Validation experiment for large-sample prompt-gamma neutron activation analysis

Abstract

A method is proposed for the implementation of large-sample prompt-gamma neutron activation analysis (LS-PGNAA). The method was tested with four different sample materials at the thermal PGNAA facility at JAERI, Japan. The macroscopic scattering cross section (∑ s) and absorption cross section (∑ a) of the samples were determined by monitoring the neutron flux in four positions just outside the sample container. With the ∑ s and ∑ a determined, the spatial neutron density distribution [n(r)] inside the sample material was derived. Taking n(r) and the gamma-ray self-absorption into account simultaneously, the effective geometric gamma-ray detection efficiency for large samples as a function of gamma-ray energy was calculated. Taking silicon as test element, the concentrations found agreed to within 7% with the known concentrations in the four sample materials examined, both when using relative standardization and with absolute standardization. © 2007 Akadémiai Kiadó.