Abstract

In this paper, the Los Alamos Laboratory’s MCNP4C2 code was used to simulate the Co-60 gamma ray spectra of the HPGe detector and compare to the respectively empirical one, to investigate the X-rays absorption from lead by the 1.5mm copper and 1mm tin liners covering the lead shield, the influence of lead shield on the scattering continuum of the low energy, the change of the spectra shape when placing the source at a near and far distance from the detector. The results of comparing the empirical spectrum with simulated one showed that there was a agreement in the range of energy higher than 250 keV, but in the range of energy lower than 250 keV the empirical spectrum is 12.7% higher than the simulated one. The presence of lead shield and source - supports does almost not influence on counting number in the full energy peak. The results are the foundation to get high accuracy for latter estimating the gamma spectra in environmental sample quantitative analysis.