Validation and calibration of efficiency of various standard source for radioactivity analysis of gamma soil samples

Abstract

Gamma Spectroscopy is one of the instruments used in measuring the radioactivity of environmental components. However, an efficiency value from the gamma spectroscopy detector is needed in order to obtain an accurate measurement. Efficiency calibration of the detector can be determined from the calibration curve of the standard source used. The calibration curve of a standard source can be affected by the matrix. The study aims to examine the two of the adjacency matrixes from various standard source for radioactivity analysis of gamma soil samples. The efficiency calibration of standard matrix sand (EG-ML) and ore (IAEA-RGU-1) are y = 3.1761x−0,838 and y = 4.3459x−0,913 respectively. The qualitative measurement of the radioactivity analysis was not influenced by differences in the two standard sources used, where the analyzed soil samples contained K-40, Bi-212, Pb-212, Bi-214, Pb-214, Ra-226, and Ac-228 which were natural radionuclides. However, the quantitative results of radioactivity values show differences with a percentage of 1.1% to 26.2% respectively. The validation of the method carried out on each EG-ML and IAEA RGU-1 standard source obtained satisfactory results with a bias value of ⩽ 2% is 1.2% and 4.3%, the precision value of ⩽ 8% is 0.6% and 1.4%, and the value of Z ⩽ 2 is 0.32 and 0.03 respectively.