Physical Review Accelerators and Beams最新文献

{"title":"Analytical analysis of the generation of a rotating driving magnetic field on the outer surface of a magnetic pinch load with a helical return current post","authors":"Shu-Chao Duan, Ge-Guang He, Shao-Tong Zhou, Ming-Xian Kan, Gang-Hua Wang","doi":"10.1103/physrevaccelbeams.27.030401","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.030401","url":null,"abstract":"A recently emerging approach adopts a directionally time-varying (rotating) magnetic field to drive a pinch load, aiming to mitigate the inherent magneto-Rayleigh-Taylor instability in dynamic <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>Z</mi></mrow></math> pinches. A helical return current post (RCP) serves as a functional structural element capable of generating the requisite driving magnetic field for this purpose in the load region. This paper first calculates the current azimuthally induced on the outer surface of a magnetically pinched load within this type of RCP using a zero-dimensional lumped-parameter circuit model. The results show that the induced current deviates significantly from the presumed “perfect” induced current (100% amplitude) as reported in the literature [S. A. Sorokin, <span>Plasma Phys. Rep.</span> <b>39</b>, 139 (2013); P. F. Schmit <i>et al.</i>, <span>Phys. Rev. Lett.</span> <b>117</b>, 205001 (2016); G. A. Shipley <i>et al.</i>, <span>Phys. Plasmas</span> <b>26</b>, 102702 (2019); and P. C. Campbell <i>et al.</i>, <span>Phys. Rev. Lett.</span> <b>125</b>, 035001 (2020)], with an effective coefficient of current induction considerably less than 1. However, even when the load is fully compressed to the axis, the effective coefficient does not approach zero but rather converges to a finite value that solely depends on the aspect ratio of the RCP. This is quite favorable for the suppression of magneto-Rayleigh-Taylor instability in the <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>Z</mi></mrow></math> pinch. As for the pointlike <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>X</mi></mrow></math> pinch, the axial magnetic field does not tend to zero but a finite value, though the effective coefficient tends to zero, and this result may be used to suppress the instability in <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>X</mi></mrow></math> pinch and improve the time stability and spatiotemporal unity of hot spots. In addition, the anode and cathode plates have the potential to enhance the current induced in the load. This paper then analyzes the axial distribution and time behavior of the induced current adopting an approximate analytical method and numerical integration and finds an approximate invariance that can be well characterized by <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>δ</mi><mi>t</mi></mrow></math>, the product of the normalized skin depth and time. Similar values of <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>δ</mi><mi>t</mi></mrow></math> indicate similar axial distribution characteristics. When <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>δ</mi><mi>t</mi></mrow></math> is lower than, at, or higher than the critical region (<math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mr","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"51 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140168253","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":"High-power test results for a cylindrical-shell silicon carbide higher-order-mode damper","authors":"Wencan Xu, Z. A. Conway, E. Daly, J. Guo, K. Hernandez, D. Holmes, R. A. Rimmer, F. Severino, K. Smith, D. Weiss, A. Zaltsman","doi":"10.1103/physrevaccelbeams.27.031601","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.031601","url":null,"abstract":"The next high-current Electron-Ion Collider (EIC) is a new accelerator to be built at Brookhaven National Laboratory in collaboration with Thomas Jefferson National Accelerator Facility. In the EIC Electron Storage Ring (ESR), there will be beam currents of up to 2.5 A, which will excite massive higher-order-mode (HOM) power in the 17 single-cell 591 MHz superconducting radio-frequency (SRF) cavities. Damping the HOM power in the ESR SRF cavities is a challenge. A room temperature cylindrical shell shape silicon carbide (SiC) beamline HOM absorber (BLA) was chosen as the baseline design, due to its broadband and high-power capability, and previous demonstrations at other accelerator facilities, albeit at much lower power. Because the EIC BLA HOM power dissipation is significantly greater than the previous applications, it is imperative to carry out high-power testing to determine the maximum device performance levels achievable for thermal transport, rf breakdown, and mechanical stress, prior to finalizing the design. A SiC HOM absorber with a state-of-the-art geometry size was prototyped to verify the shrink-fit technique, test outgassing rate, and high-power handling capability. This paper presents the HOM damper’s prototyping and test results.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"108 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140149695","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":"Electron-beam-based Compton scattering x-ray source for probing high-energy-density physics","authors":"Hans G. Rinderknecht, G. Bruhaug, V. Muşat, G. Gregori, H. Poole, D. Bishel, D. A. Chin, J. R. Rygg, G. W. Collins","doi":"10.1103/physrevaccelbeams.27.034701","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.034701","url":null,"abstract":"The physics basis for an electron-beam-based Compton scattering x-ray source is investigated for single-shot experiments at the major high-energy-density facilities, such as the Omega Laser Facility, National Ignition Facility, and <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>Z</mi></mrow></math> pulsed power facility. A source of monoenergetic (<math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>δ</mi><mi>ε</mi><mo>/</mo><mi>ε</mi><mo>&lt;</mo><mn>5</mn><mo>%</mo></mrow></math>) 10- to 50-keV x rays can be produced by scattering of a short-pulse optical laser by a 23- to 53-MeV electron beam and collimating the scattered photons. The number and spectrum of scattered photons are calculated as a function of electron packet charge, electron and laser pulse duration, laser intensity, and collision geometry. A source delivering greater than <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msup><mrow><mn>10</mn></mrow><mrow><mn>10</mn></mrow></msup></mrow></math> photons in a 1-mm-radius spot and 100-ps time resolution is plausible with the available electron gun and laser technology. Applications of this source for x-ray diffraction, x-ray imaging, x-ray absorption fine structure, and x-ray absorption spectroscopy in high-energy-density physics experiments are described, demonstrating significant advancements compared to the present state of the art.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"17 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140149601","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":"Pinhole camera for electron beam size diagnostic at storage ring with an ultralow emittance","authors":"Andrei Trebushinin, Gianluca Geloni, Svitozar Serkez, Ruslan Khubbutdinov, Evgeny Saldin","doi":"10.1103/physrevaccelbeams.27.032802","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.032802","url":null,"abstract":"In this work, we propose to use a pinhole camera at high photon energies, specifically 200–300 keV, to measure ultra-small electron beam size by means of bending magnet radiation. We show that there is a sufficient photon flux at the detector position. Our theoretical analysis includes an examination of the applicability of the van Cittert-Zernike theorem for the bending magnet radiation generated by an ultralow emittance electron beam and a detailed analysis of the imaging properties of rectangular pinhole cameras. This led us to practical, universal formulas. We identify the optimal aperture size and resolution of the camera in the given geometry. The theoretical findings are further substantiated by wavefront propagation numerical simulations of partially coherent radiation. This study serves both as a practical guide for optical engineering and an educational resource for explaining the imaging properties of pinhole cameras.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"10 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140071118","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-based commissioning of a novelX-band transverse deflection structure with variable polarization","authors":"P. González Caminalet al.","doi":"10.1103/physrevaccelbeams.27.032801","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.032801","url":null,"abstract":"Longitudinal electron-beam diagnostics play a critical role in the operation and control of x-ray free-electron lasers, which rely on parameters such as the current profile, the longitudinal phase space, or the slice emittance of the particle distribution. On the one hand, the femtosecond-scale electron bunches produced at these facilities impose stringent requirements on the resolution achievable with the diagnostics. On the other, research and development of novel accelerator technologies such as beam-driven plasma-wakefield accelerators (PWFA) demand unprecedented capabilities to resolve the centroid offsets in the full transverse plane along the longitudinal bunch coordinate. We present the beam-based commissioning of an advanced <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>X</mi></math>-band transverse-deflection rf structure (TDS) system with the new feature of providing variable polarization of the deflecting force: the PolariX-TDS. By means of a comprehensive campaign of measurements conducted with the prototype, key parameters of the rf performance of the system are validated and a phase-space characterization of an electron bunch is accomplished with a time resolution of 3.3 fs. Furthermore, an analysis of second-order effects induced on the bunch from its passage through the PolariX-TDS is presented.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"23 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140071252","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":"Theoretical and simulation study of dispersive electron cooling","authors":"He Zhao, Lijun Mao, Meitang Tang, Fu Ma, Xiaodong Yang, Jiancheng Yang","doi":"10.1103/physrevaccelbeams.27.033501","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.033501","url":null,"abstract":"In electron cooling, the transverse cooling rate is usually smaller than the longitudinal rate, especially at high energies. By introducing dispersive cooling, it is possible to redistribute the cooling rate between longitudinal and transverse planes. Theoretically, achieving dispersive electron cooling requires an ion dispersion and a transverse gradient of longitudinal friction force. The latter depends on many factors such as the relative momentum offset, transverse displacement, e-beam density distribution, and space charge effect. Therefore, several methods can be employed to achieve dispersive electron cooling based on these factors. Based on the dc electron beam, these factors and their respective impacts on the cooling rate are discussed and analyzed. For the first time, we propose a new mechanism to achieve dispersive cooling for a uniform electron beam by placing part of the ion beam outside of the electron beam. Based on a linear friction force model, we propose a simple formula to numerically estimate the cooling rate redistribution effect of these methods. The analytical results are in good agreement with Monte Carlo calculation and numerical simulation.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"23 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140071117","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 scale microbunching instability driven by high resistivity nonevaporable getter coating resistive-wall impedance","authors":"Weiwei Li, Tianlong He, Zhenghe Bai","doi":"10.1103/physrevaccelbeams.27.034401","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.034401","url":null,"abstract":"Nonevaporable getter (NEG) coating is widely required in the new generation of light sources and circular <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><msup><mi>e</mi><mo>+</mo></msup><msup><mi>e</mi><mo>−</mo></msup></math> colliders for small vacuum pipes to improve the vacuum level, which, however, also enhances the high-frequency resistive-wall impedance and often generates a resonator-like peak in the terahertz frequency region. In this paper, we will use the parameters of the planned Hefei Advanced Light Facility storage ring to study the impact of NEG-coating resistive-wall impedance on the longitudinal microwave instability via particle tracking simulation. Using different NEG-coating parameters (resistivity and thickness) as examples, we find that the impedance with a narrow and strong peak in the terahertz frequency region can cause terahertz scale microbunching instability, which has a low instability threshold current and contributes to a large energy spread widening above the threshold. In order to obtain a convergent simulation of the beam dynamics, one must properly resolve such a peak. The coating with a lower resistivity has a less sharp peak in its impedance spectrum, and there is a regime that it is helpful to suppress the terahertz scale microbunching instability and in return contributes to a higher instability threshold current.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"30 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140055891","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":"Positron acceleration in plasma wakefields","authors":"Gevy J. Cao, Carl A. Lindstrøm, Erik Adli, Sébastien Corde, Spencer Gessner","doi":"10.1103/physrevaccelbeams.27.034801","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.034801","url":null,"abstract":"Plasma acceleration has emerged as a promising technology for future particle accelerators, particularly linear colliders. Significant progress has been made in recent decades toward high-efficiency and high-quality acceleration of electrons in plasmas. However, this progress does not generalize to the acceleration of positrons, as plasmas are inherently charge asymmetric. Here, we present a comprehensive review of historical and current efforts to accelerate positrons using plasma wakefields. Proposed schemes that aim to increase energy efficiency and beam quality are summarized and quantitatively compared. A dimensionless metric that scales with the luminosity-per-beam power is introduced, indicating that positron-acceleration schemes are currently below the ultimate requirement for colliders. The primary issue is <i>electron motion</i>; the high mobility of plasma electrons compared to plasma ions, which leads to nonuniform accelerating and focusing fields that degrade the beam quality of the positron bunch, particularly for high efficiency acceleration. Finally, we discuss possible mitigation strategies and directions for future research.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"95 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140047906","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":"Microbunch rotation in an x-ray free-electron laser using a first-order achromatic bend","authors":"Rachel A. Margraf, James P. MacArthur, Gabriel Marcus, Heinz-Dieter Nuhn, Alberto Lutman, Aliaksei Halavanau, Zhen Zhang, Zhirong Huang","doi":"10.1103/physrevaccelbeams.27.030702","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.030702","url":null,"abstract":"Electrons in an x-ray free electron laser (XFEL) develop periodic density fluctuations, known as microbunches, which enable the exponential gain of x-ray power in an XFEL. When an electron beam microbunched at a hard x-ray wavelength is kicked, microbunches are often washed out due to the dispersion and <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>R</mi><mn>56</mn></msub></math> of the bend. An achromatic (dispersion-free) bend with a small <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>R</mi><mn>56</mn></msub></math>, however, can preserve microbunches, which rotate to follow the new trajectory of the electron bunch. Rotated microbunches can subsequently interact in a repointed undulator to produce a new beam of off-axis x rays. In this work, we demonstrate hard x-ray multiplexing in the Linac Coherent Light Source hard x-ray undulator line using microbunch rotation through a <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mn>10</mn><mtext> </mtext><mtext> </mtext><mi mathvariant=\"normal\">μ</mi><mi>rad</mi></mrow></math> first-order-achromatic bend created by transversely offsetting quadrupole magnets in the FODO lattice. Quadrupole offsets are determined analytically from beam-matrix theory. We also discuss the application of microbunch rotation to out-coupling a cavity-based XFEL.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"6 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140071123","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":"Experimental characterization of the optical klystron effect to measure the intrinsic energy spread of high-brightness electron beams","authors":"Eduard Prat, Christoph Kittel, Marco Calvi, Paolo Craievich, Philipp Dijkstal, Sven Reiche, Thomas Schietinger, Guanglei Wang","doi":"10.1103/physrevaccelbeams.27.030701","DOIUrl":"https://doi.org/10.1103/physrevaccelbeams.27.030701","url":null,"abstract":"The intrinsic energy spread of electron beams needs to be measured to characterize and optimize high-brightness electron beam sources such as those driving x-ray free-electron lasers (FELs). We demonstrate the use of the optical klystron effect as a precise and high-resolution method to measure the electron beam energy spread. The optical klystron setup consists of undulator modules and magnetic chicanes placed between them. The energy spread is found by measuring the radiation power produced in the undulators as a function of the chicanes’ strengths. High resolution and simplicity are the advantages of this approach, in contrast to the standard method, which measures the longitudinal phase space of the electron beam with a transverse deflector. The demonstration was performed at Athos, the soft x-ray FEL beamline of SwissFEL, for which we measured energy spreads below 1 MeV at a central beam energy of 3.4 GeV. We have verified the consistency of the method for different parameters (radiation wavelengths, undulator polarization configurations, and electron bunch durations) and we have benchmarked it against the standard measurement approach using a transverse deflector. Our results confirm the optical klystron as a valid approach to measure the electron beam energy spread. The method can be especially useful to reconstruct low energy spread values, where the conventional approach may be resolution limited, such as in ultra high-brightness radiofrequency photoinjectors or plasma sources, or when transverse deflectors are not available.","PeriodicalId":54297,"journal":{"name":"Physical Review Accelerators and Beams","volume":"22 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140019607","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}