A new model of the CRAC family, CRAC:EPII (Cosmic Ray Atmospheric Cascade: Electron
Precipitation Induced Ionization) is presented. The model allows one to calculate atmospheric
ionization induced by precipitating electrons. The model is based on pre-computed with highprecision
ionization yield functions, which are obtained using full Monte Carlo simulation of
electron propagation and interaction in the Earth’s atmosphere, explicitly considering all physical
processes involved in ion production. The simulations were performed using GEANT 4 simulation
tool PLANETOCOSMICS with NRLMSISE 00 atmospheric model. A quasi-analytical
approach, which allows one to compute the ionization yields for events with arbitrary incidence is
also presented. It is compared with Monte Carlo simulations and good agreement between Monte
Carlo simulations and quasi-analytical approach is achieved.