Thomas Bristow, Robert Downs, Marc Gailhanou, Franck Marchis, Douglas Ming, Richard Morris, Vicente Armando Solé, Kathleen Thompson, Philippe Walter, Michael Wilson, Albert Yen and Samuel Webb, NASA Ames Research Center, Moffett Field, CA [email protected], SETI Institute, Mountain View, CA, Univ. of Arizona, Tucson AZ, IM2NP, Université Paul Cézanne, Marseille, France, NASA Johnson Space Ce...

Total and partial fluorescence yield (PFY) L-edge x-ray absorption spectra differ from the transmission x-ray absorption spectra (XAS) through state-dependent fluorescence yield across the XAS. For 3d to 3d in octahedral symmetry we apply simulations of PFY and XAS and show how the atomic 2p3d Coulomb exchange parameter Gpd governs the differences in the L3/(L2+L3) branching ratio between PFY a...

Measurements of the cosmic-ray air-shower fluorescence at extreme energies require precise knowledge of atmospheric conditions. The absolute calibration of the cosmic-ray energy depends on the absorption of fluorescence light between its origin and point of its detection. To reconstruct basic atmospheric parameters we review a novel analysis method based on twoand multi-angle measurements perfo...

Waste materials from mining tailings, often contain significant amounts of potentially valuable minerals. This study aimed at unearthing the minerals in Ijero Ekiti mine tailings. The tailing samples were randomly collected five locations area. analyzed for selected physico-chemical parameters: pH values, electrical conductivity, chloride, organic matter and X-Ray Fluorescence Spectrometry (XRF...

Micro X-ray fluorescence ~MXRF! offers the analyst a new approach to materials characterization. The range of applications is expanding rapidly. Single point analysis has been demonstrated for nanoliter volumes with detection limits at the 0.5 ng level. MXRF can be used as an element specific detector for capillary electrophoresis. Elemental imaging applications include analysis of sample corro...

The development of highly efficient X-ray optics has allowed the development of bench-top XRF systems which have high intensity X-ray beams with diameters ranging from 10 micrometres through to a few millimetres. Coupled with integrated high magnification optical cameras, these systems are ideally suited to the needs of the forensic scientist. A microscopic particle from a crime scene can be an...

In experiments preliminary to the design of an X-ray-excited optical luminescence (XEOL)-based chemical mapping tool we have used X-ray micro (4.5 × 5.2 μm) and macro (1 × 6 mm) beams with similar total fluxes to assess the effects of a high flux density beam of X-rays at energies close to an absorption edge on inorganic surfaces in air. The near surface composition of corroded cupreous alloys ...

We show that at the standard laboratory wavelength of CuKa the scattering factors of Cu and NiosFeo2 are identical, thereby making it impossible to distinguish the boundary of the Cu spacer layer in a Cdpermalloy spin valve structure from grazing incidence x-ray reflectivity curves. Use of grazing incidence fluorescence, in conjunction with x-ray reflectivity provides sufficient information to ...