Electric-field-induced structural changes measured with a CCD-coupled X-ray image intensifier

The conventional method to measure small induced changes in integrated inte nsity utilizes a zero-dimensional detector, which greatly limits the data c ollection speed. This paper shows that the use of an area detector in combi nation with an X-ray chopper decreases the data collection time significant ly. A monochromatic diffraction setup using a charge-coupled device (CCD) d etector coupled to an X-ray image intensifier was constructed and tested. T he setup proved to be sufficiently stable to measure changes in integrated intensity well below 0.1%. Subsequently, a data set of a piezoelectric KD2P O4 crystal in an external electric field was collected. The data were merge d to yield 77 unique reflections. The induced structural changes were deter mined by a least-squares refinement. The results agree very well with exper iments in which a zero-dimensional detector was used. The major improvement is the decrease in data collection time by one order of magnitude, without any degradation of the data quality, offering new possibilities for this t ype of perturbation study.