High capacity cryopump

摘要

A cryopump including a radiation shield having an interior surrounded by at least one wall. The radiation shield has an opening through which gases are cryopumped into the interior. A frontal cryopanel array is positioned near the opening for condensing high boiling point gases. The radiation shield and frontal cryopanel array are cooled to a first temperature. First primary cryopanel surfaces extend near the wall within the interior of the radiation shield and are cooled to a second temperature below the first temperature for condensing low boiling point gases near the wall while leaving a central gas flow pathway from the opening past the first primary cryopanel surfaces. Second primary cryopanel surfaces cooled to about the second temperature are positioned within the interior of the radiation shield and include adsorbent for adsorbing very low boiling point gases. The first primary cryopanel surfaces limit the amount of low boiling point gases condensing on the second primary cryopanel surfaces while leaving open the central gas flow pathway to the second primary cryopanel surfaces.