DECREASING SURFACE OUTGASSING BY THIN-FILM GETTER COATINGS

The UHV behaviour of stainless steel vacuum chambers, coated ex situ b y sputtering with a thin film of a getter material, has been investiga ted. The purpose of this study was to ascertain if the getter film cou ld be activated after air exposure by in situ baking, so as to transfo rm the vacuum chamber from a gas source into a pump. Many elements and alloys have been tested all of which could be activated by baking at temperatures acceptable for stainless steel components, i.e. lower tha n 400 degrees C. In one case (equiatomic TiZr alloy) an activation tem perature of 200-250 degrees C has been measured. This investigation ha s been carried out using Electron Stimulated Desorption, pumping speed and ultimate pressure measurements. (C) 1998 Elsevier Science Ltd. Al l rights reserved.