ELECTRON BEAM PROFILE MONITORING SYSTEM FOR BEIJING FREE ELECTRON LASER EXPERIMENTS

The electron beam profile monitoring system located between exit of the 30 MeV linac a d exit of the undulator on Beijing free electron laser (BFEL) is described. The system consists of four sets of fluorescent screen probes controlled remotely by a pneumatic actuator, an optical magnifying system, a TV-camera monitoring station, and a TV signal digitizing system. According to the result of simulation experiment, the spatial resolution of the system is approximately 0.lmm that meets the overall requirement of BFEL. The profile, position and distortion of the electron beam and alignment of the laser beam along the undulator can be tested and measured with this system.