Vacuum pumping study of titanium-zirconium-vanadium thin films

Vacuum pumping via non-evaporable getter (NEG) thin film deposited directly onto the interior of a vacuum chamber is a novel way to achieve extreme high vacuum. As part of R&D efforts for the proposed Energy Recovery Linac at Cornell, the pumping performance of Titanium-Zirconium-Vanadium (TiZrV) NEG thin films was investigated to provide ´engineering´ data for designing vacuum systems using such NEG thin films. The compositions and growth rates of the NEG thin films, deposited on stainless steel tubes using DC Magnetron sputtering, were investigated using Rutherford Backscattering Spectrometry. The pumping speeds and capacities of the thin films for CO and H₂ were measured as functions of activation temperatures and durations, and film thickness. Though pumping of CO and H₂ by the NEG films is observed with activation temperatures as low as 150 °C, the pumping performance of the NEG films improves significantly with activation temperatures above 250 °C.