1996 Fiscal Year Final Research Report Summary
結晶の照射効果に及ぼす電子励起および格子励起の相乗効果
| Project/Area Number |
07455260
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Physical properties of metals
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| Research Institution | KYUSHU UNIVERSITY |
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Principal Investigator |
KINOSHITA Chiken Kyushu University, Faculty of Engineering, Professor, 工学部, 教授 (50037917)
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| Co-Investigator(Kenkyū-buntansha) |
YASUDA Kazuhiro Kyushu University, Faculty of Engineering, Research Associate, 工学部, 助手 (80253491)
SHIIYAMA Kenichi Kyushu University, Faculty of Engineering, Research Associate, 工学部, 助手 (30243900)
MATSUMURA Syo Kyushu University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (60150520)
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| Project Period (FY) |
1995 – 1996
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| Keywords | Ceramics / MgAl_2O_4 / Al_2O_3 / irradiation / TEM / radiation damage / ionization / displacement |
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| Research Abstract |
We have investigated the role of ionization and PKA (primary knock on atom) energy spectrum on the physical properties in ceramic insulators. The ceramics studied in this study are stoichiometric- and nonstoichiometric- magnesium aluminate spinel, alumina and magnesia.
In situ observations of microstructural evolution were carried out under concurrent irradiation with ions and electrons in TEM-accelerator facilities. We have found that the intense ionization and/or subthreshold nuclear energy, that is the nuclear energy which does ont produce displacements of atoms, suppress the formation of interstitial dislocation loops or promote the formation of bubbles in ceramics. Results were discussed in terms of ratio of ionizing to nuclear stopping power, energy density in displacement of cascades and the flux distribution of focused electron beam. An importance of cation diffusion driven by low energy electron irradiation has been found for the concurrent irradiation effects.
A special TEM holders has been developed in this study for in situ measurements of electrical conductivity under electron irradiation in a high voltage electron microscope. The ionizing radiation increases electrical conductivity (RIC : radiation induced conductivity) in ceramic insulators at the early stage of irradiation. Displecement damage can be important at high dose irradiation. We have also discussed the mechanism of thermally stimulated conductivity which can be a critical problem for fusion insulators.
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