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. •Monte Carlo simulation, Geant4, was applied to simulating the sum-peak method via a HP-Ge detector.•A 60Co point source was the used to the simulation.•The simulation was validated in peak-shape and relative efficiency of the HP-Ge detector.•Both the conventional sum-peak method and the modified sum-peak method was validated.•The modified sum-peak method was confirmed as a practical technique in the simulation.