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

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

Artificial and Natural Radioactivity Measurements and Radiation Dose Assessment in the Vicinity of Ghana Nuclear Research Reactor-1 (GHARR-1)

Radioactivity concentrations of <sup>226</sup>Ra, <sup>232</sup>Th, <sup>40</sup>K and <sup>137</sup>Cs in soil samples and water sources around the Ghana Research Reactor-1 (GHARR-1) and the immediate surroundings have been measured using gamma spectrometry. The primary aim of the study was to establish baseline radioactivity levels in the environs of GHARR-1. The average activity concentration of <sup>226</sup>Ra, <sup>232</sup>Th, <sup>40</sup>K and <sup>137</sup>Cs were 22.3 ± 1.12 Bq kg<sup>-1</sup>, 49.8 ± 1.60Bq kg-1, 99.60 ± 5.81 Bq kg<sup>-1</sup> and 1.48 ± 0.25 Bq kg<sup>-1</sup> for soil and 0.60 ± 0.11 Bq l<sup>-1</sup>, 2.13 ± 0.21 Bq l<sup>-1</sup>, 10.75 ± 0.84 Bq l<sup>-1</sup> and 0.47 ± 0.05 Bq l<sup>-1</sup>for the water, respectively. The <sup>226</sup>Ra and <sup>232</sup>Th concentrations compare quite well with world averages, whilst the <sup>40</sup>K concentration was lower than the world average. The levels of <sup>137</sup>Cs observed in the samples are within the range of ‘background’  concentrations. The estimated average annual effective doses from external exposure to soil and ingestion of water samples were calculated to be 0.06 mSv and 0.53 mSv, respectively. The estimated outdoor  external gamma dose rate measured in air ranged from 20-430 nGy h<sup>-1</sup> with an average value of 100 nGy h<sup>-1</sup>, which is higher than the world average value of 59 nGy h<sup>-1</sup>. In the case of water samples, the average value was higher than the guidance level of 0.1 mSv y<sup>-1</sup>, as recommended by the European Union and the World Health Organization