SUPERMIRROR HARD-X-RAY TELESCOPE

The practical use of a grazing x-ray telescope is demonstrated for har d-x-ray imaging as hard as 40 keV by means of a depth-graded d-spacing multilayer, a so-called supermirror. Platinum-carbon multilayers of 2 6 layer pairs in three blocks with a different periodic length d of 3- 5 nm were designed to enhance the reflectivity in the energy range fro m 24 to 36 keV at a grazing angle of 0.3 deg. The multilayers were dep osited on thin-replica-foil mirrors by a magnetron de sputtering syste m. The reflectivity was measured to be 25%-30% in this energy range; 2 0 mirror shells thus deposited were assembled into the tightly nested grazing-incidence telescope. The focused hard-x-ray image was observed with a newly developed position-sensitive CdZnTe solid-state detector . The angular resolution of this telescope was found to be 2.4 arc min in the half-power diameter. (C) 1998 Optical Society of America.