Fabrication and assembly of Flex Module prototypes

Achieving sub-arcsecond resolution in combination with lightweight, large-effective-area mirrors for future X-ray telescope missions is a challenge. Segmented grazing-incidence X-ray mirror designs feature thin, tightly nested mirrors that are easily deformed from coating and assembly. The process flow of building X-ray mirror modules can be reassessed to correct for these deformations. We introduce Flex Modules, which are epoxy-free all-glass mirror assemblies in which the mirror segments (Flex Segments, which have a flexure-supported mirror surface) are simultaneously figured and aligned after coating and assembly. In this paper, we present the Flex Module component fabrication and assembly processes and demonstrate these on a flat, uncoated Flex Module prototype. We fabricate flat Flex Segments and glass spacers using ultrafast laser-assisted chemical etching, and we weld the spacers to the Flex Segments using an ultrafast laser. To demonstrate more process steps necessary for building Flex Modules, we also build an uncoated, slumped mirror module prototype. Flex Modules are a promising new approach to building lightweight, high-resolution, large-effective area X-ray mirror modules.