High-energy neutron spectrum measurements using electrochemically etched CR-39 detectors with radiators and degraders

Abstract

Abstract Spectrometry of fast neutrons based on the measurement of ECE spot density in an electrochemically etched CR-39 detector placed in conjunction with varying thicknesses of polyethylene radiator and a lead degrader, has successfully been demonstrated for mono energetic neutrons up to 19 MeV. No attempt has, however, so far been made to measure the broad neutron energy spectra by using this technique. In this paper we describe the application of this technique for the measurement of the energy spectrum of a cyclotron-produced high-energy (up to 60 MeV) neutron beam. Procedures to apply the technique to spectrum measurements, including spectrum unfolding etc. have been developed and are reported. The computer program NSPEC, previously written to predict ECE responses at various degrader and radiator thicknesses for neutron energies up to 19 MeV, has been modified (and renamed as HENSPEC). The results of measurements have been found in reasonable agreement with the relevant published spectral data.