MONTE CARLO SIMULATION OF PEAK EFFICIENCY CURVES OF THE SUPERPURE HPGE DETECTOR IN ENVIRONMENTAL GAMMA SPECTROMETRY USING MCNP4C2 CODE

Abstract

In this paper, the Los Alamos Laboratory's MCNP4C2 code (2) was used to determine the peak effieciency curves of the HPGe detector of Nuclear Physics Department, University of Natural Sciences of Ho Chi Minh City. We also investigated the changes of the efficiency curves with the distances from sources to detector. The standard sources used for the experiments of test are Cs-137 (661,7 key), Na-22 (1274.5 key), và Co-60 (1173.3 key và 1332.5 keV) which were borrowed from Nuclear Research Instutitute (NRI), Dalat. The standard sources used for more simulating are Am-241 (59.5 keV), Co-57 (122.1 keV), Se-75 (96.7 keV), Ba-133 (81.0 keV; 356.0 keV), Eu-152 (1408.0 keV). They have the same geometry with NRI's. The ratios of the experimetal efficiencies to simulation efficiencies are higher than 0.9. It shows that our simulation program based on MCNP4C2 code is good enough for later studies on our HPGe spectrometer.