Application of instrumental neutron activation analysis for determining As, Br, K, La, Mn, Na and Sm in samples of pine wood

Multi-elementary and considered non destructive, the neutron activation analysis is a technique that allows simultaneous and instrumental determination of several elements, becoming especially useful when it is fundamental the knowledge of the total chemical composition, as in the certification of reference materials, application in geochemistry, analyses of aerosols, determination of origin of materials, forensic analyzes and of environmental pollution. However, the dependence of reactors, or other neutrons sources, the generation of radioactive material and the time waiting needed for some determinations are the main barriers pointed int he application of that technique. The present work aimed at establishing the best conditions for the detection of elements of short half-life Br, K, La, Mn, Na and Sm in samples of wood of Pinus, because the reactor used is located distant of the laboratory where the measures of the induced radioactivity are made, to determine trace elements that possess half-lives smaller than two days. For such, suitable equations, using the Surface of Response technique in the SAS software, to minimize the uncertainties of detection of the photopeak function of the elementary concentration and as a decay time.(author)