Based on platform of three-dimensional particle-in-cell (PIC), CHIPIC, modules of particle swarm optimization (PSO) and genetic algorithm (GA) are designed to optimize a relativistic backward wave oscillator (RBWO), respectively. Comparisons of PSO and GA are implemented in three kinds of parameters of RBWO:Continuous parameter, discrete parameter, and mix parameters. It shows that performances of PSO are better than that of GA. PSO has higher optimization accuracy and convergence rate than GA.

Collisions between electrons in an ion source are analyzed theoretically.Processing models for null collisions between electron and other particles and Coulomb collisions among electrons are analyzed.With different storage and call mechanism,two Monte Carlo collision(MCC) processing models are developed.Then,MCC numerical models are added to a particle simulation software CHIPIC.With ion source JAERI 10A,the models ale verified.