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

电子和晶格激发的协同效应对晶体辐照效应的影响

基本信息

批准号：
07455260
负责人：
KINOSHITA Chiken
金额：
$ 3.52万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

项目摘要

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.

我们研究了电离和 PKA（一次原子碰撞）能谱对陶瓷绝缘体物理性能的影响。本研究中研究的陶瓷是化学计量和非化学计量的铝酸镁尖晶石、氧化铝和氧化镁。在 TEM 加速器设施中离子和电子同时照射下进行了微观结构演化的原位观察。我们发现，强烈的电离和/或亚阈值核能，即不产生原子位移的核能，抑制间隙位错环的形成或促进陶瓷中气泡的形成。从电离与核停止功率之比、级联位移能量密度和聚焦电子束通量分布等方面对结果进行了讨论。人们发现低能电子辐射驱动的阳离子扩散对于并发辐射效应的重要性。本研究开发了一种特殊的 TEM 支架，用于在高压电子显微镜中的电子辐射下原位测量电导率。电离辐射在辐射的早期阶段增加了陶瓷绝缘体的电导率（RIC：辐射诱导电导率）。高剂量辐照时位移损伤可能很重要。我们还讨论了热刺激传导的机制，这可能是熔合绝缘体的一个关键问题。