Characterization of the geometry of an array of CCD pixel detectors

The pixel distance as well as the relative orientation of an array of 6 CCD pixel detector chips have been determined with accuracies of about 1 nm and 50 μrad, respectively. This accuracy satisfies the needs of modern crystal spectroscopy experiments in the field of exotic atoms. Two different measurements have been attempted by illuminating masks in front of the detector array by a remote source of radiation. In one case an aluminum mask was irradiated with x-rays and in a second attempt a nanometric quartz wafer was illuminated by a light bulb. Both methods gave consistent results with a smaller error for the optical method. Furthermore, the thermal expansion with temperature of the CCDs could be determined. (author)