MONTE-CARLO SIMULATION OF THE RESPONSE OF NAI SCINTILLATOR TO MEDIUM-ENERGY NEUTRONS

A layered NaI scintillation detector (total thickness = 30.6 cm) was e xposed to tagged neutrons at the Los Alamos Meson Physics Facilty. The neutrons were approximately monoenergetic at ten energies in the rang e 36-709 MeV. The energy loss of the neutrons in the detector was subs equently simulated using a Monte Carlo program, which incorporated the HETC, EGS, and MORSE computer codes. The agreement between the experi ment and the simulation for the detection efficiency was within 35%. A comparison of the measured and calculated energy-loss spectra showed differences generally within 50%. Details of the detector geometry, th e Monte Carlo simulation, and the comparison of the data and the simul ation are presented.