From then till now: changing data collection methods in single crystal X-ray crystallography since 1912

ABSTRACT The principal method used today for single crystal X-ray data collection is the Arndt–Wonacott screenless rotation method formalized in the late 1970s, but the physical hardware used now would be barely recognizable to scientists at that time. However, the technique of rotating a crystal around a single goniostat axis, illuminating it with monochromatic radiation, and collecting the data on a flat detector is identical. Indeed, this would not have been very surprising to the pioneers of X-ray crystallography early in the Twentieth Century, since the elements of this method were available in the early days of the science. In a sense, therefore, we have come full circle after utilizing a variety of different experimental methods and equipment, and the question arises; ‘how did we get here?’; after all, there were long periods in our science where we used point detectors or curved area detectors, or using polychromatic X-rays and stationary crystals. This review was originally presented at ECM31 in Oviedo, Spain in August 2018 under the title `Vagando entre los picos ¿cómo llegué hastaaquí? Improving methods in data collection and processing’; the Spanish texttranslates as ‘Wandering amongst the peaks – how did I get here?’.