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Xu X, Li F, Tsung FS, Miller K, Yakimenko V, Hogan MJ, Joshi C, Mori WB. Generation of ultrahigh-brightness pre-bunched beams from a plasma cathode for X-ray free-electron lasers. Nat Commun 2022; 13:3364. [PMID: 35690617 PMCID: PMC9188572 DOI: 10.1038/s41467-022-30806-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 05/18/2022] [Indexed: 11/23/2022] Open
Abstract
The longitudinal coherence of X-ray free-electron lasers (XFELs) in the self-amplified spontaneous emission regime could be substantially improved if the high brightness electron beam could be pre-bunched on the radiated wavelength-scale. Here, we show that it is indeed possible to realize such current modulated electron beam at angstrom scale by exciting a nonlinear wake across a periodically modulated plasma-density downramp/plasma cathode. The density modulation turns on and off the injection of electrons in the wake while downramp provides a unique longitudinal mapping between the electrons’ initial injection positions and their final trapped positions inside the wake. The combined use of a downramp and periodic modulation of micrometers is shown to be able to produces a train of high peak current (17 kA) electron bunches with a modulation wavelength of 10’s of angstroms - orders of magnitude shorter than the plasma density modulation. The peak brightness of the nano-bunched beam can be O(1021A/m2/rad2) orders of magnitude higher than current XFEL beams. Such prebunched, high brightness electron beams hold the promise for compact and lower cost XEFLs that can produce nanometer radiation with hundreds of GW power in a 10s of centimeter long undulator. Laser-produced plasma can be used for acceleration and tuning of particle beams. Here the authors discuss the generation of a bunched electron beam using simulations and its application to X-ray free-electron laser.
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Affiliation(s)
- Xinlu Xu
- SLAC National Accelerator Laboratory, Menlo Park, CA, USA.
| | - Fei Li
- Department of Electrical Engineering, University of California Los Angeles, Los Angeles, CA, USA
| | - Frank S Tsung
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA, USA
| | - Kyle Miller
- Department of Electrical Engineering, University of California Los Angeles, Los Angeles, CA, USA
| | | | - Mark J Hogan
- SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Chan Joshi
- Department of Electrical Engineering, University of California Los Angeles, Los Angeles, CA, USA
| | - Warren B Mori
- Department of Electrical Engineering, University of California Los Angeles, Los Angeles, CA, USA.,Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA, USA
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2
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Abstract
The Shanghai soft X-ray Free-Electron Laser facility (SXFEL), which is the first X-ray FEL facility in China, is being constructed in two phases: the test facility (SXFEL-TF) and the user facility (SXFEL-UF). The test facility was initiated in 2006 and funded in 2014. The commissioning of the test facility was finished in 2020. The user facility was funded in 2016 to upgrade the accelerator energy and build two undulator lines with five experimental end-stations. The output photon energy of the user facility will cover the whole water window range. This paper presents an overview of the SXFEL facility, including considerations of the upgrade, layout and design, construction status, commissioning progress and future plans.
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Huang N, Deng H, Liu B, Wang D, Zhao Z. Features and futures of X-ray free-electron lasers. ACTA ACUST UNITED AC 2021; 2:100097. [PMID: 34557749 PMCID: PMC8454599 DOI: 10.1016/j.xinn.2021.100097] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 03/14/2021] [Indexed: 11/18/2022]
Abstract
Linear accelerator-based free-electron lasers (FELs) are the leading source of fully coherent X-rays with ultra-high peak powers and ultra-short pulse lengths. Current X-ray FEL facilities have proved their worth as useful tools for diverse scientific applications. In this paper, we present an overview of the features and future prospects of X-ray FELs, including the working principles and properties of X-ray FELs, the operational status of different FEL facilities worldwide, the applications supported by such facilities, and the current developments and outlook for X-ray FEL-based research. X-ray free-electron lasers (XFELs) generate X-ray by electrons flying through a periodic magnetic field. XFELs are the leading X-ray sources with ultra-high brightness and ultra-short duration. XFELs can be launched from either the shot noise of the electron beam or the seed. XFEL-laser collision is proposed to learn the nature of vacuum at SHINE. XFELs are being combined with intense lasers and synchrotron radiation light sources.
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Affiliation(s)
- Nanshun Huang
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Haixiao Deng
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China
- Corresponding author
| | - Bo Liu
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China
| | - Dong Wang
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China
| | - Zhentang Zhao
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China
- Corresponding author
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4
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Extending the Photon Energy Coverage of a Seeded Free-Electron Laser via Reverse Taper Enhanced Harmonic Cascade. PHOTONICS 2021. [DOI: 10.3390/photonics8020044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
External seeded free-electron lasers (FELs) hold promising prospects for producing intense coherent radiation at high harmonics of a conventional laser. The practical harmonic up-conversion efficiencies of current seeding techniques are limited by various three-dimensional effects on the electron beam. In this paper, a novel method is proposed to extend the wavelength coverage of a seeded FEL by combining the reverse taper undulator with the echo-enabled harmonic generation. The proposed technique can significantly enhance the bunching at ultra-high harmonics and preserve the electron beam qualities from degradation by deleterious effects. Theoretical analysis and numerical simulation are performed, and the results demonstrate that stable, intense, nearly fully coherent FEL pulses with photon energy up to 1 keV can be generated. The proposed technique may open up new opportunities to obtain laser-like pulses at sub-nanometer wavelength.
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5
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Hwang JG, Schiwietz G, Abo-Bakr M, Atkinson T, Ries M, Goslawski P, Klemz G, Müller R, Schälicke A, Jankowiak A. Generation of intense and coherent sub-femtosecond X-ray pulses in electron storage rings. Sci Rep 2020; 10:10093. [PMID: 32572105 PMCID: PMC7308344 DOI: 10.1038/s41598-020-67027-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 06/02/2020] [Indexed: 11/17/2022] Open
Abstract
Temporally short X-ray pulses are an indispensable tool for the study of electron transitions close to the Fermi energy and structural changes in molecules undergoing chemical reactions which take place on a time-scale of hundreds of femtoseconds. The time resolution of experiments at 3rd generation light sources which produce intense synchrotron radiation is limited fundamentally by the electron-bunch length in the range of tens of picoseconds. Here we propose a new scheme for the generation of intense and coherent sub-femtoseconds soft X-ray pulses in storage rings by applying the Echo-Enabled Harmonic Generation (EEHG) method. Many issues for obtaining the EEHG structure such as two modulators and a radiator are solved by a paradigm shift in an achromatic storage ring cell. Numerical demonstration of the feasibility of the scheme for the BESSY II beam parameters is presented.
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Affiliation(s)
- J-G Hwang
- Helmholtz-Zentrum Berlin (HZB), Albert-Einstein Straße 15, Berlin, 12489, Germany.
| | - G Schiwietz
- Helmholtz-Zentrum Berlin (HZB), Albert-Einstein Straße 15, Berlin, 12489, Germany
| | - M Abo-Bakr
- Helmholtz-Zentrum Berlin (HZB), Albert-Einstein Straße 15, Berlin, 12489, Germany
| | - T Atkinson
- Helmholtz-Zentrum Berlin (HZB), Albert-Einstein Straße 15, Berlin, 12489, Germany
| | - M Ries
- Helmholtz-Zentrum Berlin (HZB), Albert-Einstein Straße 15, Berlin, 12489, Germany
| | - P Goslawski
- Helmholtz-Zentrum Berlin (HZB), Albert-Einstein Straße 15, Berlin, 12489, Germany
| | - G Klemz
- Helmholtz-Zentrum Berlin (HZB), Albert-Einstein Straße 15, Berlin, 12489, Germany
| | - R Müller
- Helmholtz-Zentrum Berlin (HZB), Albert-Einstein Straße 15, Berlin, 12489, Germany
| | - A Schälicke
- Helmholtz-Zentrum Berlin (HZB), Albert-Einstein Straße 15, Berlin, 12489, Germany
| | - A Jankowiak
- Helmholtz-Zentrum Berlin (HZB), Albert-Einstein Straße 15, Berlin, 12489, Germany
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6
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7
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Zhao Z, Feng C, Chen J, Wang Z. Two-beam based two-stage EEHG-FEL for coherent hard X-ray generation. Sci Bull (Beijing) 2016. [DOI: 10.1007/s11434-016-1060-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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8
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Fu F, Wang R, Zhu P, Zhao L, Jiang T, Lu C, Liu S, Shi L, Yan L, Deng H, Feng C, Gu Q, Huang D, Liu B, Wang D, Wang X, Zhang M, Zhao Z, Stupakov G, Xiang D, Zhang J. Demonstration of nonlinear-energy-spread compensation in relativistic electron bunches with corrugated structures. PHYSICAL REVIEW LETTERS 2015; 114:114801. [PMID: 25839281 DOI: 10.1103/physrevlett.114.114801] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Indexed: 06/04/2023]
Abstract
High quality electron beams with flat distributions in both energy and current are critical for many accelerator-based scientific facilities such as free-electron lasers and MeV ultrafast electron diffraction and microscopes. In this Letter, we report on using corrugated structures to compensate for the beam nonlinear energy chirp imprinted by the curvature of the radio-frequency field, leading to a significant reduction in beam energy spread. By using a pair of corrugated structures with orthogonal orientations, we show that the quadrupole wakefields, which, otherwise, increase beam emittance, can be effectively canceled. This work also extends the applications of corrugated structures to the low beam charge (a few pC) and low beam energy (a few MeV) regime and may have a strong impact in many accelerator-based facilities.
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Affiliation(s)
- Feichao Fu
- Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
- IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Rui Wang
- Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
- IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Pengfei Zhu
- Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
- IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Lingrong Zhao
- Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
- IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Tao Jiang
- Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
- IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Chao Lu
- Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
- IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Shengguang Liu
- Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
- IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Libin Shi
- Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
- IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Lixin Yan
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - Haixiao Deng
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Chao Feng
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Qiang Gu
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Dazhang Huang
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Bo Liu
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Dong Wang
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Xingtao Wang
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Meng Zhang
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Zhentang Zhao
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Gennady Stupakov
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Dao Xiang
- Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
- IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Jie Zhang
- Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
- IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240, China
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9
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Xiang D, Hemsing E, Dunning M, Hast C, Raubenheimer T. Femtosecond visualization of laser-induced optical relativistic electron microbunches. PHYSICAL REVIEW LETTERS 2014; 113:184802. [PMID: 25396374 DOI: 10.1103/physrevlett.113.184802] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Indexed: 06/04/2023]
Abstract
It has long been known that lasers can interact with relativistic electrons in magnetic undulators to imprint sinusoidal modulations that can be used to slice electrons into microbunches equally separated at the laser wavelength. Here we report on the first direct measurement of laser-induced microbunching of a relativistic electron beam with femtosecond resolution in the time domain. Using a modified zero-phasing technique to map the electron beam's temporal structures into the energy space, we show that this method can be used to directly quantify the time and spectral content of coherent current modulations imprinted on the beam for harmonic and multicolor lasing applications in accelerator-based light sources.
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Affiliation(s)
- Dao Xiang
- Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Erik Hemsing
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Michael Dunning
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Carsten Hast
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Tor Raubenheimer
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
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10
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Hemsing E, Dunning M, Hast C, Raubenheimer T, Xiang D. First characterization of coherent optical vortices from harmonic undulator radiation. PHYSICAL REVIEW LETTERS 2014; 113:134803. [PMID: 25302894 DOI: 10.1103/physrevlett.113.134803] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Indexed: 06/04/2023]
Abstract
We describe the experimental generation and measurement of coherent light that carries orbital angular momentum from a relativistic electron beam radiating at the second harmonic of a helical undulator. The measured helical phase of the light is shown to be in agreement with predictions of the sign and magnitude of the phase singularity and is more than 2 orders of magnitude greater than the incoherent signal. Our setup demonstrates that such optical vortices can be produced in modern free-electron lasers in a simple afterburner arrangement for novel two-mode pump-probe experiments.
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Affiliation(s)
- E Hemsing
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - M Dunning
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - C Hast
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - T Raubenheimer
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Dao Xiang
- Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
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11
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Deng H, Feng C. Using off-resonance laser modulation for beam-energy-spread cooling in generation of short-wavelength radiation. PHYSICAL REVIEW LETTERS 2013; 111:084801. [PMID: 24010444 DOI: 10.1103/physrevlett.111.084801] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Indexed: 06/02/2023]
Abstract
To improve temporal coherence in electron beam based light sources, various techniques employ frequency up conversion of external seed sources via electron beam density modulation; however, the energy spread of the beam may hinder the harmonic generation efficiency. In this Letter, a method is described for cooling the electron beam energy spread by off-resonance seed laser modulation, through the use of a transversely dispersed electron beam and a modulator undulator with an appropriate transverse field gradient. With this novel mechanism, it is shown that the frequency up-conversion efficiency can be significantly enhanced. We present theoretical analysis and numerical simulations for seeded soft x-ray free-electron laser and storage ring based coherent harmonic generation in the extreme ultraviolet spectral region.
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Affiliation(s)
- Haixiao Deng
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, People's Republic of China
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12
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Marinelli A, Hemsing E, Dunning M, Xiang D, Weathersby S, O'Shea F, Gadjev I, Hast C, Rosenzweig JB. Generation of coherent broadband photon pulses with a cascaded longitudinal space-charge amplifier. PHYSICAL REVIEW LETTERS 2013; 110:264802. [PMID: 23848882 DOI: 10.1103/physrevlett.110.264802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Indexed: 06/02/2023]
Abstract
The longitudinal space-charge amplifier has been recently proposed by Schneidmiller and Yurkov as an alternative to the free-electron laser instability for the generation of intense broadband radiation pulses [Phys. Rev. ST Accel. Beams 13, 110701 (2010)]. In this Letter, we report on the experimental demonstration of a cascaded longitudinal space-charge amplifier at optical wavelengths. Although seeded by electron beam shot noise, the strong compression of the electron beam along the three amplification stages leads to emission of coherent undulator radiation pulses exhibiting a single spectral spike and a single transverse mode. The on-axis gain is estimated to exceed 4 orders of magnitude with respect to spontaneous emission.
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Affiliation(s)
- A Marinelli
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095, USA.
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13
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Dunning M, Hemsing E, Hast C, Raubenheimer TO, Weathersby S, Xiang D, Fu F. Demonstration of cascaded optical inverse free-electron laser accelerator. PHYSICAL REVIEW LETTERS 2013; 110:244801. [PMID: 25165931 DOI: 10.1103/physrevlett.110.244801] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Indexed: 06/03/2023]
Abstract
We report on a proof-of-principle demonstration of a two-stage cascaded optical inverse free-electron laser (IFEL) accelerator in which an electron beam is accelerated by a strong laser pulse after being packed into optical microbunches by a weaker initial laser pulse. We show experimentally that injection of precisely prepared optical microbunches into an IFEL allows net acceleration or deceleration of the beam, depending on the relative phase of the two laser pulses. The experimental results are in excellent agreement with simulation. The demonstrated technique holds great promise to significantly improve the beam quality of IFELs and may have a strong impact on emerging laser accelerators driven by high-power optical lasers.
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Affiliation(s)
- M Dunning
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - E Hemsing
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - C Hast
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - T O Raubenheimer
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - S Weathersby
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - D Xiang
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - F Fu
- Department of Physics, Shanghai Jiao Tong University, Shanghai 200240, China
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14
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Marinelli A, Dunning M, Weathersby S, Hemsing E, Xiang D, Andonian G, O'Shea F, Miao J, Hast C, Rosenzweig JB. Single-shot coherent diffraction imaging of microbunched relativistic electron beams for free-electron laser applications. PHYSICAL REVIEW LETTERS 2013; 110:094802. [PMID: 23496718 DOI: 10.1103/physrevlett.110.094802] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Indexed: 06/01/2023]
Abstract
With the advent of coherent x rays provided by the x-ray free-electron laser (FEL), strong interest has been kindled in sophisticated diffraction imaging techniques. In this Letter, we exploit such techniques for the diagnosis of the density distribution of the intense electron beams typically utilized in an x-ray FEL itself. We have implemented this method by analyzing the far-field coherent transition radiation emitted by an inverse-FEL microbunched electron beam. This analysis utilizes an oversampling phase retrieval method on the transition radiation angular spectrum to reconstruct the transverse spatial distribution of the electron beam. This application of diffraction imaging represents a significant advance in electron beam physics, having critical applications to the diagnosis of high-brightness beams, as well as the collective microbunching instabilities afflicting these systems.
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Affiliation(s)
- A Marinelli
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095, USA
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15
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Hemsing E, Marinelli A. Echo-enabled x-ray vortex generation. PHYSICAL REVIEW LETTERS 2012; 109:224801. [PMID: 23368128 DOI: 10.1103/physrevlett.109.224801] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Indexed: 06/01/2023]
Abstract
A technique to generate high-brightness electromagnetic vortices with tunable topological charge at extreme ultraviolet and x-ray wavelengths is described. Based on a modified version of echo-enabled harmonic generation for free-electron lasers, the technique uses two lasers and two chicanes to produce high-harmonic microbunching of a relativistic electron beam with a corkscrew distribution that matches the instantaneous helical phase structure of the x-ray vortex. The strongly correlated electron distribution emerges from an efficient three-dimensional recoherence effect in the echo-enabled harmonic generation transport line and can emit fully coherent vortices in a downstream radiator for access to new research in x-ray science.
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Affiliation(s)
- E Hemsing
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
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16
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Dunning M, Hast C, Hemsing E, Jobe K, McCormick D, Nelson J, Raubenheimer TO, Soong K, Szalata Z, Walz D, Weathersby S, Xiang D. Generating periodic terahertz structures in a relativistic electron beam through frequency down-conversion of optical lasers. PHYSICAL REVIEW LETTERS 2012; 109:074801. [PMID: 23006375 DOI: 10.1103/physrevlett.109.074801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2012] [Indexed: 06/01/2023]
Abstract
We report generation of density modulation at terahertz (THz) frequencies in a relativistic electron beam through laser modulation of the beam longitudinal phase space. We show that by modulating the energy distribution of the beam with two lasers, density modulation at the difference frequency of the two lasers can be generated after the beam passes through a chicane. In this experiment, density modulation around 10 THz was generated by down-converting the frequencies of an 800 nm laser and a 1550 nm laser. The central frequency of the density modulation can be tuned by varying the laser wavelengths, beam energy chirp, or momentum compaction of the chicane. This technique can be applied to accelerator-based light sources for generation of coherent THz radiation and marks a significant advance toward tunable narrow band THz sources.
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Affiliation(s)
- M Dunning
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
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