Fig. 132: The single-crystal Laue-interferometer has three thin wafers, cut for Si-220 reflection. The X-ray beam is split by the first wafer, recombined by the second, and the third wafer analyses the resulting interference pattern. The very precise translation of the analyser wafer is achieved by a weak link and a force produced by a solenoid acting on a permanent magnet which is glued to the interferometer.