A new protein crystallography station on the SRS wiggler beamline for very rapid Laue and rapidly tunable monochromatic experiments: I. Design principles, ray tracing and heat calculations

Abstract

A new instrument is being established on the SRS wiggler beamline at Daresbury. The design consists of a toroid focussing mirror to produce a point focussed white beam of X radiation of an intensity sufficient for millisecond and sub-millisecond Laue exposures from protein crystals. The wavelength band available for focussed Laue experiments will be variable by means of a plane mirror with an adjustable graze angle and by adjustable thickness beryllium filters. Unfocussed white beam will also be available to provide the full spectral range of the wiggler source. New, larger film cassettes and changing mechanisms are being designed to use the available data more efficiently (by decreasing spatial overlap and increasing the number of recording ‘singlet’ reflections). A double crystal monochromator option will be available for rapidly tunable monochromatic data collection. Design principles based on theoretical work and ray-tracing are dealt with in the paper.