Comparison of k0–NAA measurement results with calculated uncertainties for reference samples

Standard samples of well-defined geometry containing accurately known amounts of Co, Fe, Gd, Mo, Nd, Sb, Se, W, Zn and Zr were prepared and assayed using k0–based neutron activation analysis (k0–NAA). Measurement results for six independent determinations of each standard spiked sample were evaluated and compared to calculated uncertainties using the computer program ERON, which computes uncertainty propagation factors from the relevant formulae and calculates the overall uncertainty following the internationally recommended approach. The calculated relative expanded uncertainties U (k=2), which ranged from 6 to 11% for particular nuclides/gamma-lines agreed well with the measurements results thus proving the correctness of the applied approach. One of the important measures to further reduce uncertainties in the k0–NAA measurements is to review and re-determine more accurately specific nuclear constants involved in the relevant calculations.