A NEW SYNCHROTRON-BASED DIFFRACTION TECHNIQUE FOR PERTURBATION CRYSTALLOGRAPHY

A new diffraction technique based on a wide-energy-bandpass X-ray beam in connection with lock-in detection for diffraction studies of cryst als subjected to external perturbations has been developed. The broad- energy-bandpass beam is obtained by combining a wiggler or bending-mag net source with a curved Si monochromator in Laue geometry. This new t echnique has been applied in diffraction experiments on single crystal s in external electric fields. Both the speed and accuracy of the meas urements are increased by more than two orders of magnitude compared w ith conventional methods.