Instrumentation in X-ray crystallography: Past, present and future

Abstract

This paper deals with the very great changes in X–ray crystallographic techniques and apparatus over a period of approximately the last 60 years. This is not a general history; it is a personal account of the developments with which I have been directly involved; it is, therefore, biased towards apparatus developments in the field of macromolecular crystallography in which I have worked during most of this period. The bias needs little excuse: many of the new techniques of X–ray crystallography were devised initially for large–molecule structure determinations which had most need of such advances in order to be feasible at all. Among them are the uses of computers in calculating electron density maps, the construction of automatic diffractometers and microdensitometers, the introduction of rotating-anode X–ray generators and of microfocus X–ray tubes, the development of electronic X–ray area detectors, the pioneering work on the use of synchrotron radiation for diffraction studies, the building of three–dimensional atomic models by computer and the complete automation of the mounting, selection and alignment of crystals on the diffractometer.