Abstract
The optimization of measurement of environmental samples is achieved by putting the sample closer to the detector to increase the full-energy peak efficiency, which leads to decrease of the detection limit. The present work inspects the utilization of Geant4 simulation for a NaI cubic scintillation detector with a cavity using two tracks. The radionuclide option includes coincidence summing, and the monoenergetic option is summing free coincidence. The ratio between the monoenergetic to redionuclide options gives the coincidence summing correction factors. In the experiments a gamma-ray aqueous source containing the radionuclide Eu-152 covering the range from 121 to 1408 keV was used. Comparing the monoenergetic option for calculating the full-energy peak efficiency and the corrected experimental efficiency, the values are in agreement.