Study of natural radioactivity and the state of radioactive disequilibrium in U-series for rock samples, North Eastern Desert, Egypt

Twenty rock samples collected from North Eastern Desert in Egypt have been investigated. Natural radionuclide contents have been measured by γ-ray spectrometry employing a shielded HPGe detector. The activities of 238U, 232Th and 40K have been determined in Bq/kg dry weight. The absorbed dose rate of γ radiation ranged from 100.48 to 22,140.53 nGy/h. The representative external hazard index values (Hex) for the corresponding samples were estimated. In the present work, the state of radioactive disequilibrium in the U-series at Wadi Baligh area was studied. The activity ratios between 226Ra/214Pb and 214Pb/214Bi were measured. The thorium-to-uranium concentration ratios (Clark value) were also estimated.