Design and fabrication of supermirrors for (2–10 keV) high resolution X-ray plasmas diagnostic imaging

We have developed non-periodic W/SiC multilayer mirrors (“supermirrors”) specifically designed to reflect photons between 2 and 10 keV. The mirrors were designed and optimized with a homemade calculation code. The supermirrors are designed to work at a nominal 0.7° grazing incidence with reflectivity above 35% in almost the entire energy range. The multilayers have been deposited by magnetron sputtering. Grazing incidence X-ray reflectance at 8 keV (0.154 nm) was made using a laboratory source. Reflectance measurement over the whole range was made at Physikalisch-Technische Bundesanstalt laboratory (PTB), the synchrotron radiation facility BESSY II, in Berlin. In addition to X-ray reflectance, multilayer thickness, refractive indices and roughness were characterized. The experimental results show good agreement with theoretical computations.