Improvement of the Microstructure and X-ray Performance of Ultrathin Ru/C Multilayer Mirror after High Temperature Treatment

Ru/C multilayer mirrors with a period of 2.5 nm and 150 bilayers were studied under high-temperature annealing long-term storage. A general increase in the reflectivity was observed after at different temperatures from 300 to 700 °C, during which maximum enhancement around 14% obtained 600 °C. The highest reflectance measured 8 keV reached 69% °C annealing. This accompanied by 6% expansion layer period, could be mainly attributed carbon layers. surface roughness not affected annealing, whereas polycrystallization Ru crystallographic planes parallel interfaces enhanced. Combining transmission-electron microscopy measurements, it found that interdiffusion C-on-Ru interface significantly suppressed. decreased interdiffusion, enhanced optical contrast, larger main reasons for increased reflectance. annealed remained intact 13 months storage air, also demonstrated significant temporal stability.