Corrections for scattering in X‐ray fluorescence experiments

Keith, H. D.; Loomis, T. C.

doi:10.1002/xrs.1300070410

Cited by 28 publications

(12 citation statements)

References 8 publications

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“…Assumption (i) is an approximation but it nevertheless has sufficient validity as to have appeared to be substantiated within small limits of error in early experiments performed to test itlo (also see fuller discussion of this point in Ref. 9). As for assumption (ii), we would not expect the particular choice of smooth angular distribution function to be of prime importance.…”

Section: Corrections For X-ray Scatteringmentioning

confidence: 91%

Measurement of K‐shell flourescence yield and Kα/Kβ intensity ratio for nickel

Keith¹,

Loomis²

1978

X-Ray Spectrometry

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For application of the fundamental parameter approach to quantitative chemical analysis of mixtures by X-ray fluorescence, accurate knowledge is required of fluorescence yields and relative intensities of X-ray lines of the various elements involved. The spread in published data suggests, however, that these parameters are not known with as much accuracy as could be used profitably. In this paper we describe a method by which K-shell fluorescence yield and Ka/KP intensity ratio can both be measured in the same experiment to within approximately 0.5 % for pure elements available as thin polycrystalline foil. Results are given for the particular case of nickel (Z = 28) for which we find WK = 0.452 k 0.002 and Ka/KP = 6.91 k 0.035, but the method is readily applicable to any element whose atomic number falls in the approximate range 20 5 2 5 50 and which can be obtained in suitable physical form. A key factor in the experimental design is use of a non-dispersive (intrinsic germanium) X-ray analyzer; this makes it possible to employ a very simple transmission geometry which can be characterized quite precisely. Experimental conditions, and precautions needed to obtain accurate and consistent results, are described in some detail. Among other corrections applied, allowance is made for scattering of both exciting and fluorescent radiation within the sample. The limiting sources of error appear to be counting statistics and residual uncertainties in calculating corrections for scattering. Among these residual uncertainties are errors in correcting scattering coefficients for anomalous dispersion. Such errors are significant only when evaluating f~, the K-shell excitation efficiency; the important product ~K U K can, however, be determined (~K W K = 0.398 f 0.002) with greater reliability than OK itself.

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Section: Corrections For X-ray Scatteringmentioning

confidence: 91%

Measurement of K‐shell flourescence yield and Kα/Kβ intensity ratio for nickel

Keith¹,

Loomis²

1978

X-Ray Spectrometry

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“…Again, a least-squares fit was made when a second-order fit was used for the contribution from characteristic radiation and a fifth-order fit for the contribution from bremsstrahlung and the sum of both. (20) sc (21) Ti (22) v (23) Cr (24) Mn (25) Fe (26) Co (27) Ni ( (3b) In the XRF experiment, each time the mean value of 15 measurements was taken, which gave the results listed in Table 3 for the Ka peaks of the four standards.…”

Section: Sensitivity Factorsmentioning

confidence: 99%

Measurement of the spectral distribution of a diffraction x‐ray tube with a solid‐state detector

et al. 1992

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A knowledge of the spectral distribution method emitted by an x-ray tube is important for all calculations in quantitative x-ray fluorescence analysis. A simple way of directly measuring the primary spectrum of an x-ray tube with a solid-state detector is presented. For samples which meet thin-film criteria sensitivity factors based on the measured primary spectrum were calculated and compared with experimental values.

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“…Several workers have evaluated the effects of multiple scattering on the fluorescence intensity in different ways. Approximate theoretical expressions derived under various simplifying assumptions were proposed by Keith and Loomis 6 for calculating scattering contributions to measured intensities in x-ray fluorescence experiments. The principal approximations they made were physical; the authors assumed that the intensity of scattered photons can be adequately described by smooth angular functions.…”

Section: Introductionmentioning

confidence: 99%

“…In this paper, we present a theoretical formalism, more realistic than that of Keith and Loomis, 6 to calculate the contribution of scattering of photons both of the incident and of the outgoing beam to the x-ray fluorescence intensity. We compute all four second-order interactions involving one scattering process (elastic, Rayleigh; or inelastic, Compton) and one photoelectric absorption, for a monochromatic and unpolarized incident x-ray beam.…”

Section: Introductionmentioning

confidence: 99%

Contributions of double interaction processes to x‐ray fluorescence intensity

Tirao

Stutz

2003

X-Ray Spectrometry

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An algorithm for calculating the contribution of double x-ray interaction processes to the primary fluorescence emission is described. Four second-order processes including one scattering event (elastic or inelastic) and one photoelectric absorption were considered. Compton scattering events were more accurately described than in previous work by using a relativistic double-differential cross-section, which takes into account binding energy effects as well as momentum distribution of electrons of all atomic orbitals. Calculations of the contribution of double interaction processes were performed considering various experimental conditions (different sample thicknesses, atomic numbers, incident and outgoing angles and incident photon energies). The results show that for energies ranging from a few tens of keV up to 120 keV scattering contributions to the Ka 1 fluorescence line vary from ∼1% to several tens of percent (exceeding 50% for light elements). The relative scattering contribution is a rapidly increasing function of the sample thickness and reaches a saturation regime at a thickness of the order of the mean free path of the photons. The saturation value depends on the photon energy. Considerable deviations from a previous theoretical formalism were found. This discrepancy must be attributed to a more realistic description of single scattering events included in the present formalism. The present results are in very good agreement with those calculated from the transport theory.

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Corrections for scattering in X‐ray fluorescence experiments

Cited by 28 publications

References 8 publications

Measurement of K‐shell flourescence yield and Kα/Kβ intensity ratio for nickel

Measurement of K‐shell flourescence yield and Kα/Kβ intensity ratio for nickel

Measurement of the spectral distribution of a diffraction x‐ray tube with a solid‐state detector

Contributions of double interaction processes to x‐ray fluorescence intensity

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