 Pumping intermittently high quantities of hydrogen with noble diodes should be done with great care, as hydrogen might over months get re-emitted out of the tantalum.Ion pumps are commonly used in ultra-high vacuum (UHV) systems, as they can attain ultimate pressures less than 10−11 mbar.In contrast to other common UHV pumps, such as turbomolecular pumps and diffusion pumps, ion pumps have no moving parts and use no oil.