Author: Hedqvist, A.
Paper Title Page
TUPAB101 Monte Carlo Simulations and Neutron and Gamma Fluence Measurements to Investigate Stray Radiation in the European XFEL Undulator System 1615
 
  • O.E. Falowska-Pietrzak, A. Hedqvist, F. Hellberg
    Stockholm University, Stockholm, Sweden
  • N. Bassler
    DCPT, Aarhus N, Denmark
  • A. Leuschner, D. Nölle
    DESY, Hamburg, Germany
  • F. Wolff-Fabris
    EuXFEL, Schenefeld, Germany
 
  The European X-ray Free Electron Laser (XFEL) is an user facility research centre generating extremely bright and ultra-short SASE x-ray pulses. The laser flashes are generated when electrons of GeV energies pass the undulator systems. Even if the dominating contribution of the radiation field in the undulator is from spontaneous undulator radiation, also electron losses can be observed, e.g. during beam steering or due to beam halo, not captured by the upstream collimation system. The interactions of those particles with the vacuum vessel wall result in the emission of stray radiation. The LB 6419 detector allows to measure both the neutron and the gamma component in the pulsed radiation fields nearby the undulators*. Usually, the real-time measurements show the dominance of the gamma signals. However, in case of particle loss occurs, a neutron signal is observed. In addition, Monte Carlo (MC) simulations conducted using the Geant4 code indicate that neutrons are also present within the undulator’s magnets volume. In this work, we present the LB 6419 measurement data and compare these to our MC simulations, to characterize the radiation field nearby the undulator segment.
* KLETT, A., LEUSCHNER, A., TESCH, N., A dose meter for pulsed neutron fields, Radiat Meas 45 (2010) 1242-1244
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB101  
About • paper received ※ 19 May 2021       paper accepted ※ 02 June 2021       issue date ※ 18 August 2021  
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