Solving self-absorption in fluorescence

Abstract

One of the most common types of experiment in X-ray absorption spectroscopy (XAS) measures the secondary inelastically scattered fluorescence photon. This widespread approach has a dominant systematic of self-absorption of the fluorescence photon. The large impact of self-absorption compromises accuracy, analysis and insight. Presented here is a detailed self-consistent method to correct for self-absorption and attenuation in fluorescence X-ray measurements. This method and the resulting software package can be applied to any fluorescence data, for XAS or any other experimental approach detecting fluorescence or inelastically scattered radiation, leading to a general solution applicable to a wide range of experimental investigations. The high intrinsic accuracy of the processed data allows these features to be well modelled and yields deeper potential insight.

The New Paradox of Dual Modality X-Ray Diamond Sorting

“…In luminescence, the emitted X-ray intensity from a sample is presented in (10). In the transmission mode, the intensity of X-rays transmitted through the sample is as presented in (11). On the other hand, the transmission mode has been shown to perform best for large or concentrated samples while it experiences poor contrast for thin and dilutes samples [29].…”

Optimization of Data Processing Minimizes Impact of Self-Absorption on Phosphorus Speciation Results by P K-Edge XANES

“…Recent advances in self-absorption correction theory claim that it is now possible to correct self-absorption effects without extra measurements [10]. However, such algorithms have not yet been implemented in common software packages for spectral processing like Athena, Larch, or LCF, and thus we did not test them.…”

“…where ∈ is the fluorescence efficiency, ∆Ω is the solid angle of the detector, E f is the energy of the fluorescent x-ray, θ is the incident angle (between incident x-ray and sample surface), ϕ is the exit angle (between fluoresced x-ray and sample surface), µ x (E) is the absorption from the element of interest, and µ tot (E) is the total absorption in the sample. The total absorption [µ tot (E)] is the sum of the absorption of the element of interest [µ x (E)] and the absorption by other elements in the matrix [µ other (E)] [8,10]. Previous studies on self-absorption have developed mathematical algorithms and solutions aiming to correct the fluorescence yield distortions based mostly on Equation (2).…”

“…Previous studies on self-absorption have developed mathematical algorithms and solutions aiming to correct the fluorescence yield distortions based mostly on Equation (2). Yet, most of these approaches rely on knowledge of sample stoichiometry, measurements of multiple angles, or exact knowledge of the energy dependence of the absorption coefficients [10][11][12][13]. These conditions are hard to meet in environmental samples, thus it is recommended to avoid self-absorption effects rather than attempting to correct them [14].…”

High-accuracy measurement of mass attenuation coefficients and the imaginary component of the atomic form factor of zinc from 8.51 keV to 11.59 keV, and X-ray absorption fine structure with investigation of zinc theory and nanostructure

“…Thus, X-ray mass attenuation coefficients, particularly across absorption edge regions, are widely used in many techniques and fields including biological (Coulthard & Sham, 1996;Streltsov et al, 2018), molecular, condensed matter and solid state fields (Palmberg & Rhodin, 1968;Bohic et al, 2001) to study structural parameters including bond lengths, thermal parameters, oxidation number, coordination number and electron inelastic mean free paths of materials and molecules (Ignatov et al, 2001;Han et al, 2002;Islam et al, 2015Islam et al, , 2016. Attenuation coefficients and atomic form factors are important in the study of the ISSN 1600-5775 density of electron states (Joly et al, 1999;Hossain et al, 2005), roughness of sample surfaces (Glover et al, 2009), dynamics of atomic processes, elastic scattering and other scattering of X-ray interactions with matter (Hopersky et al, 2004) and self-absorption of materials (Trevorah et al, 2019). Mass attenuation across the XAFS can be used to confirm or determine near-neighbour coordination lengths of materials (Sayers et al, 1972;Glover et al, 2010).…”