Ein detektorsystem für ns-flugzeitexperimente mit 3 MeV-neutronen aus der D(d, n)3He-kernreaktion

An efficient low threshold detector system with space charge discrimination for neutron time-of-flight spectrometry at a pulsed 500 kV-cascade-generator is described. The comparison between single-tube- and twin-tube-detector shows the advantages of the single-tube-arrangement. For neutron energies from 0.6 to 3.2 MeV the detection efficiency of a NE-213 liquid scintillator at a recoil proton energy threshold of 650 keV has been measured by n-p scattering in polyethylene with and without n-γ discrimination. The experimental results were compared with calculated efficiencies and a good agreement is obtained for the energy dependence as well as for the absolute values of the detection efficiency. The application of this detector system is demonstrated by both the neutron time-of-flight spectrometry of the 9Be(d,n)10B-reaction and n-p scattering in polyethylene.