Performance characteristics of a multicelled, electrostatic, triode, getter-ion pump are described, with data on pumping speeds vs pressure for Ar,N2,O2, andH2, starting characteristics, pressure measurement, ultimate pressure, residual gas composition, and operating life. A 6-in.-diam orifice pump has a baffledN2pumping speed of over 1700 liter/sec below5 × 10−7Torr and pumps argon at 25 liter/sec. Pumping speeds higher than those predicted by the titanium sublimation rate are observed forN2,O2, andH2at pressures above10−6Torr. At10−3Torr, theN2speed is higher by a factor of 38. ForN2andO2, the higher than expected pumping speed is attributed to direct interaction of the gas with the sublimator, which operates at a temperature at which the interaction rate is maximal.