Readout Electronics of DAMPE BGO Calorimeter and the Status during the First 18 Months in Orbit

The DAMPE (DArk Matter Particle Explorer) is a scientific satellite which was successfully launched in Dec., 2015, with the major scientific objective of indirect searching for the clue of dark matter particles in space. The BGO (Bismuth Germanate Oxide) calorimeter is a critical sub-detector of DAMPE payload, with the functions of measuring the energy of cosmic particles, distinguishing positrons/electrons and gamma rays from hadron background, and providing trigger information. It is composed of 308 BGO crystal bars and each bar is coupled by two Hamamatsu R5610A PMTs (photomultiplier tubes), from both sides respectively. Each PMT sends out three dynode signals, to achieve a large dynamic range, which results in 1848 signal channels. A readout electronics system, which consists of 16 FEE (Front End Electronics) modules, is designed to precisely measure the charges of PMT signals and to provide “hit” signals. The in orbit status of the electronics system is to be introduced in this paper.