Fabrication, performance, and figure metrology of epoxy-replicated aluminum foils for hard x-ray focusing multilayer-coated segmented conical optics

We fabricated x-ray mirrors for hard x-ray (greater than or equal to 10 keV) telescopes using multilayer coatings and an improved epoxy-replicated aluminum foil (ERAF) nonvacuum technology. The ERAF optics have similar to1 arcmin axial figure half-power diameter (HPD) and passed environmental testing.

Reflectivity measurements at 8 keV on ERAFs with and without multilayer coatings show a 4.4 to 4.8 A root mean square (rms) microroughness for correlation lengths less than or equal to 15 mum. To reduce the dominant contribution of mirror assembly and large-scale distortion in the overall telescope HPD, we designed a figure metrology system and a new mounting technique.

We describe a cylindrical metrology system built for fast axial and roundness figure measurement of hard x-ray conical optics. These developments lower cost and improve the optics performance of the HEFT (high-energy focusing telescope) and Constellation-X missions.