Results of Simulations of High-Power Klystrons

The MASK code is a 2-1/2 dimensional particle-in-cell code which has been applied to the simulation of a number of microwave devices. We discuss implementation of algorithms for the simulation of high-power klystrons. These algorithms use the cavity properties and the MASK results to find selfconsistent solutions in both the linear (small signal) parts of the klystron as well as for the high-power cavities. The method is used to model the existing 35 MW tube and the 50 MW tube being built for the SLC project. Dependence of magnetic field profile and geometry on tube performance is discussed. Effects of radial beam dynamics on efficiency are described. Simulation results are compared to experimental data.