X-Ray Scattering and Fluorescence From Atoms and Molecules

Southworth, S. H.; Young, Linda; Kanter, E. P.; LeBrun, Thomas W.

doi:10.1142/9789812813473_0022

Cited by 4 publications

(3 citation statements)

References 56 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Elastic and inelastic scattering processes in atoms, gases and elemental solids remain major topics of current research and investigation [1]. Major experimental coincidence studies [2,3] provide valuable information about the relative magnitudes of individual processes and their relative angular dependence, but are difficult to perform and often appear to disagree with current theoretical predictions.…”

Section: Introductionmentioning

confidence: 99%

Absolute determination of the effect of scattering and fluorescence on x-ray attenuation measurements

Tran

Jonge

Barnea

et al. 2004

J. Phys. B: At. Mol. Opt. Phys.

View full text Add to dashboard Cite

We investigate the effect of x-ray scattering and fluorescence upon measurements of the x-ray mass attenuation coefficient. Measurements of scattering and fluorescence are obtained from a comparison of attenuation measurements using different sized apertures to admit varying amounts of the scattering and fluorescence into the detectors. The result of such a comparison is found to be in good agreement with a theoretical calculation of the fluorescent and scattered photons reaching the ion chambers and, under our experimental conditions, decreases the measured attenuation coefficients of silver by up to 0.2%.

show abstract

Section: Introductionmentioning

confidence: 99%

Absolute determination of the effect of scattering and fluorescence on x-ray attenuation measurements

Tran

Jonge

Barnea

et al. 2004

J. Phys. B: At. Mol. Opt. Phys.

View full text Add to dashboard Cite

show abstract

“…When X‐rays interact with a material, they are scattered elastically (coherent scattering and often labeled Rayleigh scattering for isolated scatterers) and inelastically (often labeled incoherent scattering and often dominated by Compton scattering) while X‐ray fluorescence (often labeled resonant inelastic X‐ray RIX[S] or resonant X‐ray emission RXE[S]) is also produced in the absorbing material. [ 11 ] X‐ray fluorescence is significant at and above the absorption energy, whereas the effects of Laue–Bragg scattering and thermal diffuse scattering are significant at specific energies, and Rayleigh scattering is generally a smooth function. Smooth inelastic scattering (non‐resonant) is observed below and above the absorption edge in the form of Compton, plasmonic, and optical molecular interactions [ 12,13 ] and is dipolar in nature to first order and hence primarily directed through a scattering angle of π/2; hence the impact on a transmission measurement as in this experiment serves primarily to reduce the transmitted intensity of the beam and becomes significant and dominant for high[er] energy X‐ray regions.…”

Section: Introductionmentioning

confidence: 99%

The significance of fluorescence in transmission X‐ray absorption spectroscopy and X‐ray absorption fine structure

2021

View full text Add to dashboard Cite

We present a method to explore the effect of fluorescence on X‐ray attenuation measurements obtained from X‐ray absorption spectroscopy (XAS). We use the X‐ray extended range technique‐like method (XERT‐like). The experimental setup includes different sized apertures to control the number of secondary X‐rays entering the detector. Comparison of attenuation measurements produced with different aperture combination permit investigation of the effect of fluorescence radiation. In this work, fluorescence has a large impact on the attenuation measurements of thick zinc foils. The correction is energy‐dependent and sample thickness‐dependent and changes the structure and relative amplitudes of oscillations in the near‐edge region. Correction for this systematic is important for absolute measurement, for edge‐jump and edge characterization, and for near‐edge structure and amplitudes. A significant background scattering due to zinc fluorescence from the beamline optics was identified and treated for the first time. The model theory fits the experimental measurements well. The resulting correction is most significant for thicker foils with the 50 μm sample experiencing a shift in attenuation of up to 15.5% for the largest aperture while the 25 and 10 μm samples saw corrections of up to 0.153 and 0.00639% respectively. The standard error from the dispersion and variance was reduced by up to 50.5% after the correction for the 50 μm sample. This enables high‐accuracy data and theoretical and experimental analysis to below 0.03% accuracy. The technology is advanced. There is a cost in preparation and measurement time of less than a factor of two, and the principles are clear and can be routinely implemented on any beamline. This paper focuses on the model and parameters for fluorescence.

show abstract

“…Our group has conducted several experiments on X-ray/atom interactions involving X-ray scattering, multiple ionization, vacancy-decay processes, and photoelectron angular distributions. Overviews of this work are given in Southworth et al (2000); Dunford et al (2003). While the high flux and brightness of thirdgeneration synchrotron light sources have enabled experiments with unprecedented detail, the peak power and coherence properties of existing X-ray sources do not approach those of optical lasers.…”

Section: Introductionmentioning

confidence: 99%