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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 12 (1983), S. 153-162 
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Cross-sections for bremsstrahlung production in thin films may be derived theoretically only if certain approximations are made or if there is recourse to numerical techniques. In this paper, two approximate equations, one based on the Sommerfeld theory and the other on the Bethe-Heitler theory, are assessed for their accuracy in predicting cross-sections differential in photon energy and emergence angle when a thin foil target is bombarded with electrons with energies between 40 and 100 keV. Experimental data are presented from eight different target materials and these are processed initially to make comparisons between experimental and theoretical spectral shapes and subsequently to compare observed and predicted absolute cross-section values. Except for the heaviest target material (Au), the Bethe-Heitler theory provided a satisfactory description of all experimental observations. In contrast, the Sommerfeld theory provided a significantly inferior description of spectral shapes and consistently overestimated absolute cross-sections by 15-20%.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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  • 2
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Two approximate theories are considered for the production of characteristic x-rays when thin foil targets are bombarded with electrons with energies between 40 and 100 keV. One, due to Kolbenstvedt, is semi-classical in nature whilst the other, due to Bethe, contains two parameters which are normally adjusted empirically. Data from six different target materials are presented, but because errors in experimentally derived absolute cross-sections are large, a comparison is made between theoretical and observed ratios of characteristic Kα photons to bremsstrahlung photons in a 20 eV channel directly beneath the peak. By adjusting the Bethe parameters and using a modified Bethe-Heitler theory to predict the bremsstrahlung, agreement between experiment and theory of typically 10% is recorded. Finally, a means of simplifying the equations used to enable rapid calculation of x-ray spectra with a pocket calculator is indicated.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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