Utilization of different radionuclides for high-energy extended efficiency calibration of a HPGe for improved determination of calcium and sulfur using k 0 -INAA

The present study reports on the performance of three reactor-produced radionuclides ( 24 Na, 56 Mn, and 72 Ga) and one accelerator-produced radionuclide ( 56 Co) for extending the full-energy peak efficiency calibration of a coaxial HPGe detector up 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 24 Na 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.