DEVELOPMENT OF ONE DIMENSIONAL ANGULAR CORRELATION OF POSITRON ANNIHILATION RADIATION MEASU REING WIDE MOMENTUM REGION FOR NON-DESTRUCTIVE INSPECTION OF NUCLEAR REACTOR PRESSURE VESSEL

核反应堆压力容器无损检测宽动量区正电子湮灭辐射测量一维角关联法的研制

• 批准号: 12358005
• 负责人: HASEGAWA Masayuki
• 金额: $ 23.09万
• 依托单位: TOHOKU UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12358005/
• 关键词: POSITRON ANNIHILATION; LIFE MANAGEMENT OF NUCLEAR POWER REACTOR; WIDE RANGE MOMENTUM DISTRIBUTION MEASUREMENT; POSITION SENSITIVE GAMMA-RAY DETECTOR; 陽電子消滅; 原子炉圧力容器鋼; 非破壊検査; 角相関; 照射脆化

Ensuring safe operation of nuclear power reactors is a recent urgent issue since the reactors of the first generation are going over their initially designed operating lifetimes. One of the most important problem is the embrittlement of the reactor pressure vessel (RPV) steels by neutron irradiation, which is considered to be caused by the ultrafine precipitation of Cu impurities contained in the RPV steels (〜O.3 %) of the first generation induced by neutron irradiation. However, little is known about the irradiation-induced Cu precipitates or aggregations because it is very difficult to observe them even by current high-resolution transmission electron microscopes (HR-TEM). The aim of this work is to develop a new type of one-dimensional angular correlation of positron annihilation radiation (1D-ACAR) apparatus for non-destructive inspection of the RPV steels. Our final goal is to establish the method, using the apparatus, to analyze the formation process and the structure of the ultr … More afine Cu precipitates, difficult to detect by other techniques, utilizing affinity-induced positron confinement in the Cu precipitate which we have recently found.For the above purpose, we have to develop a new 1D-ACAR apparatus which enables us to measure the momentum distribution of not only conduction electrons but also core electrons with high momentum resolution (〜1x10^<-3>mc). Thus, we developed a pair of position sensitive gamma-ray detectors with high position resolution (〜2 mm), high counting rate (wide effective area : 150 mm x 150 mm) and high time resolution. One detector was mounted on a fixed support, and the other detector was mounted on a support movable vertically. In the next step, the sample chamber for low temperature (〜15K) measurements and the support for the chamber were constructed. Finally, the electric system for the coincidence measurement of a pair of positron annihilation gamma-rays was set up.We performed a test measurement of the new 1D-ACAR apparatus for the evaluation of the performance. A long tail in the high momentum region was observed, which results in high background and poor position resolution. We found that this was caused by the reflection of the scintillation photons at the light-guide surfaces. To remove this effect, the detectors are now improving the setting of the light-guide geometry and the amplifiers for the timing outputs. Less

确保核电反应堆的安全运行是最近的一个紧迫问题，因为第一代反应堆即将超过其最初设计的运行寿命，其中一个最重要的问题是反应堆压力容器（RPV）钢因中子辐照而脆化。这被认为是由于第一代RPV钢中含有的Cu杂质(~O.3%)在中子辐照下引起的超细沉淀所致。人们对辐照诱导的铜沉淀或聚集体了解甚多，因为即使通过当前的高分辨率透射电子显微镜（HR-TEM）也很难观察它们。这项工作的目的是开发一种新型的一维角相关性。我们的最终目标是建立使用该设备来分析RPV钢的形成过程和结构的方法。超细的铜沉淀物，很难通过其他技术检测到，利用我们最近发现的铜沉淀物中的亲和力诱导的正电子限制。为了上述目的，我们必须开发一种新的 1D-ACAR 装置，使我们能够测量不仅具有传导电子的动量分布，而且具有高动量分辨率（~1x10^<-3>mc）的核心电子的动量分布，因此，我们开发了一对具有高位置的位置敏感伽马射线探测器。分辨率（~2 mm）、高计数率（宽有效面积：150 mm x 150 mm）和高时间分辨率。一个探测器安装在固定支架上，另一个探测器安装在可垂直移动的支架上。步骤，搭建了低温（~15K）测量样品室和样品室支架，最后搭建了一对正电子湮没伽马射线符合测量的电气系统。我们进行了测试测量。这用于评估性能的新 1D-ACAR 设备观察到高动量区域的长尾，这导致高背景和差的位置分辨率。我们发现这是由闪烁光子在光处的反射引起的。为了消除这种影响，探测器现在正在改进光导几何结构和定时输出放大器的设置。

项目成果

Y.Nagai et al.: "Role of Vacancy-Solute Complex in the Initial Rapid Age Hardening in an Al-Cu-Mg Alloy"Acta Materialia. 59. 913-920 (2001)

Y.Nagai 等人：“空位-溶质复合体在 Al-Cu-Mg 合金初始快速时效硬化中的作用”材料学报。

永井康介, 長谷川雅幸: "陽電子消滅法によるFe-Cuモデル合金中の微小Cu析出物の解析"金属. 71・8. 742-748 (2001)

永井浩介、长谷川正幸：“利用正电子湮没法分析 Fe-Cu 模型合金中的微小 Cu 析出物”金属 71・8（2001 年）。

Y. Nagai et al.: "Study of Ultrafine Cu Precipitates in Neutron-Irradiated Fe Utilizing Positron Quantum-dot-like States"Material Science Forum. 363-365. 91-93 (2001)

Y. Nagai 等人：“利用正电子量子点态研究中子辐照铁中的超细铜沉淀”材料科学论坛。

Y.Nagai et al.: "Study of Ultrafine Cu Precipitates in Neutron-Irradiated Fe Utilizing Positron Quantum-dot-like States"Material Science Forum. 363-365. 91-93 (2001)

Y.Nagai 等人：“利用正电子量子点态研究中子辐照铁中的超细铜沉淀”材料科学论坛。

Z.Tang et al.: "Density Functional Study of Metastable bcc Copper : Electronic structure and momentum density of positron-electron pairs"Physical Review B. (掲載受理). (2002)

Z.Tang 等人：“亚稳态 bcc 铜的密度泛函研究：正电子对的电子结构和动量密度”Physical Review B.（接受出版）。