The width of the beam spread on the detector decreases with the increase of the ai. Similar to Figure , in Figure ,b we see areas corresponding to the reflection from the covered and non-covered parts of the surface, movement, and growth of graphene crystals. Each point on the map in Figure ,b corresponds to a specific scattering vector. The yellow marker highlights the area around qz = 0.8 Å -1 . After assigning each pixel of these 2D images to the correct qz values, the conventional 1D XRR curves can be reconstructed with the points belonging either to the XRR of the bare liquid copper or the XRR of the surface covered with graphene (Figure ). For clarity, we consider only the central part of the beam with the highest intensity (the half of the FWHM) during the reconstruction to minimize any parasitic scattering. The splitting is more pronounced in the case of the smaller flakes (red curve), while in the case of the green curve, a flake larger than the footprint covers the surface under the beam as the scan passes through the Kiessig minimum (Figure and).