Nuclear resonance fluorescence and effective Z determination applied to detection and imaging of special nuclear material, explosives, toxic substances and contraband

摘要

Nuclear resonance fluorescence (NRF) provides a signal that is unique and present for almost all nuclei with Z > 2. This uniqueness would enable, for example, the discrimination between ~(235)U from ~(238)U. Explosives can be detected by the characteristic signatures of carbon, nitrogen and oxygen and their respective densities in a common space. Effective Z algorithms (EZ-3D) have been developed for the examination of the non-resonant spectrum of back-scattered photons that yield a signal with very high contrast between materials of moderately different Z. Both the NRF and EZ-3D non-intrusive inspection techniques provide a three dimensional display of the contents of a container; respectively, the isotopic concentrations, and effective Z and mass. NRF combined with EZ-3D provides the possibility for rapid scanning of seagoing containers, trucks and other vehicles. They do so in short times with high detection probabilities for SNM, explosives and other contraband and with low false alarms.