Carbon/Titanium multilayers as soft-x-ray mirrors for the water window.

C/Ti multilayers with a period thickness of 2.1-2.7 nm were produced by electron-beam evaporation in ultrahigh vacuum as soft-x-ray mirrors in the water window (lambda = 2.3-4.4 nm). For smoothing the individual interfaces and thus enhancing the total reflectance, each layer was ion polished with an Ar(+) ion beam after deposition. For a multilayer of 85 bilayers, a reflectance of approximately 11% at an angle of incidence of 59 degrees (with respect to the surface normal) by use of s-polarized radiation at a wavelength of 2.77 nm was achieved.

Carbon buffer layers for smoothing superpolished glass surfaces as substrates for molybdenum /silicon multilayer soft-x-ray mirrors.

Zerodur and BK7 glass substrates (developed by Fa. Glaswerke Schott, D-55014 Mainz, Germany) from Carl Zeiss Oberkochen polished to a standard surface roughness of varsigma = 0.8 nm rms were coated with a C layer by electron-beam evaporation in the UHV. The roughness of the C-layer surfaces is reduced to 0.6 nm rms. A normal-incidence reflectance of 50% at a wavelength of 13 nm was measured for a Mo/Si multilayer soft-x-ray mirror with 30 double layers (N = 30) deposited onto the BK7/C substrate, whereas a similar Mo/Si multilayer (N = 30) evaporated directly onto the bare BK7 surface turned out to show a reflectance of only 42%.