Voigt profile characterization of copperKα

Abstract

We report a characterization of the Cu Kα profile and a transferable determination of the 2p satellite line using a new Voigt methodology which generates improved fits, smaller residuals and details of Compton profile features. The Kα 1,2 emission of Cu was obtained from a rotating anode through a monolithic Si channel-cut monochromator. Least-squares fitting of a minimum set of Voigt profiles reached a noise limit. Sufficient statistical information and resolution permits the determination of major and minor peak components in a fully-free least-squares analysis rather than the previous constrained single peak-by-peak method. Relative energies of the component Voigts within each profile, linewidths and Kα 1 /Kα 2 peak intensity ratios, are compared to the previous best empirical sum of Lorentzian-slit peaks, clearly demonstrating that a sum of Voigt profiles provides a superior fit to the observed profile. 104 profiles at accelerating voltages from 20 kV through 50 kV provided a stable unique profile across the broad range of 2.5−6.25 times the characteristic energy. This robustness proves the stability of Cu Kα for use in high accuracy calibration, and supports the validity of the impulse approximation across this range of energy. The lineshape, contributions to noise broadening, the quantum yield and the Fano factor, relevant to spectral profiling, are discussed.

Strain-induced perpendicular magnetic anisotropy and Gilbert damping of Tm3Fe5O12 thin films

“…Figure 1 shows XRD θ –2 θ scans measured for all samples around the sGGG (444) reflection. The diffraction pattern of a bare substrate is displayed for comparison, revealing a splitting of the main (444) reflection due to contributions from the Cu Kα 1 , Cu Kα 2 , and Cu Kα 3,4 radiations 28,29 , which are sometimes misinterpreted in the literature 30 .

Figure 1XRD θ –2 θ scans of the (444) and (4–44) planes of TmIG/sGGG(111) samples for various film thicknesses and of a bare substrate. The position of bulk TmIG (444) reflection is marked with a vertical line.

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MCDF-RCI predictions for structure and width ofKα1,2x-ray line of Al and Si

“…For asymmetric x-ray peaks, for example a Kα 1,2 or Kβ 1,3 lines for low-and medium-Z elements, the best way, characterized by a small χ 2 r coefficient, is to fit a measured spectrum with a couple of Voigt profiles (or just Lorenzian profiles, if instrumental broadening, given as a Gaussian width, is small). This way is established from many years in fitting of experimental spectra of 3p-elements [26,29] and 3d-elements [10,[30][31][32][33][34]. The higher number of Voigt/Lorenzian profiles used, the better fitting and the smaller χ 2 r coefficient obtained [34].…”

“…This way is established from many years in fitting of experimental spectra of 3p-elements [26,29] and 3d-elements [10,[30][31][32][33][34]. The higher number of Voigt/Lorenzian profiles used, the better fitting and the smaller χ 2 r coefficient obtained [34]. However, the higher number of profiles used in fitting an experimental spectrum, the bigger the interpretation problems.…”

Count‐rate, linearity, and performance of new backgammon detector technology

“…The detector was set to a voltage of 2,100 V, using P10 (90% argon and 10% methane) as the ionising gas. Multiple profiles of the Cu K α spectrum were taken with exposure times of 7,200 s. The rotating anode voltage was set to 20 kV, where the K α spectrum has been shown to be stable . A highly attenuated background exposure was also taken, only allowing residual high energy X‐rays to reach the detector face, to separate fundamental and higher order scattered radiation (Appendix D).…”