Detection Efficiency of Plastic Scintillator for Neutron Energies 4 to 76 Mev

The neutron detection efficiency of plastic scintillator counters 15 cm thick has been determined for neutron energies from 4 to 76 Mev. Neutrons in this energy range were obtained by scattering a 205‐Mev neutron beam from a hydrogen target. A proton‐range telescope selected the forward‐scattered protons from the n‐p reaction, thus monitoring the flux of monoenergetic neutrons scattered in a prescribed direction. Near 10 Mev the efficiency is 30%, and it slowly decreases to 20% at 76 Mev.