A directional neutron detector based on a recoil proton telescope was investigated by experimental approach. The detector showed a directionality not only for 14-MeV neutrons but also for fission and 2.4-MeV neutrons. Due to a good rise-time pulse-shape discrimination capability of a CsI(Tl) scintillator, a recoil proton energy spectrum was clearly observed in high gamma-ray background. At a detector angle of 21° with respect to the neutron incident direction, the counts corresponding to the high energy neutron became a half of those at 0°. A major source for reducing the signal-to-noise ratio was identified to be the energetic protons via the (n,p) reaction in the CsI(Tl) scintillator.
