Fundamental Processes of Beam-Particle and Surface Interaction for the Study of Particle Recycling mechanizm on a Diverter

在聚变装置中，限制器和转向器材料的表面被电子、离子、α粒子和中性粒子连续轰击。这些表面会随时间发生变化，并且与干净的材料表面不同。高能粒子的表面相互作用，如反射、溅射、解吸等，不仅对面向等离子体的部件而且对等离子体性能都起重要作用。偏滤器板上的表面相互作用是壁寿命和散热方面的主要问题之一，这些问题从根本上与来自偏滤器壁的粒子再循环和等离子体-表面相互作用有关。高Z材料，例如钼或钨，现在从这些方面吸引了人们的注意，但是它们的复合表面或在真空容器中覆盖有其他材料（例如碳）的表面的性质还没有得到足够的研究。我们建立了一套系统地研究低能束流与材料相互作用的实验系统。本文测量了低能（0.5 - 3keV）氢、H ^+、H_2 ^+、H ^O离子束和中性粒子束轰击钼和碳蒸镀钼表面反射的正、负离子的角分布和能谱。氢分子离子轰击产生的角分布、能谱和正负离子比。与质子以相同速度入射时的结果几乎相等。在大多数情况下，来自碳蒸发表面的负离子分数被抑制，特别是在轰击开始时。

In fusion devices, surfaces of limiter and diverter materials are continuously bombarded by electrons, ions, alpha particles, and neutral particles. These surfaces are changing time-to-time, and different from a clean material surface. Surface interactions of energetic particles, such as reflection, sputtering, desorption, etc., play significant roles not only for the plasma facing components but also for the plasma performance. The surface interactions on divertor plates are one of the major concerns in the aspects of the wall life time and heat removal, and these issues are fundamentally connected to the particle recycling from the diverter wall and the plasma-surface interaction in. High-Z materials, such as molybdenum or Tungsten are now attracting attention from these aspects, but the property of their-composite surfaces, or surfaces with coverage of other materials in the vacuum vessel, such as carbon, has not yet been studied enough. We have developed an experimental system to study low energy beam interaction with materials systematically. The angular distributions and energy spectra of reflected positive and negative ions from molybdenum and carbon-evaporated molybdenum surfaces bombarded by low energy (0.5-3 keV) ion-and neutral -particle-beams of hydrogen, H^+,H_2^+,H^O are measured. The angular distributions, energy spectra and the ratio of negative to positive ions due to molecular hydrogen ions bombardment. are nearly equal to those due to proton incidence of same velocity. The negative ion fraction from a carbon-evaporated surface is suppressed in most of cases, especially in the beginning of the bombardment.