Assessment of radioactivity in some soil samples of qatar by gamma-ray spectroscopy and the derived dose rates

The activity concentrations of some natural and artificial radionuclides have been measured in soil samples by gamma-ray spectroscopy using a high purity germanium detector. From the obtained gamma-ray spectra, the activity concentrations of ²³⁸U and ²³²Th natural decay series and the long-lived naturally occurring radionuclide ⁴⁰K have been determined, in addition to the fission product ¹³⁷Cs. A wide range of different gamma-ray lines ranging from -100 keV up to 2.6 MeV, associated with the decay products of²³⁸U and²³²Th series have been analyzed independently to obtain more statistically significant overall results. The data have been analyzed, when secular equilibrium of the radionuclides is achieved within the samples. The weighted activity concentrations of ²³⁸U and²³²Th series vary from 4.4 to 64.4 and 0.8 to 7.6 Bq/kg, respectively. The activity concentrations of ⁴⁰K and ¹³⁷Cs have been found in the range of13.6 to 179.5 and 0.3 to 3.7 Bq/kg, respectively. Based on the measured activity concentrations, dose rate, radium equivalent, radiation hazard index and annual effective dose rates have been estimated. The values obtained are within the recommended safety limits.