Abstract
The present study reports on the performance of three reactor-produced radionuclides (Na-24, Mn-56, and Ga-72) and one accelerator-produced radionuclide (Co-56) for extending the full-energy peak efficiency calibration of a coaxial HPGe detector up to similar to 3100 keV at different detector to source distances. The differences between the efficiency curves obtained with and without the use of high-energy gamma emitters radionuclides have a considerable impact on the accuracy of the Na, Ca, and S determination by the k(0)-INAA as evidenced by analysis results of reference materials. The results revealed that Na-24 is the most suitable radionuclide for high-energy efficiency calibration due to its reasonable availability, low production cost, simple decay scheme, and well-defined decay properties.