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Aragón Garbizu, Carlos

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Aragón Garbizu

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Carlos

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Ciencias

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InaMat2. Instituto de Investigación en Materiales Avanzados y Matemáticas

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0000-0003-1737-6402

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433

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Now showing 1 - 6 of 6
  • PublicationOpen Access
    Experimental Stark widths and shifts of MnII spectral lines
    (Oxford University Press, 2019) Manrique Rosel, Javier; Aragón Garbizu, Carlos; Aguilera Andoaga, José Antonio; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2; Ciencias
    Stark widths and shifts of MnII lines with wavelengths in the range 2300-3500 Å have been measured by laser-induced breakdown spectroscopy. The use of fused glass samples with varying Mn concentrations has allowed minimization of the error due to self-absorption in the Stark width measurements, which has made it possible to include resonance lines in the study. The laser-induced plasmas are characterized along their temporal evolution, showing electron densities in the range (0.60-6.75)×1017 cm-3 and temperatures in the range 11 000-13 900 K. The results are compared with experimental and theoretical values available in the literature.
  • PublicationOpen Access
    CSigma graphs: a new approach for plasma characterization in laser-induced breakdown spectroscopy
    (Elsevier, 2014) Aragón Garbizu, Carlos; Aguilera Andoaga, José Antonio; Física; Fisika
    A generalization of curves of growth called CSigma (Cσ) graphs, which allows including several lines of various elements in the same ionization state at different concentrations, is proposed for laser-induced breakdown spectroscopy (LIBS) experiments. The method relies on the Boltzmann, Saha and radiative transfer equations for plasmas in local thermodynamic equilibrium. Cσ graphs are based on the calculation of a line cross section σl for each of the experimental data, starting from the atomic data of the line, the temperature and the electron density. A model of homogeneous plasma, applied separately for neutral atoms and ions, is used. A limit of validity is established for this model. Experimental Cσ graphs have been obtained using fused glass samples containing Fe, Mn, Mg, Si and Cr. By fitting experimental Cσ graphs to calculated curves, the LIBS system becomes characterized by a set of four parameters βA, Nl, T, Ne, different for neutral atoms and ions. Starting from this characterization, the intensity and self-absorption of a given spectral line of an element at a certain concentration may be predicted, provided that its atomic data are known and the limit of validity is not exceeded.
  • PublicationOpen Access
    Experimental stark widths and shifts of V II spectral lines
    (Oxford University Press, 2020) Manrique Rosel, Javier; Díaz Pace, D. M.; Aragón Garbizu, Carlos; Aguilera Andoaga, José Antonio; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2; Ciencias
    We have measured the Stark widths and shifts of V II spectral lines in the wavelength range 2000-4200 Å belonging to 75 multiplets. The spectra are emitted by laser-induced plasmas generated from fused glass discs prepared by borate fusion. The electron density and temperature are in the ranges (0.72-6.5) × 1017 cm-3 and (11 000-14 900) K, respectively. To avoid self-absorption, we have used seven samples with vanadium concentrations selected by the CSigma graph methodology. This has allowed to include strong and weak lines in the study, including resonance and forbidden lines. The experimental widths and shifts are compared with theoretical values available in the literature.
  • PublicationOpen Access
    Direct analysis of aluminum alloys by CSigma laser-induced breakdown spectroscopy
    (Elsevier, 2018) Aragón Garbizu, Carlos; Aguilera Andoaga, José Antonio; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2; Ciencias
    We report the application of CSigma laser-induced breakdown spectroscopy (Cσ-LIBS) to quantitative analysis of aluminum alloys without sample preparation. Cσ-LIBS simplifies strongly the conventional calibration procedure of LIBS, replacing it with a characterization stage performed from the spectrum of a single standard sample. The aim of this work has been to provide a complete evaluation of the use of Cσ-LIBS for direct analysis by obtaining its figures of merit, including precision and limits of detection. Ten elements (Si, Fe, Cu, Mn, Mg, Cr, Ni, Zn, Ti and Ca) are determined in a set of six certified samples with a wide range of concentrations, from percent down to μg/g levels. The average precision is 8.0% for concentrations higher than 0.1 wt% and 13% for concentrations between 0.1 wt% and 0.01 wt%. The limits of detection are in the range 1.4–9.7 μg/g.
  • PublicationOpen Access
    Experimental Stark widths and shifts of Cr II spectral lines
    (Oxford University Press, 2013) Aguilera Andoaga, José Antonio; Aragón Garbizu, Carlos; Manrique Rosel, Javier; Física; Fisika
    Stark widths and shifts of Cr II lines with wavelengths in the range 2000–3500 Å have been determined by laser-induced breakdown spectroscopy. The spectra have been measured at different instants of the plasma evolution from 0.6 to 3.4 μs, at which the temperature and electron density are in the ranges 12 000–16 300 K and (0.89–8.2) × 10¹⁷ cm ˉ³, respectively. The laser-induced plasmas have been generated from three fused glass samples with different chromium concentrations, selected to control the self-absorption of the lines. The Stark widths and shifts are compared with the experimental and theoretical data available in the literature.
  • PublicationOpen Access
    Method for measurement of transition probabilities by laser-induced breakdown spectroscopy based on CSigma graphs. Application to Ca II spectral lines
    (Elsevier, 2015) Aguilera Andoaga, José Antonio; Aragón Garbizu, Carlos; Manrique Rosel, Javier; Física; Fisika
    We propose a method for determination of transition probabilities by laser-induced breakdown spectroscopy that avoids the error due to self-absorption. The method relies on CSigma graphs, a generalization of curves of growth which allows including several lines of various elements in the same ionization state. CSigma graphs are constructed including reference lines of an emitting species with well-known transition probabilities, together with the lines of interest, both in the same ionization state. The samples are fused glass disks prepared from small concentrations of compounds. When the method is applied, the concentration of the element of interest in the sample must be controlled to avoid the failure of the homogeneous plasma model. To test the method, the transition probabilities of 9 Ca II lines arising from the 4d, 5s, 5d and 6s configurations are measured using Fe II reference lines. The data for 5 of the studied lines, mainly from the 5d and 6s configurations, had not been measured previously.