Second metrology round-robin of APS, ESRF and SPring-8 laboratories of elliptical and spherical hard-x-ray mirrors

The first series of metrology round-robin measurements carried out in 2005 at the APS, ESRF and SPring-8 metrology laboratories involving two flat x-ray mirrors and a cylindrical x-ray mirror has shown excellent agreement among the three facilities' Long Trace Profilers (LTP) despite their architectural differences. Because of the growing interest in diffraction-limited hard x-ray K-B focusing mirrors, it was decided to extend the round robin measurements to spherical and aspheric x-ray mirrors. The strong surface slope variation of these mirrors presents a real challenge to LTP. As a result, new LTP measurement protocol has to be developed and implemented to ensure measurement accuracy and consistency. In this paper, different measurement techniques and procedures will be described, the results will be discussed, and comparison will be extended to micro-stitching interferometry measurements performed at Osaka University, Japan.