Two-dimensional resolved maps of the q space were derived from the CCD images via data treatment that includes (1) positioning of the beam center, (2) polarization correction, (3) elimination of dead pixels, and (4) scaling. Data treatment was performed by applying a self-written MATLAB (The MathWorks, Natick, MA, USA) tool (Weinhausen 2010) . This tool further allows for sectioning through the reciprocal space at a definite angle (/) between q z and q k leading to extraction of the intensity courses along these sections via averaging over an angular ROI five pixels wide. The respective intensity profiles were linearized. Lorentzians with linear backgrounds were fitted to the extracted functions: