Study on the repeatability and reproducibility of low-level radioactivity measurements using the analysis of variance tool

The repeatability and reproducibility need to be investigated to evaluate the stability of low-level radioactivity measurements with respect to an analysis method, as well as their dependence on measuring parameters. In this study, the procedures for gross alpha/beta and gamma-ray activity measurements were investigated in the Department of Radiation and Environment Safety at the Center for Nuclear Technologies (CNT). Moreover, an interlaboratory comparison was organized with other institutions, i.e. Dalat Nuclear Research Institute (DNRI), Institute for Nuclear Science and Technology (INST), and Institute of Public Health in HCM (IPH-HCM). To evaluate the repeatability and reproducibility of measures undertaken by the low-level radioactivity measurements, the certified reference materials (CRM), i.e. IAEA-CRM-385 (Natural and artificial radionuclides in sediment from the Irish Sea), NIST-SRM-4322c (Americium-241 Radioactivity Standard), and IAEA-CRM-RGK-1, together with 6 collected real samples were analyzed for 238U, 232Th, 226Ra, 228Ra, 210Pb and 40K. The analysis of variance (ANOVA) tool with  respect to the average, standard deviation, F, p-value, and F-crit parameters was applied for the evaluation. The obtained results in the study revealed that the repeatability and reproducibility were stable for the low-level radioactivity measurements at the CNT which meets the laboratory’s quality management requirements.