Microstructural characterization of the Mixed-material deposition layer by using the advanced nano-fabrication technique

利用聚焦离子束(FIB)制备技术和透射电子显微镜(TEM)观察，对大型螺旋器件(LHD)第一壁(SUS316L)表面的微损伤、腐蚀和沉积进行了研究。第一壁表面的溅射侵蚀主要是由辉光放电清洗(GDC)引起的，而不是主要的等离子体放电，每个环形截面的侵蚀深度从50 nm到1000 nm不等。在不同的环形截面上，SUS316L基体上的沉积层特征和微观损伤是不同的。如果我们想要减少氢同位素在第一壁表面的滞留量，抑制混合物质沉积层的形成是必要的。

Toroidal profiles of the microscopic damage, erosion and deposition on the Large Helical Device (LHD) first-wall (SUS316L) were simultaneously evaluated by using focused ion beam (FIB) fabrication technique and transmission electron microscope (TEM) observation.Sputtering erosion of the first-wall surfaces was mainly caused by glow discharge cleanings (GDCs) and not main plasma discharges, and the erosion depths of each toroidal section were varied from 50 nm to 1000 nm. Characteristics of the deposition layers and microscopic damages on the SUS316L matrix were different in each toroidal section. If we would want to reduce the amount of the hydrogen isotope retention on the first-wall surface, suppression of the formation of the mixed-material deposition layer is necessary.