Fabrication of CVD-SiC thin shells for x-ray optic applications

CVD SILICON CARBIDE shells have been fabricated by a scalable chemical vapor deposition vapor deposition process to demonstrate the feasibility of producing thin, lightweight optics for x-ray applications. These shells were produced by depositing SiC on shaped graphite mandrels in a CVD chamber, removing the graphite mandrels from SiC deposit followed with controlled machining to produce the required double cone surface. the size of these shells is as follows: diameter equals 250-600 mm, length equals 240-400 mm and thickness equals 1.5-2.7 mm. The roundness of the inside surface of these shells was the inside surfaces of a few shells by the epoxy replication process. Testing of two SiC shells for x-ray applications yielded a half energy width of < 15 arcsecs over a wide field of view. Important issues involved in near-net-shaping and machining of these shells are discussed.