2007 Fiscal Year Final Research Report Summary
Development and application of crystal structure analysis technology with polarized X-ray multiple wave method
| Project/Area Number |
18540310
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Condensed matter physics I
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| Research Institution | The University of Tokyo |
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Principal Investigator |
OKITSU Kouhei The University of Tokyo, Graduate School of engineering, Research Associate (50323506)
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| Co-Investigator(Kenkyū-buntansha) |
IMAI Yasuhiko The University of Tokyo, SPring-8, Researcher (30416375)
YODA Yoshitaka The University of Tokyo, SPring-8, Researcher (90240366)
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| Project Period (FY) |
2006 – 2007
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| Keywords | X-ray diffraction / Dynamical diffraction thoery / Simultaneous diffraction / Polarization / Phase problem / Computer simulation / Takagi-Taupin equation / Refraction imaging |
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| Research Abstract |
Takagi-Taupin equation (T-T theory) has been widely known since its derivation by Takagi as an X-ray dynamical diffraction theory that can deal with wave fields in a deformed crystal. The Ewald-Laue dynamical theory (E-L theory) has been considered as an principle X-ray dynamical diffraction theory while the T-T theory has been considered to be a special theory However, it should be noted that the E-L and T-T theories are equivalent to each other. The T-T theory describes the X-ray wave fields in a crystal in the real space while the E-L theory describes those in the reciprocal space. The E-L theory was extended to three-beam case in the late 1969's and a numerical method to solve it was given by Colella in 1974. However, the T-T theory has been considered not able to be solved for multiple wave condition until the present author gave a numerical method to solve it for multiple wave cases.
Furthermore, the T-T theory can be solved numerically but only for plane-wave and spherical wave X-ray incidence condition but also for an arbitrary X-ray incidence condition. Recently Ando and his coworkers studies on refraction contrast imaging using an analyzer crystal that can obtain clear images even when normal absorption images cannot be obtained at all due to the faint absorption inhomogeneity of object. In 2007 fiscal year, the present author made a study focusing on computer simulation of refraction contrast imaging. The computer-simulated refraction contrast images well agreed with practical images obtained by experiments. Therefore, it has come to be able to evaluate favorable condition required to the analyzer crystal. Further, X-ray refraction computed tomography (CT) and tomothynthes images that can be obtained by rotating the object, can be expected before experiment. This simulation was performed by taking advantage of the feature of T-T equation that can deal with an arbitrary incidence condition of X-rays.
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