Matrix-free integration of image-plate diffraction data

Matrix-free integration of area-detector diffraction data is developed to interpret data collections from single crystals, twinned or multi-phased crystals as well as quasicrystals. A pixel-background method based on the algorithm described by Bolotovsky, White, Darovsky & Coppens [J. Appl. Cryst. (1995), 28, 86-95] is employed. The method is modified by using an azimuthal coordinate system and distinguishes reliably between significant scattering intensities and background intensities. Very broad intensity distributions from e.g. powder rings can be determined and reflections superimposed by diffuse scattering can be integrated reliably. A complete program suite to process area-detector data, both from image-plate and CCD detectors, is presented. The program uses both matrix-free as well as matrix-based integration. The program is tested on single-crystal and twinned-crystal diffraction data.