Imaging and spectroscopy of fission neutrons with the FNIT experiment

The Fast Neutron Imaging Telescope (FNIT) instrument is a NA-22 funded project for the design, construction, calibration and modeling of an instrument specifically tailored to measure and identify sources of fission neutrons - a key signature of Special Nuclear Material (SNM). A neutron detector that is sensitive to this energy range is of utmost importance to stop the proliferation of these materials. The proof of concept of this instrument has been successfully demonstrated with a limited FNIT prototype. After being constructed and fine-tuned at the University of New Hampshire (UNH), the prototype was calibrated with quasi-monoenergetic neutron beams at Crocker Nuclear Laboratory. Extensive Monte Carlo calculations are currently in the advance stages for the modeling of FNIT. These simulations, along with the calibration and tests that have been performed with a ²⁵²Cf source at UNH, will be used to determine the instrument efficiency and response. Further instrument simulations will allow us to determine the best methods for spectral and imaging de-convolution. Ultimately, these methods will be implemented into ldquoon-linerdquo software being designed for real-time analysis algorithms to be used in conjunction with a fully populated, portable neutron telescope. We present the most recent laboratory and instrument modeling results.