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摘要
The analysis of naturally occurring radionuclides (Ra-226, Th-232 and K-40) has been carried out in 40 soil samples collected from four districts of the Northern Rajasthan, India using gamma-ray spectrometry with an NaI(Tl) detector. The activity concentrations of the samples range from 38 +/- 9 to 65 +/- 11 Bq kg(-1) with a mean value of 52 Bq kg(-1) for Ra-226, from 8 +/- 8 to 32 +/- 9 Bq kg(-1) with a mean value of 19 Bq kg(-1) for Th-232 and from 929 +/- 185 to 1894 +/- 249 Bq kg(-1) with a mean value of 1627 Bq kg(-1) for K-40. The measured activity concentration of Ra-226 and K-40 in soil was higher and for Th-232 was lower than the worldwide range. Radium equivalent activities were calculated for the soil samples to assess the radiation hazards arising due to the use of these soils in the construction of buildings. The calculated average radium equivalent activity was 205 +/- 20 Bq kg(-1), which is less than the recommended limit of 370 Bq kg(-1) by the Organization for Economic Cooperation and Development. The total absorbed dose rate calculated from the activity concentration of Ra-226, Th-232 and K-40 ranges from 77 to 123 nGy h(-1) with an average value of 103 nGy h(-1). The mean external (H-ex) and internal hazard indices (H-in) for the area under study were determined to be 0.55 and 0.69, respectively. The corresponding average annual effective dose was found to be 0.63 mSv.
- 出版日期2014-1
