Post-linac beam collimation study of SHINE

Purpose X-ray free-electron laser facilities require high-repetition and high-energy electron beams,which makes the radiation safety become an important issue due to beam loss.Beam collimation is used to protect the undulator and other devices by removing the beam halo in operation,as well as absorbing the off-axis beam in the case of machine failure.Method In this paper,the beam collimation system in the switchyard of the SHINE is presented.Results and conclusion Tracking with an expanded initial beam distribution,the efficiency of the collimation system is shown,and the detailed collimation performance is simulated to evaluate the available limitation from the acceptance of the undulator.Moreover,the accidental beam loss and wakefield effects are also considered to ensure the reliability of the collimation.