Aperiodic Mirrors Based on Multilayer Beryllium Systems

Aperiodic multilayer mirrors (AMMs) optimized for uniform reflection within the bands of 16.5–21 and 28–33 nm are calculated by the genetic algorithm for the CORTES project. The comparative characteristic of traditional Mo/Si AMMs and beryllium-containing Mo/Be, Mo/Be/Si, Al/Be, and Mg/Be systems is given. It is demonstrated that Mo/Be/Si AMM is more preferable within the wavelength range of 16.5–21 nm, while Mg/Be AMM with a protective aluminum coating is more preferable within the band of 28–33 nm, being two and a half times superior to the corresponding Mo/Si AMM in its reflectivity.