Fundamental research on low-loss X-ray multi-layer waveguide and high performance X-ray functional device

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Based on theoretical and experimental examination, we could obtain good results in fundamental research of X-ray waveguides and functional devices.1.Making the hypothesis of atom to be a dielectric cylinder, we analyzed reflection and scattering characteristics of X-rays at the atomic level,using BEM.We applied parallel BEM algorithm to reduce the computation time, and we are now able to analyze with the model having about 150 cylinders.2.Considering the motion of electron within the atom for analyzing equivalent refractive index of atom, we could analyze X-ray scattering of a single atom using an inhomogeneous refractive index scattering model. Energy level f electron affected by X-rays is used as a parameter in this model. Strong correlation between electrons excited due to X-rays and index distribution, and also the correlation of results of X-ray intensity distribution analysis with the index distribution within the atom were confirmed. Further, by the comparison with refractive in … More dex of materials obtained experimentally, it was confirmed that the derived refractive index distribution shows similar dispersion characteristics, and this indicates the appropriateness of the obtained results.3.In addition to Si/Mo, Pt which had been used for this research as materials of the X-ray multi-layer mirror, we chose Ag/La and Rh/Ce and explored the dependence of wavelength, number of layers and incident angle. Making the hypothesis of the incident angle to be near critical angle as in fiber transmission, we optimized the relectivity, which resulted in good reflectivity characteristics.4.We examined the focussing characteristics of tapered waveguide probes. Three different tapered waveguide configurations have been considered, viz., linear type, concave type and convex type. According to the results, it was concluded that linear taper would be preferred when the output core size is smaller than the wavelength and convex type taper would be preferred when the output taper size becomes larger than the wavelength of X-ray used.5.The electromagnetic fields in X-ray gradient fiber with random refractive index media are studied statistically. We found that the loss varies rapidly with the radius of the fiber when the correlation length of the fluctuation is larger than the spot size, and the loss becomes small but does not varies very much with the radius when the correlation length is smaller than the wavelength.6.We have calculated photonic band structures for 2-dimensional crystals of Mo and C. The difinite photonic band gap is not confirmed. The photonic band structure provides a basis for the X-ray waveguide.In future, we must examine reduction of loss on X-ray waveguides. According to the results of research project, it has become possible to study low-loss X-ray waveguides and functional devices of high-performance. Less