Breadboard micro-pore optic development for x-ray imaging

Technology associated with x-ray optics for missions such as ESA's XMM-Newton are not compatible with the demanding mass requirements for planetary explorers. Glass micro-pore optics are an enabling technology for future ESA missions to fly remote, planetary, x-ray imagers, by facilitating mass and volume reduction. Activities pursued by ESA have developed manufacturing techniques for micro-channel plates to produce high quality, square fibres, which are used to form glass plates containing square micro-channel pores, with diameters from 10 μm and fill factors around 60%. Matched pairs of plates can be deformed under heat and pressure to form spherical surfaces, such that each plate approximates the radius of one part of the tandem pair of a Wolter I configuration. In such a configuration the tangential walls of the concentric rings of pores are used as the grazing incidence, reflective surfaces that focus x-rays. The monolithic structure of the plates allows dense packing of the rings of x-ray mirrors and simplifies mounting, especially with respect to thermal and mechanical considerations. To improve x-ray reflectivity, processes to coat the channel surfaces with elements such as Ni and Ir have also been investigated. This paper discusses the design of a structure to support the optic segments and assembly of the optics into a structure. Pairs of plates must be aligned into tandems and fixed to form segments of the x-ray optic. Each tandem pair must be aligned into a structure which will support the plates through thermal and mechanical loading. A structure has been designed to allow assembly of the optic within tolerances justified by analysis. Replacement of individual tandems is possible. Thermal and mechanical analyses have been performed to assess the performance and survivability of the optic under loads. An assembly plan has been designed to allow maximisation of the effective area of the optic and ensure its best performance.