Wake field computations for the PITZ photoinjector

The computation of wake fields excited by ultrashort electrons bunches in accelerator components with geometrical discontinuities is a challenging problem, as an accurate resolution for both the small bunch and the large model geometry are needed. Several computational codes (PBCI,ROCOCO,CST PARTICLE STUDIOtrade) have been developed to deal with this type of problems. Wake field simulations of the RF electron gun of the Photoinjector Test Facility at DESY Zeuthen (PITZ) are performed with different specialized codes. Here we present a comparison of the wake potentials calculated numerically obtained from the different codes. Several structures of the photoinjector are considered.