Due to the widespread use of granites as building and ornamental materials, measurements of natural radioactivity for a total 27 selected samples of commercial granites used in Egypt were carried out by using a high pure germanium detector. The activity concentrations of 226Ra, 232Th and 40K of commercial granites ranged from 25 to 356, 5 to 161, and 100 to 1,796 (Bq kg−1), respectively. The concentrations of these radionuclides are compared with the international recommended values. To evaluate the radiological hazard of the natural radioactivity, the radium equivalent activity, the absorbed dose rate, the effective dose rate, and the hazard index have been calculated. The radium equivalent activity Raeq varied from 41 to 669 (Bq kg−1) which exceeds the permitted value (370 Bq kg−1) and the internal hazard index H in varied from 0.2 to 2.8 which is higher than 1. The absorbed dose rate due to the natural radioactivity in the samples under investigation ranged from 19 to 310 (nGy h−1). The total effective dose rates per person indoors were determined to be 0.09 to 1.5 (mSv year−1).
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机译：由于花岗岩广泛用作建筑和装饰材料，因此使用高纯锗探测器对埃及使用的总共27个选定的商业花岗岩样品进行了自然放射性测量。商业花岗岩的 226 Ra， 232 Th和 40 K的活性浓度范围为25至356、5至161和100至1,796 （Bq kg -1 ）。将这些放射性核素的浓度与国际推荐值进行比较。为了评估自然放射性的放射性危害，已计算出了镭当量活性，吸收剂量率，有效剂量率和危害指数。镭当量活度Ra eq 从41变为669（Bq kg -1 ），超过允许值（370Bq kg -1 ）内部危害指数H in 在0.2到2.8之间变化，高于1。由于被研究样品的自然放射性，吸收剂量率在19到310之间（nGy h -1 ）。确定每人在室内的总有效剂量率为0.09至1.5（mSv年 -1 ）。
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