1989 Fiscal Year Final Research Report Summary
A Method of Independent Determination of the Temperature Factor of Each Atom in a Crystal of Teo Elements.
| Project/Area Number |
63460227
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
結晶学
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| Research Institution | Nihon University |
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Principal Investigator |
UNO Ryosei Nihon University, Appl. Phys., Prof., 文理学部, 教授 (00058661)
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| Co-Investigator(Kenkyū-buntansha) |
OHSUMI Kazumasa National Inst. High E., Assit, Prof., 助教授 (70011715)
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| Project Period (FY) |
1988 – 1989
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| Keywords | Synchrotron Radiation / X-ray Powder Diffractometer / X-ray Anomalous Dispersion / Temperature Factor |
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| Research Abstract |
1. To improve the system to follow the SOR beam position made last year, a copper plate was used as a SOR beam scatterer and an integrating circuit was ariaed which integrated 256 times the X-ray intensity in one scanning line of X-ray TV. The obtained X-ray intensity distribution was used to estimate the beam position. The sensitivity of detecting a shift of the beam was <plus-minus>0.03 mm. It was enough for our purpose to keep the relative beam position to the diffractometer within <plus-minus>0.3 mm and to keep the wavelength of monochromated X-ray within <plus-minus>0.0001 A^^ﾟ.
2. Diffraction measurements at 1.19735 A^^ﾟ (lambda_L) and 1.19462 A^^ﾟ (lambda_S) were carried out on GaAs powder sample. As for the anomalous dispersion correction terms of Ga and As, f_<GL>'=f_<GS>', f_<AL>'=f_<AS>' and f_<AL>"=f_<AS>", but f_<GL>'=0.492 and f_<GS>'=3.886. At lambda_S the diffracted intensity was measured by an SSD to separate the diffracted intensity from that of the phosphorescent X-rays.
3. The reflections of odd indices from the GaAs powder sample are the mixture of equal number of h+k+1=4n+l lines and h+k+1=4n-l lines. Therefore we can obtain |F_S(hk1)|^2-|F_L(hk1)|^2=16(f_<GS>"^2-f_<GL>"^2) exp (-2B_G(sinrhets/lambda)^2).
From measured values of the left hand side, the temperature factor of Ga, B_G, can be obtained independently. However obtained value of B_G is about two times larger than obtained from measurements at CuKalpha by usual method at present, mainly due to insufficient accuracy in the measurement.
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