Author: Li, C.
Paper Title Page
WEPAB379 Photocathode Laser Development for Superconducting X-Ray Free Electron Lasers at DESY 3599
 
  • C. Li, O. Akcaalan, U. Grosse-Wortmann, I. Hartl, C. Mohr, M. Seidel, H. Tuennermann, C. Vidoli, L. Winkelmann
    DESY, Hamburg, Germany
  • M. Frede, O. Puncken
    neoLASE GmbH, Hanover, Germany
 
  Funding: Deutsches Elektronen-Synchrotron, Hamburg, 22609, Germany
Mod­ern X-Ray Free-Elec­tron Lasers (XFEL) are a key tool to en­able a va­ri­ety of sci­en­tific re­search. Those large-scale ma­chines rely on ro­bust and re­li­able deep ul­tra­vi­o­let (DUV) laser sources to drive elec­trons from their RF pho­to­cath­ode gun. In this paper we pre­sent a new pho­to­cath­ode laser pro­to­type, which of­fers more flex­i­bil­ity in du­ra­tion and shape of the 257.5 nm pulses for dri­ving the CsTe Pho­to­cath­odes of DESY’s su­per­con­duct­ing burst-mode FELs. The laser matches the FEL pulse struc­ture, which are 800 µs bursts at up to 4.5 MHz in­tra­burst-rate with 10 Hz burst-rep­e­ti­tion-rate. In a first ver­sion the sys­tem will offer vari­able DUV pulse du­ra­tions, tun­able from 1 ps to 20 ps to ad­dress dif­fer­ent op­er­a­tional regimes of the XFEL. The laser sys­tem com­prises a high-res­o­lu­tion spec­tral shaper with the op­tion of gen­er­at­ing flat-top DUV pulses for re­duc­ing elec­tron-beam emit­tance at a later ver­sion. The laser is con­structed in a hy­brid Yb:fiber and Yb:YAG ar­chi­tec­ture. Our pro­to­type de­liv­ers 180 uJ pulse en­ergy at 1030 nm and 1 MHz in­tra-burst rate and we demon­strated con­ver­sion of 50µJ of the NIR beam to DUV, re­sult­ing 11.5µJ at 21ps (FWHM) and 6.15 µJ at 1.05 ps (FWHM) pulse du­ra­tion.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB379  
About • paper received ※ 27 May 2021       paper accepted ※ 02 July 2021       issue date ※ 23 August 2021  
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