Authors:M. Blaauw, I. Degenaar, C. Yonezawa, H. Matsue, and J. de Goeij
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 (Σs) and absorption cross section (Σa) of the samples were determined by monitoring the neutron flux in four positions just outside the sample container. With
the Σs and Σa 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.