Corrections for surface X‐ray diffraction measurements using the Z ‐axis geometry: finite size effects in direct and reciprocal space

X‐ray diffraction data have to be corrected by geometrical correction factors prior to any quantitative analysis. Here the case of grazing incidence X‐ray diffraction measurements is considered, including the case of high exit angles. First, an approach taking into account the evolution of the diffracting area during an ω scan is presented. From the calculation of the effective part of the sample surface that participates in the diffraction phenomena at each step of the scan, a more accurate correction factor than those commonly used is derived and the evolution of the line shape along a zero‐width rod is explained. Secondly, the case of finite‐width rods, under the point‐like sample approximation, is considered: the influence of the partial integration, as a result of the detector in‐plane acceptance, of a rod with an anisotropic in‐plane shape, is studied and leads to an analytical expression for the corresponding correction factor. Finally, a full numerical simulation is presented, which provides an alternative method for correcting the experimental intensities and shows in which conditions the previous formulae are no longer valid.