Space Environment Background Calculation for HXMT

The Hard X-ray Modulation Telescope (HXMT) is a broad band X-ray (1~250 keV) astronomical satellite. Its core payload, High Energy X-ray Telescope (hereafter HE), operates in the hard X-ray (20~250 keV) range. HXMT/HE will perform an all-sky hard X-ray survey and focused observations with the highest sensitivity. To achieve a high sensitivity, it is important to reduce the background that caused by the interactions between the satellite and the space particles. With reference of documents and up-to-date observation data which describe the background of near earth space, a suit of self-consistent data and formulas related to background particle of near earth space are sorted out. The background of HXMT and its variation with time and orbit are also given through simulation calculation with software Geant 4.