Determination of binary systems based on light elements by the ratio of the Compton and Rayleigh scattering intensities

Abstract

A generalization of the Compton method for determining elements with a low atomic number Z from 1 (H) to 9 (F) by the ratio trueICIR of the intensities of incoherent (Compton) and coherent (Rayleigh) scattering is proposed. The generalization takes into account not only the dependence of this ratio on the effective atomic number of the scatterer material but also the momentum transfer variable x = sin0.5emθλ. The new method is based on the application of calibration function of trueICIR=g()Z,x obtained by measuring scattering spectra at two values of x1= 0.831 Å−1 and x2= 1.297 Å−1 with a WDXRF spectrometer. The elemental atomic numbers and their concentrations of binary compounds with unknown compositions are determined by the solution of a system of linear equations. Coefficients of the equations are calculated from the measured trueICIR ratios for the test sample and the regularization solution for the corresponding calibration. The experiments have been carried out for standard samples of single‐component, binary and triple stoichiometric compounds based on H, Li, Be, B, C, O and F. The identification of these elements was found to be possible in the absence of a relationship between the positions of scattering peaks and the composition of the sample, and a qualitative and quantitative analysis of the composition of the material was carried out as part of the solution of a single inverse problem.

Analytical performance of Compton/Rayleigh signal ratio by total reflection X‐ray fluorescence (TXRF): A potential methodological tool for sample differentiation

“…In consequence, the ratio between Compton and Rayleigh bands can be used to assess the total chemical composition of a sample through the determination of its Z eff. 11–18 For samples with known elemental composition, Z eff can be calculated theoretically by different mathematical methods 19,20 . However, for complex matrices, Z eff is typically calculated through a calibration curve, built on reference materials with known elemental composition.…”

“…However, for complex matrices, Z eff is typically calculated through a calibration curve, built on reference materials with known elemental composition. This kind of approach enables to determine the experimental Z eff of a sample of interest based on its Compton/Rayleigh or Rayleigh/Compton signal ratio, and has been applied to characterize and differentiate both simple and complex matrices, such as single‐component and binary materials of stoichiometric composition, 13,14 triple stoichiometric compounds, 14 glassy carbon, 15 plastics, 15 topaz crystals, 15 ivory jewelry and decorative objects, 16 human teeth, 16 vegetable oils, 17 and human breast tissue 18 . In the cited studies, both the Compton/Rayleigh 13–16 and the Rayleigh/Compton 17,18 signal ratios have been used.…”

“…This kind of approach enables to determine the experimental Z eff of a sample of interest based on its Compton/Rayleigh or Rayleigh/Compton signal ratio, and has been applied to characterize and differentiate both simple and complex matrices, such as single‐component and binary materials of stoichiometric composition, 13,14 triple stoichiometric compounds, 14 glassy carbon, 15 plastics, 15 topaz crystals, 15 ivory jewelry and decorative objects, 16 human teeth, 16 vegetable oils, 17 and human breast tissue 18 . In the cited studies, both the Compton/Rayleigh 13–16 and the Rayleigh/Compton 17,18 signal ratios have been used. Since the Compton band typically has a higher integrated intensity than the Rayleigh band, the Compton/Rayleigh ratio has a larger magnitude than the Rayleigh/Compton ratio.…”

“…Then, the former is associated with a higher sensitivity than the latter. In addition, some authors have built their calibration curves with the Z eff of pure elements 17,18 and others employed the Z eff of compounded standard materials 13–16 . Notably, while both EDXRF 15–18 and WDXRF 13,14 have been used in this context, TXRF has not.…”

“…In addition, some authors have built their calibration curves with the Z eff of pure elements 17,18 and others employed the Z eff of compounded standard materials 13–16 . Notably, while both EDXRF 15–18 and WDXRF 13,14 have been used in this context, TXRF has not. Moreover, the effect of the X‐ray method setup, including sample preparation, X‐ray excitation source selection, and band deconvolution procedure, has not been assessed in this kind of approach.…”