A cryopump having a cryopump chamber includes a purge gas valve coupled to the cryopump chamber for supplying a first quantity of warm gas to the cryopump chamber in order to purge the cryopump chamber during regeneration. A roughing valve couples the cryopump chamber to a roughing pump enabling the cryopump chamber to be roughed. An exhaust valve is coupled to the cryopump chamber for exhausting gases from the cryopump chamber during purge. A delivery valve is coupled to the exhaust valve for delivering a second quantity of warm gas directly onto surfaces of the exhaust valve for warming the surfaces of the exhaust valve.

The cryopanel of a cryopump can be preferentially defrosted to remove an acid-forming or toxic gas while leaving a second gas substantially condensed upon the cryopanel thereby limiting interaction between the vapor phases of the two gases. The cryopanel is warmed to a temperature within a selective defrost range at which the first gas selectively sublimates from the cryopanel. The temperature of the cryopanel is then maintained at a temperature within this range until the cryopanel is substantially cleared of the first gas leaving the second gas substantially undisturbed as a condensate upon the cryopanel. In a preferred embodiment, the cryopanel is maintained at about 50 to 85K during standard operation before being defrosted.

A method for regulating the cooldown of multiple cryogenic refrigerators supplied with compressed refrigerant from a common compressor includes the following steps. The cooldown of the refrigerators is monitored. The cooldown of at least one refrigerator is then governed to regulate the gas flow distributed from the compressor to each of the refrigerators to enhance the cooldown of an individual refrigerator. Governing a refrigerator to achieve the objectives of this method can be achieved by various processes. These processes include supplying heat to the refrigerator, slowing the speed of the displacer in the refrigerator, halting the motion of the displacer, and profiling the speed of the displacer as a function of the first and second-stage temperatures. A system for performing the above-described method includes a compressor; a plurality of refrigerators, each receiving compressed gas from the compressor; and a network terminal programmed to govern the cooldown of at least one refrigerator to accelerate the cooldown of another refrigerator.