Monte Carlo Simulated the Detection Efficiency of Different H/R Ratio of NaI:Ti Crystal

We make use of Monte Carlo simulation to investigate the detection efficiency versus different H/R ratio of NaI:Tl detectors, and the volume of detector is constant. The energy of incident monoenergetic γ rays is 4.438 MeV, 1.331 MeV and 0.662 MeV emitted from AmO2Be, 137Cs and 60Co respectively. The size of NaI:Tl detector dimension is setted up to 20 groups of different radius (H) and height (R), whereas the volume of NaI:Tl crystal will not be changed. The result reveals that the detector efficiency dependence on H/R ratio of the NaI:Tl detector and the incident γ-photon energy. For very low H/R ratio, the detector efficiency increase rapidly and tend to be stable. We draw a conclusion that when the H/R ratio is approximately equal to 1.5, the incubation effect is more obvious, which contribute to the increase of detection efficiency. It is meaningful of the research, namely, it be beneficial to design the optimal dimension of detector for detecting γ rays of 4.438 MeV, 1.331 MeV and 0.662 MeV.