Abstract: A method of monitoring the performance of a cryopump, the circuitry for monitoring the performance and the cryopump are disclosed. The method comprises: following completion of a regeneration cycle controlling said cryopump to perform a predetermined test routine for testing a performance of said cryopump under predetermined conditions; monitoring said cryopump during said predetermined test routine to collect data indicative of said performance of said cryopump; storing data collected during said monitoring.

Abstract: A flow restrictor for restricting a flow rate of gas flowing into a cryopump and the cryopump are disclosed. The flow restrictor is configured to be mounted in an inlet of the cryopump, the flow restrictor comprising: an inlet component for providing a gas flow path into the cryopump; a shielding plate mounted to at least partially obscure the gas flow path though the inlet component; and an intermediate component linking the shielding plate to the inlet component, the intermediate component comprising at least one aperture, the at least one aperture defining at least one gas flow path into the cryopump The shielding plate is configured to shield the gas flow path through the inlet component such that when mounted on the cryopump there is no direct line of sight path through the inlet component to a cryopanel within the cryopump.