Arrangement and method for improving vacuum in a very high vacuum system

A method of applying a layer having a getter function adapted to generating, due to a getter effect, a vacuum in a chamber defined by a metal wall which possibly may release gas at its surface, said layer having a getter function being deposited on at least almost the whole surface of the chamber wall, wherein:

• at least a thin layer of non-evaporable getter is deposited, by cathode sputtering, on at least almost the whole surface of the chamber wall, said getter being adapted to absorb hydrogen and isotopes thereof and being selected from titanium and/or zirconium and/or hafnium and/or vanadium and/or scandium and/or an alloy or metal compound including at least one of these;
• then at least a thin layer of at least a catalyst is deposited, by cathode sputtering, on said non-evaporable getter layer, said catalyst being selected from ruthenium and/or rhodium and/or palladium and/or osmium and/or iridium and/or platinum and/or an alloy including at least one of these;
• the electrode used for the cathode sputtering being removed after the end of the layer deposition;
• the vacuum chamber is assembled;
• and
• vacuum is generated with a pumping system;
• whereby said layer stops gas released by the chamber wall, on one hand, and pumps hydrogen and isotopes thereof present in the chamber when vacuum is generated, on another hand.