COMPUTER-SIMULATIONS OF THE EFFECTS OF INHOMOGENEITIES ON THE ACCURACY OF LARGE-SAMPLE INAA

One of the niches for large sample INAA is the analysis of materials w hich are difficult to homogenize. The method for correction of neutron and gamma-ray self-attenuation assumes that the sample may be conside red as homogeneous at the scale of several kilograms. Still, local inh omogeneities may occur with attenuation properties strongly different from the major portion of the sample. The effects of such local inhomo geneities on the accuracy of large sample INAA has been studied by com puter simulations. The results indicate that inhomogeneities affecting the gamma-ray attenuation have larger effects than inhomogeneities af fecting neutron attenuation. Moreover, inhomogeneities of (trace) elem ents to be determined have the largest effects. (C) 1998 Elsevier Scie nce Ltd. All rights reserved.