The B4C/Mo/Si high reflectivity multilayer mirror was designed for He-II radiation (30.4 nm) using the layer-by-layer method. The theoretical peak reflectivity was up to 38.2% at the incident angle of 5 degrees. The B4C/Mo/Si multilayer was fabricated by direct current magnetron sputtering and measured at the National Synchrotron Radiation Laboratory (NSRL) of China. The experimental reflectivity of the B4C/Mo/Si multilayer at 30.4 nm was about 32.5%. The promising performances of the B4C/Mo/Si multilayer mirror could be used for the construction of solar physics instrumentation.

The interferometry with an X-ray laser as probe is an important tool of diagnosing the electron density of a high temperature and dense plasma. A successful experiment of diagnosing the density of a CH plasma was demonstrated by using a Ni-like Ag X-ray laser as a probe and a Mach-Zehnder interferometer as instrument under the Shenguang II laser facility. The legible interferogram indicating the information of electron density was obtained.

Ultra-short-period W/C multilayers having periodic thickness range of 1.15---3.01 nm have been fabricated for soft X-ray optics using the high vacuum direct current (DC) magnetron sputtering system. These multilayers were characterized by low-angle X-ray diffraction (LAXRD) and transmission electron microscope (TEM). The results show that the multilayer thin films with periodic thickness more than 1.5 nm have clear W-C interface and low roughness. But the structure of the periodic thickness below 1.5 nm is not clear. Finally, three ways to improve the performance of the multilayers are suggested.

In this paper, a depth-graded C/W multilayer mirror with broad grazing incident angular range, consisting of three multilayer stacks, each of which has different period thickness d and the layer pair number, was designed and fabricated by direct current (DC) magnetron sputtering. For calculating the definite performance of such a mirror, the saturation effects of the interfacial imperfection, such as interface roughness and diffusion, were emerged. The reflectivity of the mirror was measured by the X-ray diffraction (XRD) instrument at Cu Kα radiation (λ = 0.154 nm), the measured reflectivity was about 30% in a broad grazing incident angular range (0.55---0.85 deg.). By the fitting data, the thickness of each layer is almost same as the one designed and the roughness in the multilayer is about 0.85 nm, which is larger than the prospective value of 0.5 nm.