Measurement of the Angular Neutron Energy Spectra Originating from a 14-MeV Neutron Source in Liquid Air

An experiment to measure the detailed energy, angular, and spatial distribution of neutrons originating from a 14-MeV neutron source in liquid air is presented. The neutron spectra are measured with a proton-recoil NE213 scintillator combined with a collimator. The measurements cover the energy range from 2 to 18 MeV at eight different angles from 0 to 90 deg. The distance between the neutron source and the measurement position varies from 60 cm (52 g/cm²) to 150 cm (130 g/cm²) in liquid air. The results are discussed and compared with known theoretical neutron transport calculations.