Computer Graphics to Separate Neutron from Gamma-Ray Spectra, Applied to the Measurement of Neutron Attenuation Coefficients Using an NE-213 Scintillator

A new approach is described in the use of NE-213 detectors to perform neutron spectra measurements, which have been developed jointly by the U.S. Naval Academy and the Naval Surface Weapons Center. The approach is based on collecting a three-dimensional matrix of neutron and gamma-ray data. The dimensional plots of the collected data, which are computer generated, are used to ensure proper separation of the neutrons from gamma rays. After separation, the spectra are calibrated, binned, renormalized, and finally unfolded. In this manner neutron energy spectra and kerma are obtained. Linear attenuation coefficients for 14-MeV neutrons were determined by placing iron, lead, aluminum, polyester, and polyethylene-based materials between the neutron source and the NE-213 detector.