Neutron spectrometer with position-sensitive proportional counters

A spherical neutron counter for spectrometry and dosimetry has been developed. The counter consists of a spherical polyethylene moderator and three slender 3He position-sensitive proportional counters inserted into the moderator. The thermal neutron distribution in the moderator, which is a function of the energy of the incident neutrons is obtained with the proportional counters. Characteristics of the counter have been studied with experiments and Monte Carlo simulations. Also shown are energy spectra of a 252Cf neutron source that are obtained by an unfolding method using the thermal neutron distributions as response functions.