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 which are difficult to homogenize. The method for correction of neutron and gamma-ray self-attenuation assumes that the sample may be considered as homogeneous at the scale of several kilograms. Still, local inhomogeneities may occur with attenuation properties strongly different from the major portion of the sample. The effects of such local inhomogeneities on the accuracy of large sample INAA has been studied by computer simulations. The results indicate that inhomogeneities affecting the gamma-ray attenuation have larger effects than inhomogeneities affecting neutron attenuation. Moreover, inhomogeneities of (trace) elements to be determined have the largest effects.