Achievement of extremely high vacuum in an electrolytically polished stainless steel vacuum chamber

In order to lower the ultimate pressure of a vacuum chamber, it is necessary to reduce the outgassing rate from the chamber and to improve the pumping ability. To reduce the outgassing rate, the chamber surface was treated by electrolytic polishing. The pumping speed was improved by a reduction of gases dissolved in a filament of a titanium sublimation pump. We succeeded in achieving extremely high vacuum (XHV) of the order of 10−11 Pa from atmospheric pressure within one day. XHV without baking was also achieved.