Detector response function of a HPGe detector to photon energies between 200 keV and 1.5 MeV for Gamma-ray nondestructive assay instrument

A semi-empirical detector response function (DRF) model of HPGe detector was proposed to fit gamma-ray nondestructive assay transmission spectra. The model for each single peak contained a step function, a Gaussian function, and an exponential tail function. The Gaussian standard deviation obtained by electronic noise and Fano factor, so our DRF only had 4 parameters and they were obtained by the weighted nonlinear least-squares fitting method. In the application,
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Eu spectra were obtained by using the 30%, 50%, 70% HPGe detector, and fitted by the established DRF model. Reduced chi-square values were at the interval of 0.039-0.202. Its validity that the model had good versatility, can be applicable to different detection efficiency of HPGe detectors.