| Project/Area Number |
07558187
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
エネルギー学一般・原子力学
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| Research Institution | Osaka University |
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Principal Investigator |
IZAWA Yasukazu Osaka University, Institute for Laser Engineering, Professor, レーザー核融合研究センター, 教授 (10029316)
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| Co-Investigator(Kenkyū-buntansha) |
SAKABE Shuji Osaka University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (50153903)
FUJITA Hisanori Osaka University, Institute of Laser Engineering, Associate Professor, レーザー核融合研究センター, 助教授 (70135755)
NIKI Hideaki Fukui University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (00135758)
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| Project Period (FY) |
1995 – 1997
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| Project Status |
Completed (Fiscal Year 1997)
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| Budget Amount *help |
¥6,600,000 (Direct Cost: ¥6,600,000)
Fiscal Year 1997: ¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 1996: ¥4,200,000 (Direct Cost: ¥4,200,000)
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| Keywords | laser isotope separation / gadolinium / selective excitation / linear polarization / polarization selection rule / three-step photoionization |
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| Research Abstract |
In the absorption spectrum of atomic Gd, the isotope shifts are very small compared with the widths of hyperfine structures of the odd isotopic elements. Therefore the selective photoionization scheme based on the polarization selection rules seems to be suitable to separate Gd-157. In this scheme three linearly polarized laser pulses are used to prepare aligned states. Ionization of the even isotopes in inhibited by the selection rules, while the hyperfine interactions in the odd isotopes allow selective ionization.
The absorption spectrum of Gd for the transitions applicable to the 1st and 2nd steps in the 3-step photoionization scheme were measured and the isotope shifts and the hyperfine structure constants were determined. By using the excitation pathway with J=2*2*1*0, the enrichment of Gd-157 up to 80% was demonstrated. The selectivity of this method, however, will be lost by an external magnetic field because the intermediate-state alignment is destroyed by the magnetic field that finally leads to ionization of the even isotopes. The effects of magnetic field on isotope selectively was analyzed and the condition for high selectivity was discussed.
The charge transfer collision cross section between the selectivity photoionized Gd ions and Gd atoms were experimentally evaluated. The atomic vapor density to maintain high selectivity was also discussed.
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