User-friendly interfaces for control of crystallographic experiments at CHESS

Abstract

In designing a system to collect high quality diffraction data in an efficient manner, both hardware and software must be considered. This work focuses on the data collection software used at CHESS, the Cornell High Energy Synchrotron source, with emphasis on the interface between the user and the experimental components. For each type of detector used at CHESS, there is a graphical user interface (GUI) enabling the user to easily set up and run an experiment. For the CCD detector from Area Detector Systems Corp., this is a commercial product from ADSC, customized for CHESS. For the Princeton CCD detectors, a GUI has recently been developed to streamline communication between the user and the TV6 program which controls the detector. For Fuji imaging plates, a new GUI controls operation of the oscillation camera, including the imaging plate carousel; scanning of plates is done using the software provided by Fuji. Although these GUI’s are not identical, they have numerous similarities, making it easier for users to learn operation of a new detector. They also incorporate error-checking to avoid problems such as overwriting data files or collecting data with no x-rays. Common to experiments with all detectors is a GUI used for operations such as alignment of the optical table on which the oscillation camera is mounted. Integral to a good data collection system is the capability to process diffraction images, for evaluation of crystal quality, determination of data collection strategy, screening of potential derivatives, and so forth. The mccview graphical front-end has been developed to conveniently initiate processing programs, including preliminary routines (correct, getbeam), main analysis routines (xdisp, denzo, scalepack), and the strategy routine m.simulate.