Treatment of the wall materials of extremely high vacuum chamber for dynamical surface analysis

In order to investigate the surface structure dynamically reducing the influence of the residential molecules upon the surface, the way to observe the surfaces under the extremely high vacuum (XHV; <10−12 Torr) condition has been discussed. We proposed to combine the two processes, electrochemically polishing and high temperature baking, in order to reduce the outgassing rate of the wall material. We have characterized the inner surfaces of the stainless steel chamber processed by two optimum ways to minimize outgassing rate, by means of surface analysis and measurements of gas emission rate. We have found that in order to accomplish the XHV condition, the inner surface should be electrochemically polished after the complete baking of the material itself at 1300 K. These processes made the degassing rate of the wall lowest.