TH4A —  Working Group A: Linac-based Light Sources   (31-Aug-23   16:30—18:00)
Chair: M.W. Guetg, DESY, Hamburg, Germany
Paper Title Page
TH4A1
 Progress Towards X-ray Free-electron Laser Driven by Plasma Wakefield Accelerator at SXFEL  
 
  • F. Li, J.F. Hua, W. Lu, Z. Song, H.Y. Xiao
    TUB, Beijing, People’s Republic of China
  • C. Feng, Z. Wang, Z.T. Zhao
    SARI-CAS, Pudong, Shanghai, People’s Republic of China
  • T.L. Zhang
    Tsinghua University, Beijing, People’s Republic of China
  
  Free-electron lasers (FEL) are unique light source for various applications in structural biology, chemistry and condense physics. Plasma-based accelerators can provide ultrahigh accelerating gradient which is 3~4 orders of magnitude higher than conventional technology, holding the potential for a revolution in particle accelerators. This novel technology therefore has been given high expectations for the development of compact free-electron lasers. SXFEL is a single-pass FEL user facility that provides 2~10 nm radiation for fundamental and applied research. In frame of this report, we present concept and design of a large-bandwidth XFEL based on a plasma wakefield accelerator (PWFA) driven by SXFEL electron beams. An ultrabroad bandwidth is achieved by chirping the electron beam in a hollow-channel plasma and simulations demonstrate that a spectral bandwidth of up to 24% can be obtained in this scheme. We will also present the recent progress on the construction of PWFA-based XFEL experimental station at SXFEL, and the preliminary experimental results on the PWFA and FEL radiation generation.  
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TH4A2 A Compact Inverse Compton Scattering Source Based on X-band Technology and Cavity-enhanced High Average Power Ultrafast Lasers 257
 
  • A. Latina, R. Corsini, L.A. Dyks, E. Granados, A. Grudiev, V. Mușat, S. Stapnes, P. Wang, W. Wuensch
    CERN, Meyrin, Switzerland
  • E. Cormier
    CELIA, Talence, France
  • G. Santarelli
    ILE, Palaiseau Cedex, France
  
  A high-pulse-current photoinjector followed by a short high-gradient X-band linac and a Fabry-Pérot enhancement cavity are considered as a driver for a compact Inverse Compton Scattering (ICS) source. Using a high-power ultra-short pulse laser operating in burst mode in a Fabry-Pérot enhancement cavity, we show that outcoming photons with a total flux over 1013 and energies in the MeV range are achievable. The resulting high-intensity and high-energy photons allow various applications, including cancer therapy, tomography, and nuclear material detection. A preliminary conceptual design of such a compact ICS source and simulations of the expected performance are presented.  
slides icon Slides TH4A2 [2.962 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-FLS2023-TH4A2  
About • Received ※ 22 August 2023 — Revised ※ 26 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023
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TH4A3
 An Active Q-switched X-ray Regenerative Amplifier Free-electron Lasers  
 
  • J. Tang, E. Hemsing, Z. Huang, Z. Zhang
    SLAC, Menlo Park, California, USA
  
  Despite tremendous progress in X-ray free-electron laser (FEL) science over the last decade, future applications still demand fully coherent, stable X-rays that have not been demonstrated in existing X-ray FEL facilities. In this Letter, we describe an active Q-switched X-ray regenerative amplifier FEL (XRAFEL) to produce fully coherent, high-brightness, hard X-rays. By using simple electron beam phase space manipulation, we show this scheme is very flexible in controlling the X-ray cavity quality factor Q and hence the output radiation. We report both theoretical and numerical studies on this scheme with a wide range of accelerator, X-ray cavity, and undulator parameters  
slides icon Slides TH4A3 [1.855 MB]  
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TH4A4 A Proposal for Generating Fully Coherent X-ray FEL with Femtosecond Pulse Based on Fresh-Slice 261
 
  • Z.F. Gao
    SSRF, Shanghai, People’s Republic of China
  • J.W. Yan
    EuXFEL, Schenefeld, Germany
  
  This study aims to propose a new principle for generating fully coherent femtosecond X-ray pulse on the Shanghai soft X-ray Free Electron Laser User Facility (SXFEL-UF), which was based on fresh-slice technique. The electron beam was kicked transversely to get a time-related transverse tilt. The sub-10-femtosecond bunch was achieved first because of the spatiotemporal synchronization effect of the seed laser modulation. Then the FEL pulse duration was even shorter because of harmonic lasing. In the cascaded HGHG mode, the laser generated by the beam tail modulated the beam head in the second stage to reach higher harmonics, while in the EEHG mode, the same part of the electron beam was modulated twice. The influence of emittance and energy chirp of the electron beam on the scheme was analyzed, and the instability caused by transverse position jitter and energy jitter of the chirped beam was evaluated. The relationship between the pulse duration and the transverse deflection of the beam is verified. The scheme is also explored to generate linearly polarized femtosecond pulse at 6 nm and circularly polarized femtosecond pulse at 3 nm simultaneously.  
slides icon Slides TH4A4 [3.281 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-FLS2023-TH4A4  
About • Received ※ 21 August 2023 — Revised ※ 24 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023
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