Development and Benchmark Studies of the Indiana Rf Photocathode Source Simulator

The Indiana Rf Photocathode Source Simulator (IRPSS) code is being developed to calculate the electromagnetic fields created by an electron beam in a photoinjector, and to simulate the effects of these fields on the beam using time-dependent Green's function methods. In this poster, we show initial IRPSS simulation results for a simplified photoinjector geometry consisting of a semi-infinite cylindrical pipe and cathode using the experimental parameters for the BNL 1.6 GHz photocathode gun [1]. We also show the excellent agreement within a benchmark study between the IRPSS code operating with the same simplified geometry and the analytical solution for a disk-like bunch and its image bunch propagating with uniform velocities in opposite directions with free space boundary conditions. Our benchmark study has demonstrated that the effects of self-fields reflecting from the pipe, as well as the electromagnetic shock fronts due to causality conditions, may be significant in understanding the physics of photoinjectors. [1] K. Batchelor et al, Development of a High Brightness Electron Gun for the Accelerator Test Facility at Brookhaven National Laboratory, EPAC88, Rome, June 1988.