Slope error evaluation method for interferometric test results of X-ray mirrors.

Area of Science:

• Optics and Optical Engineering
• Metrology
• Materials Science

Background:

• Accurate slope error evaluation is critical for X-ray mirror fabrication.
• Comparing interferometers and slope profilers requires standardized methods.
• Existing methods lack consistency in assessing mirror surface accuracy.

Purpose of the Study:

• To develop a standardized model for evaluating X-ray mirror slope error.
• To analyze the impact of point spread function (PSF) and sampling on form measurements.
• To enable consistent comparisons between interferometric and profiler measurements.

Main Methods:

• Established a slope error evaluation model based on the ISO Gaussian filter.
• Determined cut-off wavelength using interferometer and profiler Instrument Transfer Functions (ITFs).
• Defined truncation constant based on the profiler's spot intensity distribution.

Main Results:

• Successfully transformed stitched height error data into slope errors.
• Verified the model by comparing results from interferometers and Linear Profilometers (LTPs).
• Demonstrated consistency between different measurement systems.

Conclusions:

• The developed model provides a standardized procedure for slope error evaluation.
• The model aligns with ISO standards for Gaussian filtering and ITF calibration.
• Promotes consistency in X-ray mirror manufacturing and advanced light source applications.