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Chemical state
About: Chemical state is a research topic. Over the lifetime, 2378 publications have been published within this topic receiving 78183 citations.
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TL;DR: In this paper, a thermal-field emission type electron gun set to a low-energy range (<1 keV) is used to obtain a beam size less than 100 nm in diameter.
4 citations
TL;DR: XPS studies indicate that the binding energies of the Zr3d electron increase with increasing oxygen deficiency in the surface layer and decrease with its decrease as mentioned in this paper, and ZrO2−x is probably metallic zironium.
Abstract: XPS studies indicate that on the surfaces of untreated ZrCr2 and ZrCr2H3.6 zirconium is detected as ZrO2, ZrO2−x and, probably, metallic zironium. Binding energies of the Zr3d electron increase with increasing oxygen deficiency in the surface layer and decrease with its decrease.
4 citations
TL;DR: In this paper, a 2D speciation map was constructed from micro-focus X-ray fluorescence and XANES data, in an effort to maximize sensitivity to the U oxidation state at the U L 3-edge, applied to a suite of synthetic Chernobyl lava specimens.
Abstract: Uranium speciation and redox behaviour is of critical importance in the nuclear fuel cycle. X-ray absorption near-edge spectroscopy (XANES) is commonly used to probe the oxidation state and speciation of uranium, and other elements, at the macroscopic and microscopic scale, within nuclear materials. Two-dimensional (2D) speciation maps, derived from microfocus X-ray fluorescence and XANES data, provide essential information on the spatial variation and gradients of the oxidation state of redox active elements such as uranium. In the present work, we elaborate and evaluate approaches to the construction of 2D speciation maps, in an effort to maximize sensitivity to the U oxidation state at the U L3-edge, applied to a suite of synthetic Chernobyl lava specimens. Our analysis shows that calibration of speciation maps can be improved by determination of the normalized X-ray absorption at excitation energies selected to maximize oxidation state contrast. The maps are calibrated to the normalized absorption of U L3 XANES spectra of relevant reference compounds, modelled using a combination of arctangent and pseudo-Voigt functions (to represent the photoelectric absorption and multiple-scattering contributions). We validate this approach by microfocus X-ray diffraction and XANES analysis of points of interest, which afford average U oxidation states in excellent agreement with those estimated from the chemical state maps. This simple and easy-to-implement approach is general and transferrable, and will assist in the future analysis of real lava-like fuel-containing materials to understand their environmental degradation, which is a source of radioactive dust production within the Chernobyl shelter.
4 citations
TL;DR: In this paper , the ionic influence, especially the chemical bond of F and Zn, on the acid resistance of dentin were investigated by particle induced X-ray / gamma-ray emission, Xray diffraction, X -ray photoelectron spectroscopy, and Xray absorption spectrography.
4 citations
03 Apr 1993-Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms
TL;DR: An undulator-radiation-excited X-ray fluorescence analysis system has been developed at an undulator beamline of the Photon Factory in this article, where the chemical state of boron implanted with a high dosage of BF 2 + into Si(100) was analyzed by measuring both the B Kα soft Xray emission (SXE) and X-rays absorption near edge structure (XANES) with fluorescence detection.
Abstract: An undulator-radiation-excited X-ray fluorescence analysis system has been developed at an undulator beamline of the Photon Factory. As an analytical application demonstrating the capabilities of this system, the chemical state of boron implanted with a high dosage of BF 2 + into Si(100) was analyzed by measuring both the B Kα soft X-ray emission (SXE) and X-ray absorption near edge structure (XANES) with fluorescence detection. Comparing the SXE and fluorescence XANES spectra of B doped in Si with relevant reference boron compounds, it is confirmed that the chemical state of the B atoms as implanted in Si is metallic despite the fact that B is implanted as BF + 2 . Oxidation of B doped in Si by annealing at 900° C in atmosphere is also observed.
4 citations