INFLUENCE OF BEAM TUBE OBSTACLES ON THE EMITTANCE OF THE PITZ PHOTOINJECTOR

For detailed analysis of space charge dominated beams inside an RF Photoinjector PIC-Codes like CST MAFIA TS2/3 can be used. While the interaction of particles with the surrounding geometries are taken into account, the applicability of such codes is restricted due to simulation time and memory consumption as well as by numerical noise. Therefore, only smaller sections of the whole injector can be calculated. On the other hand codes like ASTRA can be used to simulate the whole injector but no interaction between bunch and geometry is included. To make use of the individual advantages of each code described above an interface for bidirectional bunch exchange between the two programs has been implemented. This approach allows for applying the right simulation method depending on the physical effects under investigation. To demonstrate the importance of such an approach the results of detailed numerical studies of the impact of beam tube obstacles like the laser mirror on the achievable emittance of the PITZ RF Photoinjector further downstream will be presented. PITZ is the photo injector test facility at DESY Zeuthen [1].