Cryopump

摘要

A cryopump is provided with a detecting means (35) for detecting an operation parameter at an elapsed operation time in a current operation cycle of the cryopump, a storing means (53) for storing a value of another operation parameter in a past operation cycle of the cryopump as a management parameter, an arithmetic controlling means (51) for calculating a succeeding rotational speed of the expander motor (40) based on the current operational parameter and the management parameter stored in the storing means and outputting the same as a driving instruction signal, with which the succeeding rotational speed of the expander motor (40) is controlled so as to maintain a temperature of a cryopanel (12) or a pressure in a vacuum chamber (100) to which the cryopump is attached at a predetermined value by using the operation parameter at the elapsed operation time in the current operation cycle of the cryopump detected by the detecting means and the operation parameter at the corresponding elapsed operation time in the past operation cycle of the cryopump stored in the storing means (53) as the management parameter, and an expander motor (40) driving means for driving the expander motor (40) according to the driving instruction signal output from the arithmetic controlling means (51), whereby the cryopump may be operated stably even if a temporal load change has occurred.