Ion Getter Pump

A pump with no moving parts, no oil, and no exhaust — it buries the gas inside itself forever.

Maintains ultra-high vacuum (UHV) in sealed chambers — from particle accelerators and surface-science instruments to satellite ion thrusters and quantum computers — by continuously removing residual gas without any mechanical moving parts, oil, or cryogen. Once switched on and handed a pressure below about 10⁻⁴ mbar, it can hold a chamber at 10⁻¹¹ mbar essentially indefinitely.

Inside the pump, an array of short cylindrical anode cells sits between two flat titanium cathode plates, all immersed in a permanent magnetic field of roughly 0.1–0.2 T. A high voltage of 3–7 kV is applied to the anodes. Stray electrons spiral into helical orbits along the magnetic field lines — a Penning discharge — and collide with residual gas molecules, ionising them. The resulting positive ions accelerate toward the grounded titanium cathodes at high energy, doing two things simultaneously: they implant themselves physically into the titanium (pumping noble gases such as argon), and they sputter fresh titanium atoms onto surrounding surfaces. That freshly deposited titanium film is highly chemically reactive, chemisorbing active gases like nitrogen, oxygen, hydrogen, carbon monoxide, and water vapour on contact. Both mechanisms permanently remove gas from the chamber with no exhaust path.

In plain terms

Imagine a vacuum cleaner that, instead of a bag, melts the dust into the walls so it can never come back out. That's what an ion getter pump does to air molecules — it zaps them, flings them at a metal plate, and the metal swallows them permanently.

Also called: sputter ion pump, SIP, VacIon pump, ion pump.

Why it matters

Where it lives

Key numbers

Surprising facts

A short history

The sputter ion pump was invented at Varian Associates in Silicon Valley. Robert Jepsen, Lewis Hall, and John Helmer filed the foundational patent in 1957, initially to maintain UHV inside microwave klystron tubes after processing. The pump leveraged the Penning discharge — a plasma confinement geometry described by Frans Penning in the 1930s — and replaced the titanium Penning gauge cathode with a thick, long-lived getter target. By 1960 Varian was selling commercial units with honeycomb anodes and pumping speeds in the thousands of litres per second. The triode geometry (W. Brubaker, Consolidated Electrodynamics, 1960) solved the argon-instability problem of diode pumps for noble-gas environments. In 1983 Varian introduced the StarCell cathode structure — titanium fins arranged radially — which achieved the longest cathode life and best noble-gas pumping of any diode geometry. Agilent Technologies acquired Varian's vacuum division in 2010 and continues to manufacture the VacIon Plus family.

Sources

Related