Site-Specific Morphological and Chemical Analysis of Nuclear Materials

Nuclear forensics requires accurate identification of distinguishing material characteristics to delineate the material’s origin-to-interdiction information. We developed the focused ion beam (FIB) methodology to reveal entrapped material clues such as internal morphological and chemical features within the surface/subsurface and bulk of nuclear materials. Our recent effort also established the capability of using the FIB-based micromanipulation technique to select, isolate, and extract a site-specific microscopic feature from bulk plutonium (Pu) and uranium (U) materials. Using a combination of scanning electron microscopy (SEM), transmission electron microscopy, three-dimensional (3D) spatial modeling, and synchrotron-based X-ray spectromicroscopy, we identified distinguishing morphological and chemical characteristics that are attributable to the material’s provenances. Variations in the internal chemical composition and morphological structure were found to occur between materials from different origin, processing, and environmental exposures. The information is of potential use in identifying material characteristics related to the provenance, process, and pathways of interdicted nuclear materials.