HT-7托卡马克中锂第一壁研究的先行试验  

Bench Test of Lithium First Wall in HT-7 Tokamak

作　　者：左桂忠[1] 胡建生[1] 罗南昌[1] 李建刚[1] 张凌[1] 

机构地区：[1]中国科学院等离子体物理研究所,合肥230031

出　　处：《真空科学与技术学报》2010年第3期273-278,共6页Chinese Journal of Vacuum Science and Technology

基　　金：国家自然科学基金项目(No.10705030)部分支持

摘　　要：为了抑制等离子体杂质和减少粒子再循环,获得高品质的等离子体,HT-7超导托卡马克将进行锂限制器实验。为此需要在实验台上开展一些先行试验,以掌握锂材料操作的关键工艺;在加热和直流辉光放电下,借助光谱仪及膜厚仪得到温度与锂熔化、挥发、沉积之间的关系。实验表明在锂温度低于300℃的情况下,锂挥发不明显;从300℃到360℃,挥发速度逐渐加快;当锂温度高于370℃,锂挥发急剧增加。利用蒸发镀膜和直流辉光放电等离子体镀膜,在真空室壁沉积了约300nm的锂膜,装置真空明显改善,表明锂膜对各种气体有很强的吸附和抑制作用。实验表明锂是托卡马克装置第一壁的理想材料之一,可以用于抑制等离子体中杂质,降低氢同位素再循环,提高等离子体性能。采用锂作为HT-7限制器,有必要在安装过程中采用氩气保护,以避免锂的氧化,同时在实验期间应避免锂限制器温度过高,以防止锂的快速蒸发。The movable lithium limiter was proposed for the HT-7 superconducting Tokomak for the purpose of sup- pression of plasma impurities, reduction of particle recycling and perfonnance improvement of the plasma. The temperature dependence of its physical properties, such as melting, volatilization, and deposition as well as their interdependence was bench tested to optimize the operating conditions. The results show that the temperature strongly affects the melting, volatilization, and deposition of lithium, and that lithium films have strong gettering capability. For instance, at a temperature below 300℃ ,volatilization of Li is negligible, however, as the temperature rises up from 300℃ to 360℃, volatilization rate rapidly increases, peaking at 370℃. The 300 nm thick Li film, deposited by evaporation or by plasma discharge, considerably getters the vacuum system because of its strong surface absorption. We suggest that Ar protection and low temperature be necessary when lithium is used as the moveable limiter in HT-7 Tokomak.

关 键 词：锂材料 第一壁 等离子体 HT-7托卡马克 

分 类 号：TB741[一般工业技术—材料科学与工程]