A computer-vision-based instrument for nanometer accuracy measurement of runout

Abstract The performance of experiments in a synchrotron beamline depends on the precision of the motion and positioning of multiple components. Motion errors like the runout of rotary stages are often too large for high spatial resolution experiments. In this work, we present a method to measure the runout of a rotary stage that does not use any reference surface and does not require any complex alignment. It achieves nanometre resolution of the displacements, high angular resolution and high accuracy, even for continuous motion. We describe the method and its application to optimise the high-resolution goniometer of the microfocus MX beamline XAIRA at ALBA.