Author: Yan, J.W.
Paper Title Page
TU2A3
 Opportunities and Challenges of the Hard X-ray Self-seeding System at the European XFEL  
 
  • S. Liu, P. Dijkstal, C. Grech, M.W. Guetg, V. Kocharyan, T. Long, N.S. Mirian, W. Qin
    DESY, Hamburg, Germany
  • G. Geloni, N.G. Kujala, C. Lechner, S. Serkez, J.W. Yan
    EuXFEL, Schenefeld, Germany
  
  The Hard X-ray Self-seeding system (HXRSS) at the European XFEL provides users with longitudinally coherent X-ray FEL pulses with narrow bandwidth and high spectral density. With this setup we have achieved a maximum spectral density of about 1 mJ/eV at 9 keV. Combined with the MHz repetition rate, it opens up exciting new opportunities in a wide range of scientific fields. However, the increasing user demand and expectations also poses challenges in machine tuning and operation parameter ranges. We will summarize the HXRSS performance we have achieved and the user delivery experiences in the last two years.  
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TH2A2
 Generation of Intense Attosecond Pulses at the European XFEL  
 
  • J.W. Yan, G. Geloni, C. Lechner, S. Serkez
    EuXFEL, Schenefeld, Germany
  • Y. Chen, P. Dijkstal, M.W. Guetg, E. Schneidmiller
    DESY, Hamburg, Germany
  
  X-ray free-electron lasers (XFELs) have paved the way for significant advancements in attosecond science by generating intense, ultrashort pulses. We are currently developing AttoSecond Pulses with eSASE and Chirp-Taper schemes (ASPECT) project at the European XFEL, designed to exploit these capabilities. In its initial stages, ASPECT will be used to produce attosecond-long pulses at two out of the three SASE lines at the European XFEL: SASE1 and SASE3, dedicated to producing hard and soft x-rays respectively. In this presentation, we will report design studies and preliminary experimental results at the European XFEL.  
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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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