INVESTIGATION OF HIGH ABSORBED DOSES IN THE INTERSECTIONS OF THE EUROPEAN XFEL UNDULATOR SYSTEMS

This work presents measurements of the absorbed doses in the vicinity of phase shifter (PS) installed in intersections of the Undulator Systems at the European X-Ray Free Electron Laser (XFEL). In addition, Geant4 Monte Carlo simulations were performed to further investigate the radiation field present in these intersections. Measurements in the downstream undulator cell in SASE3 showed similar doses for the films placed at the PS entrance and near PS motors. Both measurements and simulations indicate that the radiation field near PS motors is not caused by the high-energy electron interactions with the beam pipe close to the PS. The measurements of the absorbed doses at the PS entrance in the upstream undulator cells are also presented.