Tsing Hua Univ, Dept Engn Phys, Beijing 100084, Peoples R China
; Tsing Hua Univ, Ctr Astrophys, Beijing 100084, Peoples R China
; CAS, Inst High Energy Phys, Beijing 100049, Peoples R China
The performance of the Hard X-ray Modulation Telescope (HXMT) is significantly influenced by the collecting area. Based on the simulations of the background and the point spread function of the instrument, we propose a new collimator scheme in which the weight of the whole detectors can be decreased about 80kg. This is equal to the weight of 5 or more new detectors. We hope this new scheme will help to increase the number of detectors under the total loading mass limit, so that the collecting area will be larger and the performance of HXMT will be better.