Fast Neutron Time Encoding Imaging for Special Nuclear Material Detection

Rising concerns in monitoring the presence and movement of special nuclear material (SNM) highlight the need for improved reliable neutron detection methods for large standoff distances. To be inco rporated as a deployable system , standoff detection methods must be efficient and cost - effective, feature good signal to background discrimination a nd accurately identify the presence and location of material. By decoupling the desired features of a standoff detector from each other, they can b e optimized independently. Time - encoded imaging (TEI) separates source position and signal to background disc rimination from the detector through the use of time - modulated collimators. This allows high angular resolution while greatly increasing efficiency and energy resolution by relying on single scatters of fast neutron and gammas in a large scintillator volum e. This paper present s results using two prototype detectors based on time - encoded imaging for fission neutron detection in realistic standoff scenarios. A new extension to high - resolution two - dimensional imaging is also presented. These results showcase the ease of deployment for TEI detector systems due to their lower cost, reduced complexity, and scalability.