Determination of optical constants of scandium films in the 20-1000 eV range

The transmittance of thin films of Yb deposited by evaporation in ultra high vacuum (UHV) conditions have been investigated in the 23-1,700 eV spectral range. Transmittance measurements were performed in situ on Yb films deposited over grids coated with a thin, C support film. Transmittance measurements were used to obtain the extinction coefficient of Yb films at each individual photon energy investigated. The energy range investigated encompasses M, N, and O edges of Yb. The current results, along with data in the literature, show that Yb has an interesting low-absorption band in the ∼12-24 eV range. The promising characteristics of Yb as a filter material in this region requires the development of a protection material due to the reactivity of Yb under normal atmosphere. The low absorption of Yb in the above range makes it also a candidate for a component of multilayer coatings in a spectral region in which few developments have been performed due to the lack of low absorption materials. The f1 sum-rule was applied to extinction coefficient data in the whole spectrum that included the current data along with those of the literature, resulting in a value of 70.26, which is close to the expected value of 69.32.