CALIBRATION AND APPLICATION OF AN X-RAY IMAGE INTENSIFIER CHARGE-COUPLED DEVICE DETECTOR FOR MONOCHROMATIC MACROMOLECULAR CRYSTALLOGRAPHY/

Charge-coupled device (CCD)-based X-ray detectors allow data to be col lected much more quickly (similar to 10 times) than with current on-li ne imaging-plate systems. At the ESRF, X-ray image intensifier/CCD det ector systems have been developed. These have great potential as fast read-out detectors for macromolecular and other forms of crystallograp hy. They are relatively large sensitive X-ray detectors but have two i nherent weaknesses: convex detection surfaces leading to spatial disto rtion and non-uniformity of intensity response, and susceptibility to small changes in magnetic fields. A large improvement has been made to the accuracy obtained by non-uniformity of response calibration and c orrection, using fluorescence from doped lithium borate glasses. Monoc hromatic macromolecular crystallography demonstration experiments with external user groups have shown that high-quality results may be obta ined under real experimental conditions.