Ebara Technologies Incorporated

Mark O Foreman

Johan E De Rijke

Huruli D Kishorenath

Apparatus and method for vacuum pumping an enclosed chamber includes a cryogenic pumping device in fluid communication with the chamber for removing gases from the chamber. The cryogenic pumping device includes a cooled pumping surface and an expander for expanding a compressed gas and thereby cooling the pumping surface. The vacuum pumping apparatus further includes a sensor for sensing an operating parameter, such as temperature, of the cryogenic pumping device and a controller responsive to the sensor for controlling the operating speed of the expander to produce a desired value of the operating parameter. Typically, the sensor is a temperature sensor, and the controller controls the speed of the expander motor.

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Stockton, CA, United States of America

Mark O Foreman