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  • Author or Editor: T. Bučar x
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Summary  

Special aspects of the uncertainty quantification in k 0-NAA are discussed and applied in accordance with the Guide to the Expression of Uncertainty in Measurement (GUM), on a model case. The uncertainty budget is calculated highlighting the contribution and the importance of the different parameters to be taken into account. The importance of the nuclide-specific and neutron fluence-specific approach in estimating individual uncertainty contributions is emphasized and demonstrated by examples of Au, Cr, Rb, and Sb determinations.

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Abstract  

Cellulose cylinders and circular filter papers spiked with known amounts of standard element solutions were prepared for studying some aspects of assessing measurement uncertainty of NAA and the elemental distribution measured by micro-PIXE analysis. Results for the cylinders showed strongly non-homogeneous distribution of the elements, both in radial and vertical directions, dominantly caused by osmosis driven transport of added liquid solution from the centre to the edges. Results for the thin cellulose filter paper disks exhibited weaker peaking of the standard element concentrations at the edges in comparison with the thick cylinders.

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Abstract  

A suite of natural matrix reference materials (RMs) were used to assess the quality of analytical results obtained by k 0-instrumental neutron activation analysis (k 0-INAA) at the Joef Stefan Institute (IJS). Five certified reference materials (CRMs) from the Institute for Reference Materials and Measurements (IRMM), two standard reference materials (SRMs) from the National Institute of Standards and Technology (NIST), three RMs from the International Atomic Energy Agency (IAEA) and one RM from IJS were analyzed. Altogether, results for twenty-four elements in inorganic matrices and twenty-nine elements in organic matrices, obtained by k 0-INAA, were compared to certified values. Results obtained show good agreement with certified or assigned values except for Fe, La, Nd, Sm and U in inorganic matrices, and Ag, Al and Cr in organic matrices.

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