RESUMO
The He-II (λ=30.4 nm) emission line is one of the spectral channels chosen to study solar corona. This Letter reports on investigations of novel beryllium (Be)/magnesium multilayer coatings which, when incorporated beneath a protective bilayer of aluminium and Be, ensure particularly high-reflection coefficients of up to 56%, a spectral width of Δλ=1.6 nm (λ/Δλ≈20), and high temporal stability.
RESUMO
The effect of Be layers on the reflection coefficients of Mo/Be/Si multilayer mirrors in the extreme ultraviolet (EUV) region is reported. Samples were studied using laboratory and synchrotron based reflectometry, and high-resolution transmission electron microscopy. The samples under study have reflection coefficients above 71% at 13.5 nm and more than 72% at 12.9 nm in a near normal incidence mode. Calculations show that by optimizing the thickness of the Be layer it should be possible to increase the reflection coefficient by another 0.5-1%. These results are of considerable interest for EUV lithography.
