Development of copper electroformed vacuum chambers with integrated non-evaporable getter thin film coatings

Abstract

First results concerning a new approach of TiZrV non-evaporable getter (NEG) thin films coating on very small diameter vacuum chambers are presented. This new process is based on the electroforming of a vacuum chamber around a sacrificial mandrel, which is precoated with a NEG thin film. Aluminum was selected as the material of the mandrel and magnetron sputtering deposition for the coating. To improve the quality of the NEG coating, different coating layer sequences were applied and tested. The NEG activation was characterized by x-ray photoelectron spectroscopy (XPS). Data from flat samples prepared with the new technique were compared with those produced by the common magnetron sputtering method. Afterward, vacuum chambers equipped with flanges were produced. In addition to the XPS characterization, pumping speed measurements were performed. The results show CO pumping speeds comparable with the ones measured on a standard NEG coated vacuum chamber. However, H2 pumping speed exhibits ten times lower values than expected for standard NEG.