Absolute determination of 14 MeV neutron spectrum by means of liquid-scintillation spectrometer and threshold foil-detectors

Abstract The absolute fast neutron spectrum generated by a 14 MeV neutron generator was determined by means of a liquid scintillation recoil-proton spectrometer together with threshold foil-detectors. The liquid scintillation spectrometer provides the relative neutron energy spectrum. Knowing this relative spectrum, one threshold detector alone is enough to convert the relative spectrum into an absolute spectrum. In practice, more than one threshold detector is used to confirm the result. The method of obtaining the absolute spectrum is described and it is estimated to have an uncertainty of about ±8%