We present our design and fabrication scheme of a supermirror for hard x-ray telescopes to improve the performance of reflection. Supermirrors are designed to achieve target reflectivity profiles with small ripples in the interesting energy range with a limited number of layer pairs. Starting from conventional design methods, we optimized the thickness distribution of the structure using a numerical approach with the merit function established for this application. As an example, a platinum–carbon supermirror structure of 123 layer pairs with a varying d-space of 2–6 nm was designed to enhance the reflectivity in the energy range from 11 to 55 keV with a flat top at a grazing angle of 0.28 deg. The multilayer thus designed was deposited on a float glass by our DC magnetron sputtering system. The reflectivity profile was successfully measured to be ∼20% with little oscillation in all energy band of interest.
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