k0-NAA quality assessment in an Algerian laboratory by analysis of SMELS and four IAEA reference materials using Es-Salam research reactor

Different types of synthetic multi-element standard material (SMELS) and four IAEA reference materials, 140, Sl-1, Soil-7 and Lichen-336 were analyzed for validation and QC/QA of the k0-standardised Neutron Activation Analysis (k0-NAA). The samples of SMELS and RMs were irradiated at Es-Salam research reactor and measured on an absolutely calibrated HPGe detector with 35% relative efficiency connected to a Canberra Genie 2k inspector. Concentrations of 33 elements such as As, Au, Ba, Br, Ca, Ce, Co, Cr, Cs, Eu, Fe, Hf, In, K, La, Mn, Mo, Na, Nd, Rb, Sb, Sc, Se, Sm, Sr, Ta, Tb, Th, Tm, U, Yb, Zn, and Zr were determined in SMELS and RMs. The analytical results agreed well with the assigned values of SMELS and certified values of RMs. In the case of RMs, concentrations of a few elements, whose certified values are not available, could be determined. The comparison between experimental values and assigned/certified data for SMELS and RMs was made by means of the results from Relative Bias, Z-score and U-score. The relatives bias of the elements determined in SMELS with respect to the assigned values were all within±4.6%. For RMs with respect to certified values were within±10% except for few elements for which RB varied from −28.6% to +12.8%. The Z-score values at 95% confidence level for most of the elements in both the materials were within ±1. The U-scores for most of the elements were lower than 1.