Comparison of different approaches to estimate uncertainty budget in k_0-INAA measurement

摘要

Three CRMs of different matrix composition were analysed, representing an environmental matrix sample (BCR-320R Channel Sediment), a botanical matrix sample (SRM 1547 Peach Leaves) and a zoological matrix sample (SRM 1566b Oyster Tissue). The element mass fractions were obtained using the KayWin program. Analytical measurement uncertainty was determined by two approaches: (1) the routine procedure applying combination of the overall uncertainty u(m) = 3.5 % and statistical uncertainty of the peak area determination and (2) the procedure applying the dedicated ERON program for calculating uncertainty. Performance of altogether 31 certified values was tested by means of calculating E_n numbers. For the remaining 52 non-certified values, comparison between uncertainties obtained by the two approaches was made. When using the first approach, the E_n number showed satisfactory performance in 28 cases; by using the second approach, the E_n number showed satisfactory performance in 27 cases. None of the unsatisfactory performances (E_n > 1) appeared to be of systematic nature. The uncertainties obtained by applying the two approaches revealed a big extent of consistency. As the present nuclear database lacks lot of data that serve as input to the ERON program, in particular uncertainties of Q_0 factors, estimates need to be introduced for the missing values, emphasising the urgent need to upgrade the database with missing data.