Year
2015
Abstract
Assessment of fissile materials is important to the achievement of nonproliferation goals and to enhancing the safety and security of nuclear facilities. Nuclear materials can be characterized by measurement of prompt and delayed neutrons and photons emitted in spontaneous or induced fission events. A compact neutron detector was designed using the plastic scintillator EJ-299- 33A, with neutron/photon pulse shape discrimination properties. Neutron responses of the detector were measured using an accelerator-based monoenergetic neutron source. The detector was tested in mixed neutron/photon fluxes, and digital pulse shape analysis was implemented to segregate the scintillation signals induced by neutrons from those induced by photons. Wavelets were applied to treat the neutron response functions. The responses were used in a spectral unfolding technique based on polynomial fitting. We discuss neutron yield measurements for DD and DT fusion neutron sources and a plutonium-beryllium source.