Assessment of measurement result uncertainty in determination of Pb-210 with the focus on matrix composition effect in gamma-ray spectrometry

摘要

Reference materials were used to assess Measurement result uncertainty in determination of Pb-210 by gamma-ray spectrometry, liquid scintillation counting, or indirectly by alpha-particle spectrometry, using its daughter Po-210 in radioactive equilibrium. Combined standard uncertainties of Pb-210 massic activities obtained by liquid scintillation counting are in the range 2-12%, depending on matrices and massic activity values. They are in the range 1-3% for the measurement of its daughter Po-210 using alpha particle spectrometry. Three approaches (direct computation of counting efficiency and efficiency transfer approaches based on the computation and, respectively, experimental determination of the efficiency transfer factors) were applied for the evaluation of Pb-210 using gamma-ray spectrometry. Combined standard uncertainties of gamma-ray spectrometry results were found in the range 2-17%. The effect of matrix composition on self-attenuation was investigated and a detailed assessment of uncertainty components was performed. (C) 2015 Elsevier Ltd. All rights reserved.