Development of specular-reflecting wall by super-flattening process and its appliation to vacuum technology

本课题的主要目标是实现热能气体分子的镜面反射壁，而镜面反射壁加工的关键技术是实用壁材的超压平和超高真空条件下的无吸附表面清洗。在这个项目中，我们将我们的活动分为三个子主题(1)原子尺度平面的发展(2)用共振增强多光子电离技术（REMPI）测量漫射散射的偏差(3)用分子束技术直接测量散射分子的角分布。(1)原子尺度平面的发展我们主要研究了抛光Pt表面的平面化过程。用扫描隧道显微镜研究了离子轰击清洗后粗糙表面的扁化现象。确定了单原子高阶地形成的条件。应用共振多光子电离技术对超高真空环境中主要成分氢分子进行了检测。采用Nd-YAG激光器倍频产生紫外光，然后在BBO晶体中进行和频产生。最小检测限小于1*10^<-6> Pa。作为镜面反射的证明，我们尝试通过铂毛细管测量氢分子的角分布。目前，测量不成功的主要原因是真空系统没有足够的抽速。将对真空泵进行改进。(3)利用分子束技术直接测量散射分子的角分布筑波大学开发了分子束仪，并将其应用于修饰金属表面的角分布测量。证明了氦和氩的镜面反射具有很小的漫射散射分量。REMPI与分子束散射仪的结合正在发展中。少

The primaryaim of this project is to realize a specular reflecting wall for thermal energy gasmolecules The key technology to the processing of the specular reflecting wall is thought to be super-flattening of practical wall materials and adsorbate-free surface cleaning in ultrahigh vacuum condition.In the proiect, we divided our activity into three sub-themes(1) Development of flat surfaces in atomic scale(2) Measurement of deviations from diffuse scattering by using resonant enhanced multi-photon ionization technique (REMPI)(3) Direct measurement of angular distribution of scattered molecules by molecular beam technique.(1)Development of flat surfaces in atomic scaleWe mainly studied the flattening process of polished Pt surfaces. The flattening of rough surfaces after ion bombardment for the cleaing was studied by scanning tunneling microscope. The condition for the formation of monatomic-height terrace was determined.(2) Measurement of deviations from diffuse scattering by using re … More sonant multi-photon ionization techniqueWe applied resonant multiphoton ionization technique to the detection of hydrogen molecules which are the major constituent in ultrahigh vacuum environment. The ultraviolet light was generated by frequency doubling of Nd-YAG laser followed by sum-frequency generation in BBO crystal. The minimum detection limit was less than 1*10^<-6> Pa. As a proof for the specular reflection, we tried to measure angular distributions of hydrogen molecules through a Pt capillary. At present, the measurement was unsuccessful mainly due to the lack of sufficient pumping speeds in the vacuum system. The refinement of the vacuum pumps are going to be made.(3) Direct measurement of angular distribution of scattered molecules by molecular beam techniqueA molecular beam apparatus was developed in Tsukuba University and applied to the angular distribution measurement of modified metal surfaces. The specular reflection of Helium and Argon was demonstrated with very small diffuse scattering component. The combination of REMPI and molecular beam scattering apparatus is being developed. Less