| After the attack on the World Trade Center, homeland security has turned into a major concern internationally. Effort is being made to find accurate, efficient, and practical ways to prevent smuggling of Special Nuclear Materials (SNM). Although passive techniques may be equally accurate in some cases, active interrogation methods offer unique flexibility: the energy and intensity of the interrogating radiation can be adjusted to provide an appropriate response intensity, the energy of the interrogation radiation can be adjusted to generate different responses from different nuclides, and in contrast to passive methods, active interrogation techniques can be applied to both low- and high-density materials, and even materials shielded with high-density materials.;This work will examine detection of SNM by studying two active interrogation methods: photon induced fission in fissile materials and Nuclear Resonance Fluorescence (NRF) reactions between incident photons and nuclei in target materials. This effort includes system simulations using Monte Carlo methods, digital spectroscopic measurement system development, and experimental demonstrations of the two detection techniques. |
