Secondary electron energy deposition in thin polymeric films for neutron-photon discrimination

Abstract

Thin polymeric films are evaluated in this research as a potential replacement technology for radiation portal monitors where specific attention is given to the physical basis for neutron-photon discrimination. It is shown that the difference in the energy deposition mechanics from charged particle reaction products and from the Compton scattered electrons allows for the effective discrimination between neutrons and gammas. One goal of this study was to establish optimal thickness for polymeric films that maximize the neutron interactions and simultaneously minimize the measured interaction of photons. Polymeric films ranging from 15 μm to 600 μm containing 6LiF were fabricated and tested for their capability to satisfy criteria established by the Department of Homeland Security. Results from Monte Carlo simulations with the GEANT4 code and data from measurements confirm the technical basis for our proposed understanding of neutron-photon discrimination characteristics for thin films. © 1963-2012 IEEE.