A NOVEL LARGE AREA CCD DETECTOR FOR FOUR-CIRCLE DIFFRACTOMETERS. Kucharczyk, D., Meyer, M., Paciorek W.A. And Chapuis, G., Kuma Diffraction, Al. Akacjowa 15b, PL-53-122 Wroclaw, Poland, Universit de Lausanne, Institut de Cristallographie, BSP, CH-1015 Lausanne Switzerland

A novel CCD detector for use with a four-circle Kappa-geometry diffractometer will be presented. The large input window of >90mm diameter allows simultaneous high-resolution sampling of a diffraction pattern of >45 degrees in 2[[theta]]. The input window is shaped as a secondary beam collimator to reduce the influence of air scattering. A special CCD optics design (fully vacuum isolated) simplifies and reduces the requirements for the cooling device. Most of the vital and sensitive electronics are build into the camera head to minimise noise and interference. Low noise digitalisation electronics allow true 20-bit digitalisation of the recorded image in short time. The newly designed hardware supports various binning (electronic and/or software addition of pixels) and windowing modes (predefined regions of interest). The combination of a 4-circle goniometer and a large area detector with free selection of windows and binnings will allow the optimisation of data collection strategy for small to medium sized structures. The data processing principles and first performance results of this detector system will be presented.