Theoretical investigation of absolute neutron detection

Abstract

A survey was made of the detection systems classified as 'flat response' in order to establish their use in high accuracy measurements of absolute neutron intensities for a wide range of neutron sources. Two detection systems involving neutron moderation in either graphite of an hydrogenous material were selected as having the most suitable characteristics. Numerical solutions of the neutron transport equations for these systems were computed to determine the conditions required to produce minimum variation of efficiency with energy. It was shown that, with the suitable choice of moderator composition and size, it should be possible to reduce these errors to less than one per cent over the energy range 100 eV to 4 MeV.