ANDRE SANTOS BARROS DA SILVA

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20173
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Âmbito: Internacional × Autor: LUIS GALLEGO MARTINEZ ×

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    Artigo IPEN-doc 24174
    X-ray diffraction analysis of KY3F10 nanoparticles doped with Nd and preliminary studies for its use in high-dose radiation dosimetry
    2017 - ICHIKAWA, RODRIGO U.; LINHARES, HORACIO M.S.M.D.; SILVA, ANDRE S.B. da; TEIXEIRA, MARIA I.; RANIERI, IZILDA M.; TURRILLAS, XAVIER; MARTINEZ, LUIS G.
    In this work, the structure and microstructure of Nd:KY3F10 nanoparticles was probed using X-ray synchrotron diffraction analysis. Rietveld refinement was applied to obtain cell parameters, atomic positions and atomic displacement factors to be compared with the ones found in literature. X-ray line profile methods were applied to determine mean crystallite size and crystallite size distribution. Thermoluminescent (TL) emission curves were measured for different radiation doses, from 0.10kGy up to 10.0kGy. Dose-response curves were obtained by area integration beneath the peaks from TL. The reproducibility of the results in this work has shown that this material can be considered a good dosimetric material.
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    Artigo IPEN-doc 24172
    Structural and microstructural analysis of the U-GD-O system using X-ray diffraction data
    2017 - DARIN, GASPAR; IMAKUMA, KENGO; MARTINEZ, LUIS G.; TURRILAS, XABIER M.; ICHIKAWA, RODRIGO U.; SILVA, ANDRE S.B.; DURAZZO, MICHELANGELO; RIELLA, HUMBERTO G.; URANO, ELITA
    Gadolinium is one of the best neutron absorber materials and its usage can be considered as a burnable poison for Light Water Reactors (LWR) and as a sacrificial material in Sodium Fast Reactor (SFR). Most of the experiments in the literature focus on nuclear fuel with up to 12 wt% Gd2O3. Recently, the phase diagram and melting point has been investigated for high contents of Gd2O3 in the U-Gd-O system, that means a solid solution of the composition (U1-x, Gdx)O2 for 0
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    Artigo IPEN-doc 24140
    Structural and microstructural characterization of U3Si2 nuclear fuel using X-ray diffraction
    2017 - ICHIKAWA, RODRIGO U.; GARCIA, RAFAEL H.L.; SILVA, ANDRE S.B. da; TURRILLAS, XAVIER; SALIBA-SILVA, ADONIS M.; LIMA, NELSON B.; MARTINEZ, LUIS G.
    In this work, two uranium silicide powdered samples, containing 67% and 42 mol% of Si, were analyzed using X-ray diffraction (named as 67Si and 42Si). For structural characterization, Rietveld refinement was used to estimate cell parameters, volume fraction (weight percent) of crystalline phases and atomic positions. For the main phases, X-ray line profile analysis (XLPA) was used to estimate mean crystallite sizes and microstrains. The 67Si sample presents higher content of USi2 (tetragonal) and the 42Si sample presents higher content of U3Si2 (tetragonal) as identified and calculated from the XRD profiles. Overall there are no appreciable structural changes and the parameters refined are in good accordance with the ones reported in the literature. Mean crystallite sizes determined by XLPA revealed small crystallites of the order of 101 nm and low microstrain for all samples.