Simulated Neutron Response Functions of Phoswich-Type Neutron Detector and Thin Organic Liquid Scintillator

Abstract

Neutron response functions of a phoswich neutron detector and thin organic liquid scintillator were simulated using the multi-purpose Monte Carlo code MCNPX, incorporating functions of light outputs, energy resolutions, and unifor- mity of scintillation. The simulated response functions were verified by response-function measurement for high-energy neutrons produced by bombarding thin lithium targets with 10- to 80-MeV protons. Our procedures can simulate the response functions of the organic liquid scintillator and the phoswich neutron detector without limits of neutron ener- gies, materials, or geometries. Based on the evaluated neutron response functions, we obtained neutron energy spectra using an unfolding method. One is the high-energy neutron spectrum at the aviation altitude, 10.8 km, and the other is at an intense fast neutron field for biological study in the National Institute of Radiological Sciences.