Development on single field of view relative angle determinable stitching interferometry (RADSI) at NSLS-II

As scientific experiments at synchrotron radiation facilities continue to advance, X-ray mirrors are required to meet more complex shapes and stringent specifications, such as larger total slope ranges and shorter radii of curvature, while maintaining tight tolerances. As a result, accurate metrology of X-ray mirrors has become essential to ensure their precise fabrication and performance in beamline experiments, posing a significant challenge for measurement techniques and methods. We present our Single Field of View (SFOV) Relative Angle Determinable Stitching Interferometry (RADSI) system, developed at the National Synchrotron Light Source II (NSLS-II). In this research, we revisited the RADSI principle for measuring curved X-ray mirrors and designed a parallel flexure-based metrology platform to enhance measurement accuracy. We also calibrated the Fizeau interferometer, evaluated the angular stability of the system, and tested the performance of the newly developed SFOV RADSI metrology instrument.