Simplified efficiency calibration methods for semiconductor detectors used in criticality dosimetry

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 Co-60 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 similar or equal to 8% for oversimplified and similar or equal to 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 Co-60 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 Na-24 isotope.

Automated summary

Simplified methods for determining the photo-peak efficiency of semiconductor HPGe detector system are proposed and verified. These methods can be used to estimate neutron dose from irradiated human blood in potential criticality events.