The upgraded IPNS single crystal diffractometer

The IPNS single crystal diffractometer (SCD) has been operating since 1981 primarily as a general purpose instrument for small molecule crystallography and for surveying reciprocal space. The instrument has recently undergone a major upgrade involving replacement of most of the hardware and software. In particular, two new position-sensitive scintillator area detectors based on the Anger camera concept were designed, fabricated and installed on the SCD. Each of these detectors have active areas of 15×15 cm² with a spatial resolution of better than 2 mm. A new data acquisition system permits the use of larger data files with a larger wavelength bandwidth at higher time-of-flight resolution. Software developed with tools in the ISAW workbench provides graphical manipulation of three-dimensional arrays of data in histogram coordinates and in reciprocal space, and user-friendly wizards for routine data analysis. As described in this paper, the upgrade of the SCD provides significant improvements in resolution, speed of data collection, and ease of use.