| Research Abstract |
1. Assuming atom to be a perfect conducting cylinder, we analyzed reflection and scattering characteristics of X-rays at the atomic level, using BEM.Assuming a group of atoms within the crystal to be a dielectric cylinder, we analyzed transmission and scattering characteristics of X-rays incident on the crystal and were able to show the scattering intensity with respect to the array of atoms.
2. Considering the motion of electrons within the atom, we could analyze X-ray scattering of a single atom using an inhomogeneous refractive index scattering model. Energy level of 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. This analysis for a single atom was extended to the analysis multiple atom models.
3. In addition to Si/Mo, Pt which had been used for this
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research as materials of the X-ray multi-layr mirror, we chose Ag/La and Rh/Ce and explored the dependence of wave length, number of layrs and incident angle. Assuming the incident angle to be near critical angles as in fiber transmission, we optimized the reflectivity, which resulted in good reflectivity characteristics.
4. In the research of X-ray shield, by applying the wave absorber used in microwave region to a multi-layr structure we analyzed the characteristics in the region of X-rays. As a result, as a feature of the multi-layr with gradient type refractive index, we could see that absorption efficiency could be increased in order to reduce reflection and transmission.
5. Total refraction and transmission at the near critical angle were analyzed. The dependence of the medium constants and the change due to spatial spectrum were examined. Propagation characteristics at the curvature were analyzed using a curved X-ray focusing waveguide, and mode conversion and spreading of beam spot of this model were investigated. As a result we could gain a fundamental knowledge of an X-ray waveguide and the propagation characteristics.
6. According to the theoretical results, focusing of X-rays in graded-index type waveguide was understood. Focusing of a gauss beam in a more realistic model with loss at the core was also explored. In addition, electric field distribution inside and outside of tapered waveguide probe, with an X-ray plane wave input, was analyzed using FEM and BEM.The focusing of the X-ray plane wave was confirmed. Less
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