Investigation of cosmic-ray induced background of Germanium gamma spectrometer using GEANT4 simulation

In this article, a GEANT4 Monte Carlo simulation toolkit was used to study the response of the cosmic-ray induced background on a High-Purity Germanium (HPGe) gamma spectrometer in the wide energy range, up to 100 MeV. The natural radiation background measurements of the spectrometer were carried out in the energy region from 0.04 to 50 MeV. The simulated cosmic-ray induced background of the Ge detector was evaluated in comparison with the measured data. The contribution of various cosmic-ray components including muons, neutrons, protons, electrons, positrons and photons was investigated. We also analyzed secondary particle showers induced by the muonic component. - Highlights: • Contribution of various components of cosmic rays on an HPGe gamma spectrometer were studied by Geant4. • The simulated total spectrum shows good agreement with the measurement background spectrum from 3 MeV up to 50 MeV. • Muonic component dominates with 86% of background. • Muons secondary particle shower contributes mostly to the spectrum in the energy region of below 3 MeV.