Procedure for generating high-resolution gamma spectra using Monte Carlo modelling and spectrum post-processing

This study illustrates in detail generating realistic high-resolution gamma spectra by using the Geant4 toolkit and a well-defined spectrum post-processing procedure. The effects addressed by spectrum post-processing were natural background, energy resolution, non-symmetrical peak shapes, and random coincidence summing effects. The validity of the mathematical model of the used HPGe detector was verified by comparing the simulated to the experimental spectra obtained by using a set of certified standard point-like gamma sources. The relative differences between the total number of counts in the simulated and experimental spectra were around 0.5% or less. The average ratio of the difference between the counts in each channel of the simulated and experimental spectra to the combined counting uncertainty in each channel was below 0.3. This result demonstrates that the described procedure can be successfully applied for generating realistic gamma spectra.