Latest developments in ion pump technology: the NEG ion pump

Abstract

The combination of ion pumps and NEG (Non Evaporable Getter) films is a well known and widely use pumping method to reach UHV in large vacuum systems such as particle accelerators and synchrotron light sources. The latest development in Ion pump technology is the NEG Ion Pump. The body of such Ion Pump is internally coated by a TiZrV getter thin film. TiZrV is a well-known alloy able to pump getterable gases such as hydrogen, oxygen, nitrogen, carbon monoxide and carbon dioxide. As a result, the net pumping speed of this pump is an order of magnitude higher when compared to conventional ion pumps. However, with the exception of hydrogen, the sorption of these gases is not reversible; this causes a progressive saturation of the material, resulting in a reduced pumping effect. The deposition of an additional Palladium layer, while limiting the pumping effect to hydrogen and carbon monoxide only, dramatically increases the lifetime of the getter film, allowing a large number of thermal activations, which restore the initial performances of the film. The performance of such innovative ion pump design are presented and discussed. Laboratory test results on ultimate pressure, pumping speed measurements, and reactivation procedure are reported.