Crystal orientation and X-ray pattern prediction routines for area-detector diffractometer systems in macromolecular crystallography

Abstract

Routines for crystal orientation and the prediction of expected reflections which are part of the data collection software package MADNES for area-detector diffractometer systems in macromolecular crystallography are described. This package is designed to be area-detector-system independent. In addition to refining crystal cell lengths and angles, crystal orientation, crystal-to-detector distance, position of the primary beam on the detector, and rotation of the detector around the primary beam, the orientation routine also refines the effective mosaic spread of the crystal, the beam inclination angle μand the detector tilt angle τ. A prealignment procedure is described for rapid rough orientation of the crystal. The routines are written in Fortran 77 in a modular way, so that they may be used independently of MADNES and each other.