Primary study of foilless diode used in 0.34THz source

A high beam quality foilless diode for high power 0.34THz surface-wave oscillator (SWO) source is presented in this paper. In order to research the influence of the guiding magnetic field and the structural parameters on the performance of foilless diode, the method of 2.5 dimensional particle-in-cell (PIC) codes UNIPIC is introduced. The simulation results suggest that the guiding magnetic field should be higher than 2.5 tesla and the distance between the beam and anode-wall had better to be set as 0.22~0.40mm considering the cyclotron radius of electron. The radius of anode has an important impact on the diode and it is chose as 5~8 mm in 0.34THz source. The adjustment of the distance between cathode and anode is also available to affect the diode. Finally, the optimized diode is studied and the diode can provide a high quality beam with the current of 2.3kA and electron energy of 380keV, which satisfies the demand of 0.34THz source well.