Fig. 1. Characteristics of HPGe detector as provided by the manufacturer.
Fig. 2. CT radiogram of the detector system.
Fig. 3. The simulation spectrum of the 133Ba source. The distance between the source and end-cap is 10 mm, and the dead layer thickness is assumed to be 1.0 mm.
Fig. 4. Peak efficiency curves for several values of the thickness of the dead layer.
Fig. 5. Determination of the thickness of the dead layery the source point of 5 mm. The black points are from the simulation providing the ratio of the number of events on the 81 keV photoelectron peak to that in the 356 keV photoelectron peak. The horizontal band is from the experimental data. The vertical band determines the dead layer thickness by comparing the experimental ratio and simulation fitting line. The error bars for the simulation points are smaller than the data point size and invisible in the plot.
Fig. 6. An experimental spectrum of the 133Ba source. The distance between the source and end-cap is 5 mm, and the dead layer thickness is assumed to be 1.0 mm
Fig. 7. Mapping of fraction of gamma ray absorbed at different layers in the detector.
Table 1. Detector dimensions as specified by the manufacturer and as optimised by Monte Carlo simulations.
Table 2. Gamma ray intensities of a 133Ba ,152Eu source
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