Simplified Efficiency Calibration Methods for Semiconductor Detectors used in Criticality Dosimetry

Abstract

``Oversimplified'' and ``simplified'' methods based on true coincidence summing effect used in uncomplicated determination of the photo-peak efficiency of the semiconductor High Purity Germanium (HPGe) detector system are suggested and verified. The methods and calibrated $^{60}$Co radioactive source may be used to commission any HPGe detector to use during potential criticality event. The determined accuracy of the semiconductor HPGe detector system using this method is a few percent (for the detector system used in this study it was $\simeq$8\% for oversimplified and $\simeq$5\% for simplified methods accordingly) reasonable, expected, and good enough to use for estimation of neutron dose from irradiated human blood in a potential criticality event. Moreover, if one can experimentally deduce the photo-peak efficiency for $^{60}$Co 1333 keV $\gamma$-ray line using the suggested methods, then with a few percent accuracy this efficiency could be also used for 1369 keV $\gamma$-ray line in the decay of $^{24}$Na isotope.