A pump that stores gas rather than exhausting it, using a two-stage helium refrigerator (the cold head) driven by a compressor. The first stage at about 50 to 80 K condenses water, the second stage at 10 to 20 K freezes nitrogen, oxygen and argon, and activated charcoal on the second stage adsorbs hydrogen, helium and neon. It gives very high water speed and a clean, oil-free vacuum, but it fills up and has to be regenerated.
Cryo's second stage is reading 18 K and climbing, she's full, schedule a regen tonight.
A cryopump releases everything it holds when it warms, which is why it carries a relief valve; never block the regen exhaust path.
Also heard as
- cryo
- cryogenic pump
Related terms
Regen
Clipped form of regeneration: warming a cryopump to drive off the gas it has captured, then cooling it again.
Crossover
Point in a pump-down where pumping switches from the roughing pump to the high vacuum pump.
Cold trap
Chilled surface in a pumping line that freezes out water and oil vapour before it reaches the chamber or the pump.
Getter
Reactive material that removes gas from a vacuum by binding it chemically to a fresh metal surface.