Gamma Radiation Measurements in Tunisian Marbles

The radioactivity of 15 kinds of different granites collected in Tunisia was determined by gamma-ray spectrometry using hyper-pure germanium (HPGe) detector. The average activity concentrations for primordial radionuclides 238U, 232Th and 40K were respectively 33.24, 8.01 and 116.98 Bq/kg. The activity concentrations ranged from 3.59 to 87.37 Bq/kg for 238U, from 0.45 to 25.34 Bq/kg for 232Th and from 24.06 to 380.23 Bq/kg for 40K. The measured activity concentrations were used to assess of the radium equivalent activity ranged from 22.2 to 995.8 Bq/kg, the absorbed dose rate in air from 7 to 1209 nGy/h and the internal (0.1 to 2.8) and external (0.1 to 2.7) hazard indices. The data obtained in this study may be useful for natural radioactivity mapping.