Microfocus and variable beam size at the Diamond Light Source I04 beamline

Abstract Beamline I04 has been in operation at Diamond Light Source since 2007. It was conceived as a standard layout macromolecular crystallography (MX) instrument using a commercial Double Crystal Monochromator (DCM) and Kirkpatrick-Baez (KB) mirror focus when the beamline came into operation. However, the beamline has been under constant development over the years to become a flexible, easy-to-use, variable focus beamline. In addition to upgraded components and diagnostics in the current layout, the key difference is the use of Compound Refractive Lenses (CRL) focus instead of the already installed KB mirrors. The lens-based optics enables a unique combination of features and capabilities that are difficult or impossible to achieve with KB mirrors.