Patent ID: 6155059
Filing Date: 2000-12-05
Classification: F04B

Abstract:
A cryopump comprising:a radiation shield having an interior surrounded by at least one wall, the radiation shield having an opening through which gases are cryopumped into the interior;a frontal cryopanel array positioned near the opening for condensing high boiling point gases, the radiation shield and frontal cryopanel array being cooled to a first temperature;first primary cryopanel surfaces extending near the wall within the interior of the radiation shield and cooled to a second temperature below the first temperature for condensing low boiling point gases near the wall of the radiation shield while leaving a central gas flow pathway from the opening past the first primary cryopanel surfaces; andsecond primary cryopanel surfaces positioned within the interior of the radiation shield and cooled to about the second temperature including adsorbent for adsorbing very low boiling point gases, the first primary cryopanel surfaces limiting 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.