Fluorine K-Edge X-Ray Absorption Spectroscopy for Glasses, Minerals and Salts

Very little data exists in the literature for absorption spectra at some low-energy X-ray edges, particularly the fluorine K-edge (~690 eV). Though it is not possible to obtain extended X-ray absorption fine structure (EXAFS), considerable information is contained in the X-ray absorption near edge structure (XANES). Over 100 materials were measured at the Canadian Light Source Spherical Grating Monochromator beamline at the F K-edge at room temperature. This presentation describes the lessons-learned for obtaining high-quality XANES at the fluorine edge using both total electron yield (TEY) and fluorescence modes. A number of materials of interest for nuclear waste management were measured, including F-containing oxide glasses, molten salt relevant pure fluoride glasses and compounds, and F-containing minerals with potential as waste forms. Specifically, findings on more than 40 oxide glasses (silicate, borosilicate, aluminosilicate, phosphate, borate, etc.), >30 metal fluorides binaries and ternaries including rare earth fluorides and oxyfluorides, and >20 F-containing natural minerals are presented. Preliminary insights and trends are offered for binary fluorides, mineral phases and environments, and glasses. Possible future uses of this promising technique are also discussed.