Development of foil segments for large astronomical x-ray telescopes

Various future projects in X-ray astronomy and astrophysics will require large segments with multiple thin shells or foils. The large Kirkpatrick-Baez modules, as well as the large Lobster-Eye X-ray telescope modules in Schmidt arrangement may serve as examples. All these space projects will require high quality and light segmented shells (bent or flat foils) with high X-ray reflectivity and excellent mechanical stability. Generally, the X-ray reflecting flats and foils are well suited for numerous applications such as grazing incidence X-ray flat mirrors, bent X-ray mirrors, various X-ray focusing elements, X-ray wave-guides, X-ray planar capillaries, lobster-eye type X-ray elements etc. We report here on the development of X-ray reflecting one-and double-sided flats as well as foils considered as segments for future astronomical X-telescopes. Several test modules have been designed and realized. Theoretical aspects and experimental results are discussed especially from the point of view of potential applications.