“…In order to verify the background model we simulated background response of Natalya-2M and Fast X-ray Monitor (FXM) (Trofimov et al, 2011) instruments of CORONAS-PHOTON mission and compared these results with the measured data which had been obtained by the instruments during orbital operation in 2009. Simulated and measured deposited energy spectra generally exhibit good agreement in the energy range from 50 keV to 1500 MeV.…”