Chemical Vapor Composites Silicon Carbide for Radiation Hard Optics

A program to develop chemical vapor composite silicon carbide (CVC SiC) mirrors with reflective coatings capable of maintaining high optical performance after exposure to high flux x-ray radiation is proposed. For the Phase I effort, Trex Enterprises' Advanced Materials Group will work with Raytheon Missile Systems to identify low atomic number (low Z) materials whose properties a) are suitable for high reflectance dielectric stack structures, and b) engender low emissivity such that background infrared radiation is minimized. Once suitable candidate materials are identified, Trex will fabricate during Phase I a limited number of test mirrors composed CVC SiC substrates with low Z dielectric stack coatings. These mirrors will be evaluated for optical performance and dielectric stack structural integrity. The proposed Phase I effort is prologue to a Phase II program which, if selected, would entail the fabrication of additional test mirrors for evaluation at a high intensity x-ray facility. While the primary focus of the proposed work is the development of low Z dielectric stacks for CVC SiC mirrors, the findings should be beneficial to radiation hard mirror technologies based on other forms of silicon carbide, and mirror materials in general.