Background simulations of WXT aboard the Einstein Probe Mission

The Einstein Probe mission that will be launched in 2022, is dedicated to time-domain high-energy astrophysics. Its primary goals are to discover high-energy transients and to monitor variable objects in 0.5-4 keV energy band. To realize these objectives, EP is equipped with a Wide-filed X-ray Telescope (WXT) which applies the micro-pore optics (MPO). Background is critical for a space X-ray instrument, since it is related to sensitivity and observation data quality. In this work, we study the background components of WXT induced by cosmic X rays, soft X rays from the Galaxy based on ray tracing program. We also investigate the background due to energetic cosmic rays, the count rate of which varies with the thickness of detector sensitive layer. Furthermore, we simulate the contribution of low-energy electrons to the background of WXT, which would degrade the sensitivity notably without electron diverters. The electron diverters for WXT are under development based on simulations.