Monte Carlo calculation of accurate response functions for a NaI(T1) detector for gamma rays

The accurate response of a cylindrical NAI(T1) detector for gamma rays up to 6.13 MeV has been calculated using a Monte Carlo method. The effects of the detector housing and scintillation efficiency of a NaI(T1) crystal have been investigated. With consideration of these effects, the calculated results of energy spectra, intrinsic total efficiencies and photopeak efficiencies indicate excellent agreement with our experimental data. The variation of spectra, when the position of a gamma source is shifted, has also been studied comparing them with the experimental ones. (orig.)