Enabling high-precision nano-positioning for beamlines: the Precision Metrology Lab at Diamond Light Source

The Precision Metrology Laboratory (PML) at Diamond Light Source provides an ultra-stable environment and specialist instrumentation to perform micro- and nano-scale dimensional metrology to support beamline operation. The lab enclosure is actively stabilised to 10 mK RMS in temperature and 0.5 %RH RMS in humidity. Under these conditions, sub-nm displacements have been measured using capacitive sensor and linear interferometers, and sub-nrad angles have been measured using autocollimator and angle interferometers$*$. Such measurement capabilities are required to characterise and enhance the performance of positioning systems for sample, optics, and detectors on the beamlines. This philosophy has frequently helped to identify faults prior to installation, including misalignments, parasitic motion errors, and controller issues, thereby saving a significant amount of X-ray commissioning time. Increasingly, the PML is involved in the prototyping of new beamline components that are beyond the production limits of commercial suppliers. Metrology data is routinely used to guide Engineering design decisions, following the mechatronics principle.