High-frequency modulation of an X-ray beam by diffraction on surface acoustic waves. Application to the design of a MHz range chopper and to digital data transfer by X-rays

The diffraction of an X-fay beam on an ultrasonic wave propagating at the surface of a crystal gives rise to diffraction satellites whose temporal structure is correlated to the one of the ultrasonic wave, Two different applications of this phenomenon are presented in this paper: By matching the temporal structure of the surface acoustic wave (SAW) with the filling mode of the storage ring, it is possible to pick or reject the incident X-ray pulses and thus to built a chopper working in the MHz range. The second application deals with binary data transfer by an X-ray beam. The experiment consists in modulating the signal fed to the acoustic transducer with a signal carrying digital data, which is a way of transmitting this information into the X-ray beam satellite.