BEXCO - Room A(101/102)
[CRD051] Measurement of absolute energy scale of ECAL of DAMPE with geomagnetic rigidity cutoff
DAMPE is a space-borne cosmic ray telescope satellite designed to measure electron, gamma and cosmic ray nuclei with high energy resolution and wide dynamic range, which was launched in December 2015, into a sun-synchronous orbit at 500km altitude and 97 degree inclination. BGO calorimeter of DAMPE is a total absorbed calorimeter for measuring energy of cosmic ray via separately detecting shower development in each crystal. The determination of the absolute energy scale of BGO calorimeter is very crucial for estimating systematic uncertainty on energy measurement. In this paper, a method was developed to measure absolute energy scale of DAMPE via geomagnetic cutoff on cosmic ray electron and positron spectrum. The rigidity cutoff on cosmic ray electron and positron was calculated firstly by using IGRF-12 model and cosmic ray particle trajectory tracing code developed by Smart and Shea. Then the measurement of cosmic ray electron and positron spectra were also performed in several MacIiwain-L bins based on over 400 days’ flight data of DAMPE. By directly comparing calculated geomagnetic cutoffs with DAMPE measured results, the estimation values on absolute energy scales of DAMPE were presented at ~10GeV energy range with total uncertainty within energy resolution.