Improvement of sensitivity for foodstuff elemental analysis through thermal and/or EPI-thermal neutron activation analysis

Abstract

Instrumental neutron activation analysis (INAA) for essential and toxic elements in foodstuffs commonly consumed by South Africans as routinely applied at NECSA could not give adequate sensitivity for a variety of elements as shown by previous research. Improvement in sensitivity can be achieved by considering the following aspects: Evaluation of the dominant radionuclide in the irradiated foodstuffs - (extracted from the available data from the previous study). Determination of the cadmium ratio (Red) through irradiation of element standards in the full neutron spectrum as well as irradiation in the cadmium shielded part of the neutron spectrum. Determination of the advantage factors of elements of interest over dominant nuclides in the gamma-spectra of irradiated foodstuffs Determination of the neutron flux and neutron spectrum stability for INAA in the irradiation channels used for instrumental neutron activation analysis at the South African Fundamental Atomic Reactor Installation 1 (SAFARl-1) to evaluate the possible influence on the advantage factors. Research deduced that dominant radionuclide vary according to irradiation-delay-count (IDC) systems, both RINGAS and PRS data indicated that there is change in flux and spectral shift within specified limits and change outside specified limits could be due to various activities carried out at SAFARl-1 Advantage factors have been determined thus irradiation facility can be chosen to obtain optimal sensitivity for elements of interest in specific food matrices.