Study of Gaseous Impurity Elements in Cavities with Use of Positrons and Positronium

利用正电子和正电子研究空腔中的气态杂质元素

• 批准号: 63550470
• 负责人: HASEGAWA Masayuki
• 金额: $ 1.22万
• 依托单位: Institute for Materials Research, Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1988
• 资助国家: 日本
• 起止时间: 1988 至 1989
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-63550470/
• 关键词: POSITRON; POSITRONIUM; CAVITY; VOID; RADIATION DAMAGE; VANADIUM; ZEOLITE; SEPIOLITE; グラファイト

In metals and semiconductors, there are cavities which are induced by bombardment of high energy particle or produced during sample preparation processes. In silicate compounds (zeolites and sepiolite) there are structural cavities. These cavities have been object of basic research because of their important roles in physical, mechanical and chemical properties such as dimensional stability of heavily irradiated metals, and catalytic behavior of synthetic zeolites.In this study positrons are used to investigate the interiors of cavities, especially state and behavior of gaseous element molecules within them.1) Positronium in cavities (voids) in vanadium Positron ACAR (angular correlation of annihilation radiation) and life measurements have been done on neutron-irradiated vanadium samples with controlled impurity contents of oxygen or carbon. It has been shown that contamination of voids with oxygen impurities, presumably on the void internal surface, leads to Ps formation, but not wit … More h carbon impurities. From the annealing behavior of narrow component due to para-Ps, the Ps formation increases with annealing temperature up to 600 ﾟC but subsequently decreases with increasing the temperature. This suggests that segregation of oxygen impurities onto the void surface up to 600 ﾟC followed by resolution into the matrix. Lifetime experiments shows a very rapid Ps ortho-para conversion rate and its large temperature dependence.2)Positron annihilation in zeolites and sepiolite. Positron annihilation ACAR measurements have been carried out for series of synthetic zeolite powders and single fibers of natural sepiolite. All of the samples showed marked narrow para-Ps peaks af the top of the ACAR curves. From a simple model calculation, the Ps atoms are found to exist as free particle in the structural cavities, such as the alpha-cages in the MS-3A zeolite and the 1-dimensional cavity channel in sepiolite. Oxygen molecules influence motion and reactions of Ps in these cavities.Cavities in neutron-irradiated nickel and stainless steel and in graphite have been studied by positron annihilation method. Less

在金属和半导体中，存在由高能粒子轰击引起或在样品制备过程中产生的空腔。在硅酸盐化合物（沸石和海泡石）中存在结构空腔。这些空腔在强辐射金属的尺寸稳定性和合成沸石的催化行为等物理、机械和化学性质中起着重要的作用，已成为基础研究的对象。在这项研究中，正电子被用来研究空腔内部，特别是其中气体元素分子的状态和行为。1)对控制氧或碳杂质含量的中子辐照钒样品进行了正电子湮灭辐射角相关（ACAR）和寿命测量。研究表明，氧杂质污染了孔洞，可能是在孔洞的内表面，导致了Ps的形成，而不是更多的氢碳杂质。从窄组分由于para-Ps的退火行为来看，当退火温度达到600℃时，Ps的形成增加，但随后随着温度的升高而减少。这表明氧杂质在高达600°C的空位表面偏析，然后分解到基体中。寿命实验表明，Ps的正对位转化率非常快，且对温度的依赖性很大。沸石和海泡石中的正电子湮没。对一系列合成沸石粉和天然海泡石单纤维进行了正电子湮没ACAR测量。所有样品在ACAR曲线的顶部都显示出明显的窄para-Ps峰。通过简单的模型计算，发现Ps原子以自由粒子的形式存在于MS-3A分子筛的α笼和海泡石的一维腔道等结构腔中。氧分子影响这些空腔中Ps的运动和反应。用正电子湮没法研究了中子辐照镍、不锈钢和石墨中的空腔。少

项目成果

Masayuki Hasegawa: "Positronium in voids in metals(Jnuited Paper)" Positron Annihilation,Ed.by L.Dorikens-Vanpraet,M.Dorikens and D.Segers,World Scientific. 73-75 (1989)

长谷川雅之：“金属中空隙中的正电子（Jnuited Paper）”正电子湮灭，L.Dorikens-Vanpraet、M.Dorikens 和 D.Segers 编辑，世界科学。

Yoshimi,Tsuchiya: Proc.of the 8th Int.Conf.on Positron Annihilation,Gent,Belgium,23 Aug.-3 Sept.1988. (1989)

Yoshimi,Tsuchiya：第 8 届国际正电子湮灭会议记录，比利时根特，1988 年 8 月 23 日至 9 月 3 日。

Yasuo,Ito: Applied Physics. A45. 193-201 (1988)

伊藤康夫：应用物理学。

E. Kuramoto, N. Kikuchi, D. Irisawa, M. Takenaka and M. Hasegawa: "Positron Annihilation ACAR Measurement of Neutron-Irradiated Fe-Cr-Ni Alloys" Positron Annihilation, Ed. by L. Dorikens-Vanpraet, M. Dorikens and D. Segers, World Scientific, p446-448, (19

E. Kuramoto、N. Kikuchi、D. Irisawa、M. Takenaka 和 M. Hasekawa：“中子辐照 Fe-Cr-Ni 合金的正电子湮灭 ACAR 测量” 正电子湮灭，Ed。

Eiichi Kuramoto: "Positron Annililation ACAR Measurement of Neutron-Irradiated Fe-Cr-Ni Alloys" Positron Annihilation,Ed.by L.Donkeus-Vanpraet,M.Dorikeus and D.Segers,World Scientific. 824-826 (1989)

Eiichi Kuramoto：“中子辐照 Fe-Cr-Ni 合金的正电子湮灭 ACAR 测量”正电子湮灭，L.Donkeus-Vanpraet、M.Dorikeus 和 D.Segers 编辑，World Scientific。