The Department of Chemistry invites you to its departmental seminar today, Monday, Sept. 14, at 4:10 p.m. in Fulmer Hall, room 201.
Dr. George Havrilla from the Los Alamos National Lab will present, Actinide Characterization using X-ray Fluorescence.
Abstract: X-ray fluorescence (XRF) is an elemental analysis technique which utilizes X-ray excitation to create X-ray emission from samples to provide both qualitative and quantitative determination of material composition. While XRF is an established method within the cement, steel and mineral industries, its use within the nuclear field have ranged from limited to nonexistent. New applications of XRF within nuclear safeguards and nuclear forensics demonstrates new capabilities based on X-ray optics which have only recently enjoyed commercial availability. Polycapillary optics provide high photon flux in spatially resolved X-ray excitation spots of several hundred micrometers to nearly 10 micrometers. Such highly focused X-ray beams can interrogate materials to probe elemental distribution over 10’s to 1000’s of micrometers in x and y directions to create elemental maps of the material composition. Such elemental imaging offers insights into the spatial distribution of the target analytes in a wide range of material types. In particular, the spatial distribution of uranium and plutonium in soil and spent nuclear fuel can provide critical information for both safeguards and forensics applications. Adding a polycapillary to the detector enables one to create a confocal probe which can generate 3D elemental images within a material such as soil particles. Identifying the distribution of Pu within soil and elements associated with it can provide information on the source and possible formation of the Pu in the contaminated soil. Extending this concept to the high energy K lines of U and Pu opens up through container wall detection of these elements. Elemental maps of U and Pu through Zircaloy cladding can be easily obtained without much interference using UHEXRF (ultrahigh energy XRF, >80keV). Besides elemental information, oxidation state plays a critical role in the environmental presence of actinides. High spectral resolution microcalorimeter detectors with resolution around 5 eV can detect elemental X-ray emission shifts associated with oxidation state of the element down to 1 eV. Overall XRF offers unique capabilities for measuring actinide elements. LA-UR-15-26737.
