TAILIEUCHUNG - Intrinsic Efficiency Calibration for Uranium Isotopic Analysis in Soil Samples
In this work, we present the results of using the non-destructive gamma spectroscopic method for uranium isotopic analysis and checking the status of radioactive equilibrium between 238U and 226Ra in soil samples. In order to analyze uranium isotopes and check the status of equilibrium between 238U and 226Ra the activity ratios 235U/238U and 238U/226Ra were measured. | VNU Journal of Science: Mathematics – Physics, Vol. 33, No. 1 (2017) 48-52 Intrinsic Efficiency Calibration for Uranium Isotopic Analysis in Soil Samples Bui Van Loat1,*, Somsavath Leuangtakoun1,2, Cao Dang Luu1, Bui Thi Hong1, Khong Nam Khang1, Nguyen The Nghia1, Nguyen Hong Ha1, Vu Thi Kim Duyen3 1 Department of Nuclear Physics, Faculty of Physics, VNU University of Science, 334 Nguyen Trai, Hanoi, Vietnam 2 National University of Laos, : 7322, Dongdok, Vientiane, Laos 3 Centre for Env. Trea. Tech. Minisry of Defence, 282 Lac Long Quan, Hanoi, Vietnam Received 12 January 2017 Revised 28 February 2017; Accepted 20 March 2017 Abstract: In this work, we present the results of using the non-destructive gamma spectroscopic method for uranium isotopic analysis and checking the status of radioactive equilibrium between 238 U and 226Ra in soil samples. In order to analyze uranium isotopes and check the status of equilibrium between 238U and 226Ra the activity ratios 235U/238U and 238U/226Ra were measured. The these activity ratios were determined based on the characteristic gamma rays and using intrinsic (relative) detection efficiency calibration method. The results obtained shows that this suggested analytical method can be used to determine the uranium concentration in the case of the samples having arbitrary shapes and it does not require the use of any reference materials. Keywords: Secular equilibrium, gamma-spectrometry, intrinsic efficiency calibration, MGA method. 1. Introduction The activity ratio 235U/238U and status of equilibrium between 238U and 226Ra is one of the important parameters for analyses of geological and soil samples [1, 2]. When 238U and 226Ra in secular equilibrium, the activity ratio 238U/226Ra is equal to one. However, the 238U is sometime radioactive disequilibrium with 226Ra, then the activity ratio 238U/226Ra will be different from one. As it is difficult to interpret disequilibrium by simply comparing radiometric and chemical
đang nạp các trang xem trước
