A review of optical diagnostic techniques used to identify uranium spectral signatures

Spectroscopic detection of signatures produced by Nuclear Weapons of Mass Destruction (NWMD) is essential for maintaining national security and countering nuclear proliferation. Through non-invasive measurement techniques it is possible to remotely monitor an area and confirm or deny the use of nuclear materials in explosives. Given that all elements have a unique atomic and molecular emission signature, explosive compositions can be determined by making comparisons to known spectral emission data. Atomic and molecular signatures can only be detected at early times during an explosive event when high-energy plasmas are formed. Additionally, the chemical and physical properties, including temperatures and compositions, of these short lifetime plasmas rapidly evolve as the event moves forward in time. For these reasons it is of interest to develop a system capable of gathering and accurately tracking temporal spectral information at early times in an excitation event. This research aims to implement an optical diagnostic system capable of performing time-resolved emission spectroscopy to accurately identify actinide core signatures in the UV-visible regime. Primary system components included two different material spark chambers, one dust cloud combustion chamber, spectrometer, and two different charge coupled device cameras capable of recording time-resolved spectra. Time-resolved spectra are also produced with a rotating mirror assembly capable of mechanically streaking the emitted light. Multiple methods of material excitation have been investigated including exploding brass bridgewires, graphite electrode sparks containing powders, uranium wire electrode sparks, and ignition of various metal powders to generate burning dust clouds. High-speed images of two out of the three excitation methods are reported. Additionally, the initial gas environments and pressures will be varied to influence the material excitation process.LimitedAuthor requested closed access (OA after 2yrs) in Vireo ETD syste