Design and pumping characteristics of a compact titanium–vanadium non-evaporable getter pump

Abstract

A compact non-evaporable getter (NEG) pump is made by stacking sintered titanium–vanadium blades recently available from SAES Getters as St185. The 50 blades are stacked between copper spacers on a stainless steel tube, and are activated by a removable heater cartridge inserted into the tube. The room temperature pumping speeds for CO and N2 are measured as a function of sorbed gas quantities at various activation temperatures and with different NEG disk spacing, in order to optimize the pump design and operation. The study shows that there is a threshold of activation at a temperature of about 340 °C and optimal pumping speed and pumping capacity can be achieved with activation temperature around 550 °C. Linear pumping speeds of about 2200 l/s m and 1300 l/s m can be achieved for CO and N2, respectively, with activation at temperatures of 500 °C for 1 h. A direct comparison shows a much higher pumping speed for the St185 than that for the St707 (Zr–V–Fe alloy, also by SAES Getters). The low activation temperature of the St185 NEG and the compact design make the NEG pump cartridge particularly attractive for situations with tight space and with components sensitive to high temperature.