Multilayer supermirror coating for hard x-ray telescope

We present an approach to obtaining a high throughput hard x-ray telescope based on combining present replication technologies with multilayer supermirror coating. Fabrication of Pt/C supermirror using specially designed sputtering system has been tried and properties of x-ray reflection such as 1-st and 2-nd order bragg reflection peak profile, energy dependence of x-ray reflection, interfacial roughness were measured. Optimization of coating para meters such as 2D, total pair number, thickness ratio of Pt and C were investigated from points of view of theoretical simulation and fabrication technique in order to get maximum effective area and field of view of telescope system. Based on currently optimized parameters, we designed telescope system with 45 cm outer diameter, 2-stage 20 cm mirror length and focal length of 8 meters. It was found that expected effective area of four such telescopes is 320 cm2 for the x-ray energy < 40 keV. Application of this type of telescope of balloon experiment to reveal hard x-ray image of clusters of galaxies or supernova remnant is also planned.