Fig. 66: The Si (111) single crystal, linear phase Bragg-Fresnel lens (BFL), and the sample were arranged in a double crystal diffractometer mode, as shown schematically. The BFL was used both to monochromatise the synchrotron radiation and to focus the X-ray beam. The BFL with a focusing distance of 0.6 m was adjusted for the energy of 18 keV, determined by the absorption edge of Zr. With a slit system, a spot of 2 µm height and 30 µm length, was adjusted for the experiments in the present case. The sample-to-detector distance was selected to be 0.82 m, in order to have sufficiently high angular resolution for the line profile measurements. A linear position sensitive proportional counter with a spatial resolution of about 80 µm was used for the measurements of the line profiles of the (400) and/or (004) Bragg reflections. The samples were mounted on a high precision goniometer with an x-y-z three-dimensional translation stage.