X-ray telescope deformation reduction using stress relief features

A stress relief technique is presented to reduce the distortion of X-ray optics from adhesive shrinkage at bonding points. The bonding distortions are particularly relevant for thin-shell mirror optics and need to be minimized to meet subarcsecond angular resolution goals. Thin-shell optics are critical to achieving large collecting areas for X-ray telescopes, such as the Lynx mission concept. A localized topography modification of the optic surrounding the adhesive point has been explored to reduce global distortion. Previous efforts utilized finite element analysis (FEA) to study removal of material around the adhesive joint in an annulus pattern, creating a trench. Current work has improved the finite element model for the trench design as well as shown an experimental verification. These experiments involve using silicon wafers as test mirrors and silicon oxide to mimic stress induced by adhesive shrinkage. The silicon oxide is encompassed by the trench etch, which is used to demonstrate a reduction in global deformation. We present the recent progress made with this stress relief technique.