The Soft X-ray Solar polarimeter-spectrometer (SOLPEX) experiment is planned to be placed in Roscosmos’ Multipurpose Laboratory Module “NAUKA” on International Space Station (ISS) in 2019. The experiment is design to detect polarization and X-ray spectra of solar flares. Due to very high, few percent, linear polarization detection limit, accurate background estimation and modeling is crucial.
Calculating the background photoelectric effect, Compton scattering and Bremsstrahlung were taken into account. Luminescence background from particles produced in solar flares was simulated using Geant4. Additionally, theoretical spectra was modeled in order to simulate full SOLPEX detector response for M5 and X1 solar flare classes.