The key technology development of high power CW electron linac; Beam dynamics of injector for high power CW electron

Nomura, Masahiro  ; Yamazaki, Yoshio ; Toyama, Shinichi  ; Emoto, Takashi

It is important for a high power electron linac to design the injector, because the space charge effect is large. The injector consists of a 200 kV DC gun, two magnetic lens, a RF chopper, a chopper slit, a prebuncher, a buncher and an accelerating tube 1. In order to design the injector, beam trajectories are simulated by PARMELA which is modified by PNC. In this report, three simulation results are shown. The first result is the beam trajectory from the gun to the exit of the solenoid coils. There is a thick concrete wall between the gun to the RF chopper. Low energy electrons are transported through the long solenoid coils. It can be seen from the first result that two magnetic lens between the gun and the solenoid coils can reduce the emittance growth. The second result is for the chopper part. The novel chopper system is designed to reduce the emittance growth. The last result is the beam trajectory from gun to chopper slit. From those simulation results, it can be seen that the emittance at the end of the injector is reduced to about 10 mm mrad by the novel chopper system.