","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 : 2024-05-20DOI: 10.1103/physrevaccelbeams.27.052803
F. C. Salgado, A. Kozan, D. Seipt, D. Hollatz, P. Hilz, M. Kaluza, A. Sävert, A. Seidel, D. Ullmann, Y. Zhao, M. Zepf
Novel schemes for generating ultralow emittance electron beams have been developed in past years and promise compact particle sources with excellent beam quality suitable for future high-energy physics experiments and free-electron lasers. Recent theoretical work has proposed a laser-based method capable of resolving emittances in the sub 0.1 mm mrad regime by modulating the electron phase space ponderomotively. Here we present the first experimental demonstration of this scheme using a laser wakefield accelerator. The observed emittance and source size are consistent with published values. We also show calculations demonstrating that tight bounds on the upper limit for emittance and source size can be derived from the “laser-grating” method even in the presence of low signal to noise and uncertainty in laser-grating parameters.
在过去几年中，已经开发出了用于产生超低发射率电子束的新方案，这些方案有望成为适合未来高能物理实验和自由电子激光器的具有优异光束质量的紧凑型粒子源。最近的理论工作提出了一种基于激光的方法，能够通过调制电子相空间的思索动量来分辨低于 0.1 mm mrad 的发射率。在这里，我们首次利用激光汪场加速器对这一方案进行了实验演示。观测到的发射率和光源大小与已公布的数值一致。我们还展示了计算结果，证明即使在低信噪比和激光光栅参数不确定的情况下，也可以通过 "激光光栅 "方法得出发射率和光源尺寸的严格上限。
{"title":"All-optical source size and emittance measurements of laser-accelerated electron beams","authors":"F. C. Salgado, A. Kozan, D. Seipt, D. Hollatz, P. Hilz, M. Kaluza, A. Sävert, A. Seidel, D. Ullmann, Y. Zhao, M. Zepf","doi":"10.1103/physrevaccelbeams.27.052803","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.052803","url":null,"abstract":"Novel schemes for generating ultralow emittance electron beams have been developed in past years and promise compact particle sources with excellent beam quality suitable for future high-energy physics experiments and free-electron lasers. Recent theoretical work has proposed a laser-based method capable of resolving emittances in the sub 0.1 mm mrad regime by modulating the electron phase space ponderomotively. Here we present the first experimental demonstration of this scheme using a laser wakefield accelerator. The observed emittance and source size are consistent with published values. We also show calculations demonstrating that tight bounds on the upper limit for emittance and source size can be derived from the “laser-grating” method even in the presence of low signal to noise and uncertainty in laser-grating parameters.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"10 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141146458","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 : 2024-05-20DOI: 10.1103/physrevaccelbeams.27.050702
Philipp Dijkstal, Weilun Qin, Sergey Tomin
Time-resolved diagnostics at free-electron laser (FEL) facilities, in particular electron beam longitudinal phase space (LPS) and FEL power profile measurements, provide information highly valuable for users, machine development studies, and beam setup. We investigate the slice energy resolution of passive streaker setups, in particular the effect of an energy chirp on the measured slice energy spread. Downstream of the hard x-ray SASE2 beamline at the European XFEL, these measurements are enabled by a single-plate nonmovable passive wakefield streaker, essentially a rectangular corrugated plate placed inside a vacuum chamber. We show measurements with a time resolution down to a few femtoseconds and an energy resolution down to a few MeVs.
自由电子激光（FEL）设备的时间分辨诊断，特别是电子束纵向相位空间（LPS）和FEL功率曲线测量，为用户、设备开发研究和光束设置提供了非常有价值的信息。我们研究了被动条纹器设置的切片能量分辨率，特别是能量啁啾对测量切片能量分布的影响。在欧洲 XFEL 的硬 X 射线 SASE2 光束线下游，这些测量由单板不可移动的被动式唤醒场条纹器实现，该条纹器基本上是一个放置在真空室中的矩形波纹板。我们展示了时间分辨率低至几飞秒、能量分辨率低至几 MeV 的测量结果。
{"title":"Longitudinal phase space diagnostics with a nonmovable corrugated passive wakefield streaker","authors":"Philipp Dijkstal, Weilun Qin, Sergey Tomin","doi":"10.1103/physrevaccelbeams.27.050702","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.050702","url":null,"abstract":"Time-resolved diagnostics at free-electron laser (FEL) facilities, in particular electron beam longitudinal phase space (LPS) and FEL power profile measurements, provide information highly valuable for users, machine development studies, and beam setup. We investigate the slice energy resolution of passive streaker setups, in particular the effect of an energy chirp on the measured slice energy spread. Downstream of the hard x-ray SASE2 beamline at the European XFEL, these measurements are enabled by a single-plate nonmovable passive wakefield streaker, essentially a rectangular corrugated plate placed inside a vacuum chamber. We show measurements with a time resolution down to a few femtoseconds and an energy resolution down to a few MeVs.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"30 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141146478","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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