5. Calibration and Performance Testing of Sodium Iodide, NaI (Tl), Detector at the Food and Environmental Laboratory of the Radiation Protection Institute of the Ghana Atomic Energy Commission

Abstract

The performance testing of a newly acquired sodium iodide detector (NaI), (Tl)) at Ghana Atomic Energy Commission (GAEC) was investigated by carrying out energy and efficiency calibration on the detector, as well as validation of its calibration. The energy and efficiency calibrations were performed using mixed radionuclides 241 109 57 137 60 standard containing Am, Cd, Co, Cs and Co in the energy range of 60–1333 keV. The energy and efficiency calibration curves obtained compare well with what is available in the literature. Results of the validation of the calibration showed that there were no significance differences between the measured and the calculated activities of the standard radionuclides with activity ratios in the range of 0.90-0.98 and the corresponding percentage deviation in a range of 1.43–10.47%. The average MDA of 238U, 232Th, 40K and 137Cs from background counting rates were estimated to be 0.099 ± 0.055 Bq, 0.061 ± 0.037 Bq, 0.727 ± 0.300 Bq and 0.014 ± 0.006 Bq, respectively.