Pictures of the knife-edge probe aligned close to the exit of a two-dimensional waveguide. The images were recorded at different magnifications using the horizontally viewing video microscope (see Fig. 3) and the X-ray beam direction is from left to right. The stud through which the beam exits the waveguide protrudes about 100 µm from the waveguide face side and is a breaking edge caused by the waveguide fabrication process. The dotted line indicates the position of the waveguide channel in the silicon wafer (the actual waveguide channel runs within the silicon, i.e. is not visible in the images).