PHOTONUCLEAR PHYSICS MODELS, SIMULATIONS, AND EXPERIMENTS FOR NUCLEAR NONPROLIFERATION

摘要

This work illustrates a methodology based on photon interrogation and coincidence counting for determining the characteristics of fissile material. The feasibility of the proposed methods was demonstrated using the Monte Carlo-based MCNPX/MCNP-PoliMi code system capable of simulating the full statistics of the neutron and photon field generated by the photon interrogation of fissile and non-fissile materials with high-energy photons. These simulations were compared to the prompt time-of-flight data taken at the Idaho Accelerator Center immediately following the photon interrogation of a depleted uranium target. The results agree very well with the measured data for interrogation with 15-MeV endpoint bremsstrahlung photons at two different detector separation distances.