Intensity map at different positions on the Ge (004) reflection. (a) Radial scan across the Ge and Si (004) reflections recorded at position 3 displayed in Fig. 1(b). (b) Detail around the Ge (004) reflection. (c)–(e) Meshes recorded at different Bragg angles as indicated in (b). Note: the peak shape is a result of the convolution with the hollow-cone-shaped primary beam caused by the FZP.