Fabrication and predicted performance of the Advanced X-ray Astrophysics Facility mirror ensemble
Abstract
The Advanced X-ray Astrophysics Facility (AXAF) mirrors represent the largest, most precise, grazing incidence optics every built. The eight cylindrical mirrors, 0.84 meters long, and ranging in diameter from 0.6 to 1.2 meters, have all been successfully fabricated. The optical surfaces were fabricated using a deterministic, computer controlled, approach. Modeling of the computer controlled process was employed to achieve desired figure levels in a minimum of polish/metrology cycles. Figure error corrections of 80 to over 90 percent per cycle were routinely achieved. Final full-bandwidth figure levels ranged from about 180 angstroms rms to about 40 angstroms rms. Surface roughness values range from about 3.5 to less than 2 angstroms, rms, over a bandwidth of 1 to 1000 mm-1. Numerous metrology cross-checks give good confidence in the data. The fabrication, modeling, and metrology are described. Results of figure correction are presented. We also present an estimate for the predicted performance of the eight mirror ensemble and compare that with program requirements and goals.
- Publication:
-
X-Ray and Extreme Ultraviolet Optics
- Pub Date:
- June 1995
- DOI:
- 10.1117/12.212602
- Bibcode:
- 1995SPIE.2515..361R