COMPENSATION OF INITIAL BEAM LOADING FOR ELECTRON LINACS

Serious initial beam loading effect may generate beam loss in the electron linac of the VSX light source (1). Because of the large energy spread, it is difficult to compensate the beam loading with ordinary methods, such as the adjustment of injection timing and ECS (Energy Compensation System). We have developed a phase-amplitude (∆φ -A) modulation system using two fast phase shifters, which is put before a klystron and operated at low power level. In this paper, we report the performance of the test system.