HIGH-FREQUENCY ELECTROACOUSTIC CHOPPER FOR SYNCHROTRON-RADIATION

The grazing incidence diffraction of an X-ray beam on surface acoustic waves (SAW) gives rise to diffraction satellites. A new high-frequenc y chopper for synchrotron radiation is presented here, based on this i nteraction. The temporal structure of the satellite intensities appear ing in the diffracted beam can be directly correlated to the temporal structure of the acoustic waves, By electronic pulsing of the SAW emis sion and synchronization with the arrival of the synchrotron X-ray pul ses, it is possible to select the X-ray flashes which will be diffract ed in the satellites. A selection of 20% of each single X-ray pulse an d an elimination of 99.7% of the unwanted ones in the hybrid mode of t he ESRF (repetition frequency similar to 350 kHz) has been achieved. ( C) 1997 Published by Elsevier Science B.V.