Method and apparatus for rejuvenating ion sources

The performance of mass spectrometer ion sources deteriorates with use because of the buildup of electrically insulating deposits within the ionizing chamber due to the reactions between the charged particles and other materials in the chamber. A similar problem arises in the mass analyzer part of the spectrometer. The ion source can be rejuvenated by introducing an ionizing gas, preferably argon, into the source, replacing the anode with one made of gold or other sputtering metal, ionizing the gas, and applying a negative potential to the anode, causing it to be bombarded with ions to sputter metal onto the the interior of the source. In another aspect, the ion source is part of a mass analyzer. A filament or container of metal to be evaporated is provided with means to evaporate the metal so as to coat the ion deflecting elements with metal