Diffraction measurements from crystals under electric fields: instrumentation

Based on the ideas of previous work, a device has been built for applying strong electric fields to a crystal during the measurement of diffracted intensities using a field-switching technique. It consists of a high-voltage supply, the electronics for switching the field, and synchronous counting on four chains combined with controls for step-scanning the diffraction profiles. By using this `stroboscopic' technique, it is possible to measure very small changes in Bragg angles arising from the strain induced by the converse piezoelectric effect, and also to measure minute changes in the Bragg intensities arising from polarizations of atomic structure and electron density.