Low-temperature raster system for moving crystals with application to sound-beam topography

Abstract

Construction details of a low-temperature raster system for moving crystals with a maximum size of 14 mm × 14 mm × 14 mm over a small area of piezoelectric sound excitation are described. The pure mechanical raster system in the liquid helium is driven by two stepping motors outside the cryostat. The minimum step size is 1 μm and the maximum raster area 14 mm×14 mm. This raster system was used in sound-beam topography at a frequency of 70 GHz. For this purpose, a special quasioptical transmission line across the dewar wall was also developed which is briefly described together with the applied electromechanical transducer system.