Directional Neutron Spectrometer

A detector capable of measuring the energy and direction of 1 - 15-MeV neutrons is decided. The instrument consists of two conventional neutron detectors (organic scintillators and phototubes) and electronics which, for events in which a neutron is scattered by the first scintillator into the second, measures the energy of the recoil proton in the first scintillator and the time of flight of the scattered neutron between the two detectors. These two quantities determine the energy of the incident neutron and its direction relative to the line joining the two detectors. The response to a point source of 2.5-MeV neutrons is shown.