A large area plastic scintillator detector array for fast neutron measurements

A large area plastic scintillator detector array (∼1×1m2) has been set up for fast neutron spectroscopy at the BARC-TIFR Pelletron laboratory, Mumbai. The energy, time and position response has been measured for electrons using radioactive sources and for monoenergetic neutrons using the 7Li(p,n1)7Be*(0.429MeV) reaction at proton energies between 6.3 and 19 MeV. A Monte Carlo simulation of the energy dependent efficiency of the array for neutron detection is in agreement with the 7Li(p,n1)(p,n1) measurements. The array has been used to measure the neutron spectrum, in the energy range of 4–12 MeV, in the reaction C12+Nb93 at E(C12)=40MeV. This is in reasonable agreement with a statistical model calculation.