Design and simulation of beam position monitor for 200 MeV linac in HLS

In order to improve injection efficiency of HLS (Hefei Light Source), an appropriate BPM (beam position monitor) is needed to provide the transverse positions and longitudinal phases of linac and transfer line beam. The original stripline BPM for HLS Linac, which is 20.8 degrees in azimuthal angle and has a poor performance in coupling signals on electrodes, is redesigned and calculated through Mafia and CST Microwave Studio. The new stripline BPM structure, which is 60 degrees and 183.8 mm long, has a better performance in time response, spectrum, linearity and sensitivity when a beam passes by. Lastly, the position resolution and time resolution of the new structure is theoretically calculated, which meets the requirement of HLS Linac and transfer line.