Quality-assurance demands and realization for thin-walled mirror blanks made of ZERODUR for the AXAF project
The Advanced X-ray Astrophysics Facility (AXAF) will be a space-based observatory consisting of special mirrors to form images in x rays. The mirrors are composed by nested conical shaped thin walled ZERODUR cylinders. ZERODUR is the ideal material for grazing incidence optics. The production steps of these ZERODUR blanks are briefly described. Different QA techniques, detection of tiny inclusions in the glass ceramic via infrared light, precise dilatometer measurements of the coefficient of thermal expansion and specific optical metrology, had to be applied. Results of the metrology are discussed.