COOLVAC vacuum pumps are gas entrapment cryo pumps where gaseous substances are bound to the cold surfaces within the pump by means of cryocondensation, cryosorption or cryotrapping. For that purpose the cold surfaces (cryopanels) must be cooled to a sufficiently low temperature. The COOLVAC pumps are cooled by two-stage cold heads of the COOLPOWER series using the Gifford/McMahon principle. COOLVAC pumps produce a hydro carbon free ultra high vacuum in the pressure range from 10^-3mbar to 10^-11 mbar (0.75•10^-3 to 0.75•10^-11Torr).