Geant4 based Monte Carlo simulation for verifying the modified sum-peak method

The modified sum-peak method can practically estimate radioactivity by using solely the peak and the sum peak count rate. In order to efficiently verify the method in various experimental conditions, a Geant4 based Monte Carlo simulation for a high-purity germanium detector system was applied. The energy spectra in the detector were simulated for a 60Co point source in various source to detector distances. The calculated radioactivity shows good agreement with the number of decays in the simulation.