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  • 1
    Electronic Resource
    Electronic Resource
    Measuring the dead time of an x-ray spectrometer by means of the first- and second-order reflections method (1984)
    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 13 (1984), S. 44-45 
    Details
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The dead time of a Philips PW 1410 x-ray fluorescence spectrometer with a photon detector has been calculated employing intensities of first- and second-order reflections. The spread of the values obtained can be considered very satisfactory in the light of the experimental difficulties inherent in this method.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/xrs.1300130109
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  • 2
    Electronic Resource
    Electronic Resource
    A modification of Kramers' law for the x-ray continuum from thick targets (1984)
    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 13 (1984), S. 60-63 
    Details
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The intensity of an x-ray continuum had been generated theoretically for incident electron energies between 10 and 45 keV, radiated photon energies between 2 and 40 keV and over the whole range of atomic numbers (from Z = 1 to 100). For these cases a relatively simple expression was found which shows the dependence of continuous radiation on the atomic number, incident electron energy and radiated energy. In order to compare observed intensities with this expression, we have made corrections for self-absorption in the target, for loss of ionization due to backscatter and for absorption by the exit window of an x-ray tube. Our expression provides a better description of experimental observations than dose Kramers' equation.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/xrs.1300130205
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  • 3
    Electronic Resource
    Electronic Resource
    Intensity for cubic particles in x-ray fluorescence analysis (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 14 (1985), S. 2-7 
    Details
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Particle size effects constitute a major source of error in the x-ray fluorescence of granular material. Different models have been proposed to account for the influence of particle size on the characteristic x-ray intensity leaving the sample. Important points in these models are the granular distribution from each grain. Berry et al. proposed a model which is in reasonable agreement with experimental values. In this work, fluorescent intensity calculations for a cubic particle with different geometries were carried out. The intensity values obtained through this model were compared with the Berry et al. model. There is better agreement with the experimental values when the expression obtained is used in order to find the total fluorescent intensity using heterogeneous samples consisting of fluorescent and non-fluorescent components of particle size d.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/xrs.1300140103
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  • 4
    Electronic Resource
    Electronic Resource
    Theoretical assessment of the coefficients φ(0) and γ0 of the Gaussian φ(ρz) curves (1987)
    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 16 (1987), S. 27-32 
    Details
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: New analytical expressions for the surface ionization, φ(0), and the amplitude of the ionization distribution, φ(ρz), in the surface γ0, are derived which take into account physical reality. Values of these parameters are obtained using these expressions and compared with previous models and experimental determinations. The proposed expressions show very good agreement with measured values.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/xrs.1300160107
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  • 5
    Electronic Resource
    Electronic Resource
    Assessment of the gaussian φ(ρz) curves in quantitative electron probe microanalysis without optimization of the parameters (1987)
    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 16 (1987), S. 243-248 
    Details
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: A new expression for the parameter β of the φ(ρz) curves is developed and the calculated K intensity ratios are compared with the corresponding experimental K, compiled in previous publications. The results show a mean value for K/K of 1.003, a standard deviation of 4.8% and an asymmetry of 1.01 with respect to unity.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/xrs.1300160604
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  • 6
    Electronic Resource
    Electronic Resource
    Evaluation of the main atomic number, absorption and fluorescence correction models in quantitative microanalysis (1987)
    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 16 (1987), S. 249-254 
    Details
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The principal LAF correction models have been tested for a set of 471 experimental values from heavy element binary specimens (Z 〉 12) and another set of 116 determinations for oxides, both compiled by Love et al. New fluorescence correction models have been developed, based on a Gaussian distribution of ionizations. The atomic number, absorption and fluorescence correction models corresponding to this distribution are the best fitting ones.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/xrs.1300160605
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  • 7
    Electronic Resource
    Electronic Resource
    Absolute method for determination of metallic film thickness by X-ray fluorescence (1988)
    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 17 (1988), S. 43-46 
    Details
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: An absolute method for the determination of the thickness of a nickel film on iron has been developed. The mass absorption coefficient of nickel for the effective wavelength has been determined empirically and mathematically. The found values were in agreement. To perform this method only one intensity measurement of the fluorescent substrate emission is required (Fe Kα). The method was tested using iron sheets with different thicknesses of nickel obtained by chemical deposition. Thicknesses between 6 and 25 μm produced relative differences from gravimetric values of 1.8-1.1%.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/xrs.1300170203
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  • 8
    Electronic Resource
    Electronic Resource
    Absolute x-ray fluorescence method for the determination of metal thicknesses by intensity ratio measurements (1990)
    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 19 (1990), S. 93-96 
    Details
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: An absolute method for the determination of the thickness of a metal film deposited on a metallic substrate is described. The method is based on the measurement of fluorescent intensity ratios for two lines from the substrate element. Titanium sheets covered with nickel layers of different thicknesses (between 3 and 22 μm) were employed to test the method. Intensity measurements were performed using different excitation modes and detection systems. Additionally, the proposed method can be employed to determine the density of the deposited material or the incident angle of primary radiation and take-off angle if the deposited metal film thickness is known. The method can be applied by using the intensity ratios of two lines generated through electron vacancies in the same shell.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/xrs.1300190303
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  • 9
    Electronic Resource
    Electronic Resource
    A theoretical procedure to determine coefficients from the Rasberry-Heinrich calibration curve in XRF spectroscopy (1981)
    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 10 (1981), S. 74-77 
    Details
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Relative X-ray fluorescent intensity data have been generated numerically for binary samples under mono-chromatic excitation in those cases of absorption plus enhancement that are dealt with in this work. These data were fitted to the empirical Rasberry-Heinrich equation, keeping both coefficients different from zero, since from our numerical calculations it is shown that in most cases the best fit is achieved when A ≠ 0. Furthermore, this approach shows that a third coefficient introduced into the empirical equation improves the fitting. The aforementioned results suggest that the empirical equation could be deduced from the theoretical equation of fundamental parameters under suitable approximation. The result is an equation similar to that of Rasberry and Heinrich, from which analytical approximated coefficients are obtained. It is then possible to calculate a calibration curve using fundamental parameters values.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/xrs.1300100208
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  • 10
    Electronic Resource
    Electronic Resource
    Backscattering of 10-35 keV electrons from thick targets at normal incidence (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 18 (1989), S. 229-234 
    Details
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Energy distributions of backscattered electrons were obtained by Monte Carlo simulations for a wide range of elements for electron beams at normal incidence and with energies Eo between 10 and 35 keV. These spectra were compared with experimental data and with a theoretical expression. An analytical expression was fitted to the simulated data. An expression for the backscattered electron coefficient η as a function of atomic number Z and incident energy Eo was obtained. A model for η and the energy distribution of backscattered electrons for multielement samples is suggested.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/xrs.1300180510
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