Technique of Dynamical Observation of Atomic Scale Structural Change and Initial Stage of Neutron Radiaton Damage

仅对中子辐照作了简要描述：裂变反应堆JMTR的控制辐照取得了稳步进展，特别是通过在名古屋大学高压电子显微镜实验室建立辐射Harzard控制区，特别强调了中子辐照样品的电子辐照的第一次成功。根据碰撞级联产生的极小点缺陷团簇在电子辐照下的行为，可靠地确定了它们的性质。研究了不同材料中中子辐照引起的缺陷的退火行为，以了解中子级联中团簇的形成机制和中子束辐照过程中温度变化的影响。另外，高能电子辐照下各种缺陷行为的动态观察揭示了以下内容。(1)小间隙团簇的一维易运动是中子辐照诱发位错结构的晶体取向依赖性的原因。(2)通过对小缺陷团簇生长和收缩的观察和分析，得出了点缺陷反应的随机起伏，这使我们理解了由碰撞级联形成的胚胎生长间隙缺陷的成功几率很小。(3)用局域电子辐照实验检测了间隙原子的一维运动；(4)用间歇电子辐照技术测量了基本缺陷参数。

Only the brief description is made on neutron irradiation : a steady progress has been made with controlled irradiation with the fission reactor JMTR,referred to the results of fusion neutron irradiaton with RTNS-II.Specially emphasized is the first success of the electron irradiation of neutron irradiated samples, by establishing radiation harzard control area in the High Voltage Electron Microscopy Laboratory of Nagoya University. The nature of very small point defect clusters produced by collision cascades was identified reliably from their behavior under electron irradiation. Annealing behavior of neutron irradiation induced defects in various materials was pursued to understand both the formation mechanism of the clusters from cascades and the effect of temperature variation during eutron irradiaton.The other dynamical observation of various defect behavior under high energy electron irradiation disclose the followings. (1) One dimensional easy motion of small interstitial clusters was found to be responsible for the crystallographic orientation dependence of neutron-irradiation-induced dislocation structures. (2) Stochastic fluctuation of point defect reactions deduced from the observation and analysis of the growth and shrinkage of small point defect clusters made us to understand the very small success probability of the growth of interstitial clusers from the embryo made by collision cascades. (3) One dimensional motion of interstital atoms was detected by localized electron irradiation experiment, and (4) fundamental defect parameters were measured by the development of intermittent electron irradiation technique.