Simulation studies of the eROSITA particle-induced background using a highly detailed mass model

A new eROSITA mass model is presented for particle background simulations as well as ray-tracing simulations using the Geant4 toolkit. The origin of the aluminum and iron fluorescence lines seen in the eROSITA spectrum was investigated using Monte Carlo simulations of the particle background for the filter wheel closed position with the new mass model. The geometry offers an unprecedented level of detail, especially close to the CCD. The mass model is written in the Geometry Description Markup Language (GDML) and consists mainly of Geant4 Constructed Solid Geometry (CSG) volumes, which allows for fast simulation runtimes.