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 yr and acquired observations of over 11 billion events. A better understanding of the overall radiation environment of the DAMPE orbit is crucial for both simulation data production and flight data analysis. In this work, we study the radiation environment at 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 are integrated. We consider in our Monte Carlo procedure event-by-event propagation of 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 electron and positron (CRE) flux measurements made by DAMPE. The overall agreement on both the spectral and angular distribution of the CRE flux demonstrates that our simulation is well established. Our software package could be of more general usage for simulation of the radiation environment of low Earth orbit at various altitudes.