Editing Cryopump (section)

===Regeneration===
Regeneration of a cryopump is the process of evaporating the trapped gases. During a regeneration cycle, the cryopump is warmed to room temperature or higher, allowing trapped gases to change from a solid state to a gaseous state and thereby be released from the cryopump through a pressure relief valve into the atmosphere.

Most production equipment utilizing a cryopump have a means to isolate the cryopump from the vacuum chamber so regeneration takes place without exposing the vacuum system to released gasses such as water vapor. Water vapor is the hardest natural element to remove from vacuum chamber walls upon exposure to the atmosphere due to monolayer formation and hydrogen bonding. Adding heat to the dry nitrogen purge-gas will speed the warm-up and reduce the regeneration time.

When regeneration is complete, the cryopump will be roughed to 50μm (50 milliTorr or {{not a typo|μmHg}}), isolated, and the rate-of-rise (ROR) will be monitored to test for complete regeneration. If the ROR exceeds 10μm/min the cryopump will require additional purge time.