Monte Carlo simulation of scintillator efficiency for GSO single crystal II

To efficiently utilize light output of GSO scintillator, we have investigated influence of Compton effect, surface roughness, scintillator size and light transmissivity to the energy spectrum using Monte Carlo simulation when irradiated by a γ-ray of 662 keV from 137Cs. The new founding is that Compton effect does not have any influence to the photoelectric peak of the energy spectrum, but the other factors do. When the scintillator is cubic, 10 x 10 x 10 mm3, and all the surfaces are polished, the photoelectric peak follows Gaussian. When the scintillator takes either rough surface or low light transmissivity, the peak tends to deviate from the Gaussian, having a shoulder in the upper side of the peak, which degrades energy resolution. The deviation gets larger when the scintillator is elongated as 5 x 5 x 30 mm3