Optimization of gun parameters for a pulsed power electron gun

Extensive simulation work has been done to identify the optimal parameters for a pulsed power electron gun. PBGUNS, an electrostatic beam optics code, was used to optimize the electrode shape and the beam spatial distribution, including modeling the focusing effect of a curved cathode surface. MAFIA, a particle-in-a-cell code, was used to investigate those aspects that required time dependence, such as longitudinal energy spread. The range of agreement between the two codes was also investigated. The transverse phase space at a comparison plane was found to be very close (within 1% at low currents and 4% for higher currents), even for bunch lengths shorter than the gap transit time.