Development of high-wavelengh-resolution XUV multilayr

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The purpose of this research project is to develop a high performance X-ray multilayr mirror and an X-ray CCD camera, which are primary components of an X-ray telescope. A multilayr mirror consists of multiple layrs of High-Z (atomic number) and low-Z materials, and reflects normal-incidence X-rays with wavelength satisfying the Bragg condition.Multilayr mirror with system wavelength resolution lambda/DELTA lambda as high as 30-50 is required for the diagnostics of the cosmic plasma with temperature 1-20 MK.Such a high wavelength resolution was realized by increasing the number of the layr pairs contributing to the reflectance, i.e. by selecting less absorbing materials for both the reflector and the spacer and by decreasing thickness of the reflector. We fabricated two types of the multilayr mirrors (silicon carbide reflector (20% thickness of the layr period) with aluminum spacer, MoSi reflector (25% thickness) with silicon spacer) and found lambda/DELTA lambda - 25-30, and the peak reflectivity 13-20%. This wavelength resolution is close to the value obtained with the numerical simulation, and is considerably higher than the value obtained with the conventional Mo/Si multilayr.We have also developed the wave-trap on top of the multilater that traps the intense HeII line at 304ALPHA. The ratio of the reflectivity at the desired wavelength (211A in this case) and at 304A reaches 100, which allows us to make contamination-free observations at the desired wavelength. We have also measured the quantum efficiency of the back-illuminated CCDs.