Error analysis model-driven workflow for self-calibration stitching testing of X-ray flat surfaces

Self-calibration stitching test is widely utilized for testing X-ray flat surfaces. Various factors, including environment disturbances, motion errors, misalignments, overlapping ratios, and sub-aperture sizes can affect the accuracy. Previous studies have shown that motion errors can introduce slope errors in the test surface, and higher overlapping ratios can increase the test error. However, these error analyses have not been comprehensive or quantitatively sufficient for practical applications. For X-ray flat surfaces with specific accuracy requirements, the necessary control levels for error sources and the optimal test parameters remain unclear. To this end, an error analysis model-driven workflow for self-calibration stitching testing of X-ray flat surfaces is proposed. This model allows for the systematic evaluation of how different error sources and test parameters affect test accuracy. Further, it can guide the determination of the control levels of error sources and test parameters, moving beyond the reliance on empirical experience as seen in previous studies. A flat X-ray mirror with clear aperture of 250 mm × 30 mm and 0.2 nm (50 nrad) RMS accuracy requirement was utilized to demonstrate the procedures of the workflow. Verification experiments demonstrated that this workflow can serve as a standard model for evaluating test accuracy and guiding test procedures to achieve the desired accuracy in self-calibration stitching of X-ray flat mirrors.