Abstract
Low temperature pumping is utilized to achieve pressures as low as 10−11 Torr. In the first method, the entire sample chamber is immersed inside liquid helium. The second method, which is more economical than the first one, combines a large capacity titanium sublimation pump and a small cold trap immersed inside a liquid‐helium storage Dewar. The ultrahigh vacuum system described here is economically competitive with the best ion‐pumped vacuum system available today.
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