Accelerator beam dynamics at the European X-ray Free Electron Laser

Abstract

We consider the collective beam dynamics in the accelerator of the European X-ray Free Electron Laser for electron bunches with charges of 250 and 500 pC. The dynamics has been studied numerically with different computer programs, and we struggle to include properly the whole beam physics with collective effects. Several scenarios of the longitudinal dynamics are considered for the peak currents of 5 and 10 kA. A procedure for the choice of the machine parameters is described, and the tolerances of radio frequency parameters of accelerating modules along the accelerator are calculated. The bunch properties at the end of the accelerator before the undulator line are analyzed. A comparison between measurements and simulations for the beam energy loss due to wakefields is presented.