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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. [ABSTRACT FROM AUTHOR]

Here, the novel technique of extended-range high-energy-resolution fluorescence detection (XR-HERFD) has successfully observed the n = 2 satellite in manganese to a high accuracy. The significance of the satellite signature presented is many hundreds of standard errors and well beyond typical discovery levels of three to six standard errors. This satellite is a sensitive indicator for all manganese-containing materials in condensed matter. The uncertainty in the measurements has been defined, which clearly observes multiple peaks and structure indicative of complex physical quantum-mechanical processes. Theoretical calculations of energy eigenvalues, shake-off probability and Auger rates are also presented, which explain the origin of the satellite from physical n = 2 shake-off processes. The evolution in the intensity of this satellite is measured relative to the full Kα spectrum of manganese to investigate satellite structure, and therefore many-body processes, as a function of incident energy. Results demonstrate that the many-body reduction factor S 0 2 should not be modelled with a constant value as is currently done. This work makes a significant contribution to the challenge of understanding many-body processes and interpreting HERFD or resonant inelastic X-ray scattering spectra in a quantitative manner., (open access.)