We deal with the recent progress in the fabrication of the graded Co/C multilayer mirrors to be used in a 21x Schwarzschild objective (SO) operating at the wavelengths near 4.5 nm ("carbon window" region). The peak reflectivity of flat Co/C mirrors was measured to be 14.8% (wavelength of 4.48 nm, incidence angle of 5 degrees). The reflectivity curves of the spherical mirrors achieved 3%-6%, with the spectral matching accuracy being Deltad approximately 0.008 nm (Deltad/d approximately 0.3%). As a result the SO demonstrates a full working aperture (N(A) approximately 0.2) operation with the total throughput of 0.25%.

The tribological behavior of carbon/silicon bi-layer coatings deposited on a silicon substrate by DC magnetron sputtering was assessed and compared to that of amorphous carbon and silicon coatings. The motivation was to develop a wear resistant coating for silicon using thin layers of amorphous carbon and silicon. Wear tests were conducted by sliding a stainless steel ball against the coating specimens under applied normal loads in the range of 20 * 50 mN. Results showed that the wear rate of the bi-layer coating was strongly dependent on the ratio of thickness between the carbon and silicon layers. The wear rate of the bi-layer coating with 25 nm thick carbon and 102 nm thick silicon layers was about 48 and 20 times lower than that of the single-layer amorphous carbon and amorphous silicon coating, respectively. In addition, the steady-state friction coefficient of the bi-layer coating could be decreased to 0.09 by optimizing the thickness of the layer. Finally, a model for the wear reduction mechanism of the carbon/silicon bi-layer coating was proposed.

The paper deals with the recent results of the experiments on soft X-ray imaging of various carbon-containing objects: biological samples, artificial carbon fibres, graphite slices, etc. The working wavelength was chosen to be 4.5 nm due to high penetration ability of these soft X-rays in the carbon materials. The experimental set-up included: laser plasma Xray source (generated with the 2nd harmonics of Nd:YAG laser), scandium-based thin-film filter and highly reflective spherical multilayer mirror. The Co/C multilayer's reflectivity was measured to be about 15 % at normal incidence that was high enough to produce soft X-ray images using single nanosecond exposure. The work demonstrates a possibility to produce high contrast images outside "water window" region for study of relatively thick (tens of microns) unstained samples that may lead to new fields of applications of the soft x-ray microscopy

No abstract

The paper deals with the recent progress in fabrication of the graded multilayer mirrors to be used in a 21X Schwarzschild objective operating at the wavelengths about 4.5 nm ("carbon window" region). The graded Co/C reflective multilayer coatings were fabricated using DC-magnetron sputtering. Mask-assisted deposition was used to create the required radial variation of the multilayer period. Accuracy of the multilayer's parameter measurements and quality of nm-scale layer deposition were improved significantly with application of a number of new methods and approaches. The soft X-ray measurements were conducted at the ALS 6.3.2 beamline to quantify the graded periods on concave and convex mirrors of the Schwarzschild objective. They demonstrated that the reflectivity curves were adjusted with the accuracy of about 0.008 nm (0.3%) over the entire mirror surfaces. The total throughput of the objective with full working aperture (N A ~ 0.2) is estimated to be as high as 0.25%.