A Study on Monte Carlo simulation of the radiation environment above GeV at the DAMPE orbit

The Dark Matter Particle Explorer (DAMPE) has been undergoing a stable on-orbit operation for more than 6 years and acquired observation of over 11 billion events. And a better understanding of the overall radiation environment on the DAMPE orbit is crucial for both simulation data production and flight data analysis. In this work, we study the radiation environment at the low Earth orbit and develop a simulation software package using the framework of ATMNC3, in which state-of-the-art full 3D models of the Earth's atmospheric and magnetic-field configurations is integrated. We consider in our Monte Carlo procedure event-by-event propagation of the cosmic rays in the geomagnetic field and their interaction with the Earth's atmosphere, focusing on the particles above GeV that are able to trigger the DAMPE data acquisition system. We compare the simulation results with the cosmic-ray electrons and positrons (CREs) flux measurements made by DAMPE. The overall agreement on both the spectral and angular distribution of the CREs flux demonstrates that our simulation is well established. Our software package could be of more general usage for the simulation of the radiation environment at the low Earth orbit of various altitudes.