Neutron activation analysis of large volume samples: The influence of inhomogeneity

A large sample neutron activation analysis (LSNAA) facility is under development at GRR-1 research reactor, NCSR ‘Demokritos’, to perform multi-element, non-destructive, contamination-free analysis of large volume samples. Correction algorithms have been derived to account for thermal neutron and gamma-ray self-attenuation in macroscopically homogeneous samples, as well as the photon detection efficiency to voluminous samples, based on no prior knowledge of the sample matrix composition. In the present study Monte Carlo simulations were performed to estimate the influence of inhomogeneities of major (matrix) and trace element on the accuracy of the technique. Types of inhomogeneities that can lead to severe errors in the analysis were depicted. The potential of including inhomogeneity tests in the measuring procedure to ensure the method’s applicability was examined.