Temperature effects on MIPs in the BGO calorimeters of DAMPE**This work was supported by National Key Program for Research and Development (No. 2016YFA0400200) and by NSFC (11303105, 11673021). The DAMPE mission was funded by the strategic priority science and technology projects in space science of the Chinese Academy of Sciences (No. XDA04040000 and No. XDA04040400)

Abstract

In this paper, we present a study of temperature effects on BGO calorimeters using proton MIPs collected in the first year of operation of DAMPE. By directly comparing MIP calibration constants used by the DAMPE data production pipe line, we find an experimental relation between the temperature and signal amplitudes of each BGO bar: a general deviation of −1.162%/°C, and −0.47%/°C to −1.60%/°C statistically for each detector element. During 2016, DAMPE’s temperature changed by ∼8°C due to solar elevation angle, and the corresponding energy scale bias is about 9%. By frequent MIP calibration operation, this kind of bias is eliminated to an acceptable value.