中文摘要：

利用SEM和幔正电子束分析（SPBA）方法研究了不同注量的多能氦离子注入和注氦后不同温度退火的多晶W中He相关缺陷的演化机制。结果表明，W材料中由多能氦离子注入引入的空位型缺陷数目随着He＋注量的升高而增大；220℃退火引起注氦W样品中的间隙W原子与空位的复合，降低了材料中的空位型缺陷数目；450℃和650℃退火的注氦W材料中形成了He泡，He泡尺寸与退火温度有关，650℃退火的样品中观测到直径达600nm的大尺寸He泡和孔洞结构。

英文摘要：

Tungsten is considered as the most promising candidate for plasma-facing materials in fu- ture nuclear fusion reactors. The damage behaviors of tungsten under different He irradiation are one of the main issue of concerns. In this work, the evolution of helium-related defect in polycrystalline tungsten was studied by slow positron beam analysis （SPBA） and SEM as functions of annealing temperature and implantation fluence. The results show that the number of vacancy-type defect induced by the multi-energy He irradiation increases with the increment of irradiation fluence. At the meantime, annealing at the tem- perature of 220 ℃ induces the recombination of interstitial W atoms with vacancies, thus reduces the number of the vacancy-type defects in the sample. And annealing at 450 and 650 ℃ leads to the forma- tion of He bubbles in the tungsten materials, and the size of He bubbles in tungsten is related to the an- nealing temperature, and the He bubbles and holes with a diameter of about 600 nm could be observed for the specimen annealing at 650 ℃.