Low profile cryopump

摘要

Faster cool down time is achieved in a low profile cryopump by having heat transferred directly from the inlet louver to the first stage heat station through one or more tapered thermal busses, and by obviating the need of a thermal shield over the second stage cylinder of the expander by having second stage cryopanels that form a nested tent like structure, at least one of which, extends over the cylinder.

主权项

1. A cryopump cooled by a GM type refrigerator, the cryopump comprising: a two-stage expander cylinder having a longitudinal cylinder axis laying in a first plane; an inlet for admitting cryogens, the inlet having a second plane parallel to the first plane; a first-stage cryopanel assembly attached to a first-stage heat station of the expander cylinder, the first-stage cryopanel assembly comprising: an inlet louver panel having a longitudinal panel axis laying in the second plane, the longitudinal panel axis being transverse to the longitudinal cylinder axis; and a second-stage cryopanel assembly attached to a second-stage heat station of the expander cylinder, the second-stage cryopanel assembly enclosed by the first-stage cryopanel assembly, the second-stage cryopanel assembly comprising a plurality of cryopanels, each cryopanel comprising a flat surface, at least one of the cryopanels being folded and extending over at least 90% of the second-stage cylinder of the expander cylinder; wherein heat is conducted from the inlet louver to the first-stage heat station through a thermal bus, the thermal bus being tapered over a length where the thermal bus is attached to the louver; and wherein a temperature gradient in a tapered section of the thermal bus is nearly constant.