초록 ▼

A cryopump having at least two temperature stages for pumping gases at their optimal temperatures. A first embodiment has a third temperature stage that is surrounded by and separated from the second temperature stage which is surrounded by and separated from the first temperature stage. Adsorbent p

A cryopump having at least two temperature stages for pumping gases at their optimal temperatures. A first embodiment has a third temperature stage that is surrounded by and separated from the second temperature stage which is surrounded by and separated from the first temperature stage. Adsorbent placed on the second and third stages are operated at different temperatures to prevent gases with higher critical mobility temperatures from becoming immobilized at the entrance of pores and wells along the surface of the adsorbent. Another embodiment has at least a second stage, a temperature sensor, and a heater to maintain the second stage temperature at optimal level for the gas being pumped.

대표청구항 ▼

A cryopump having a pumping operation and a regeneration cycle and comprising a first temperature stage having a first pumping surface for condensing gases, a second temperature stage having a second pumping surface with a first adsorbent thereon, the second stage being cooled to a lower temperature

A cryopump having a pumping operation and a regeneration cycle and comprising a first temperature stage having a first pumping surface for condensing gases, a second temperature stage having a second pumping surface with a first adsorbent thereon, the second stage being cooled to a lower temperature than the first temperature stage for pumping gases not pumped by the first pumping surface, and a third temperature stage having a second adsorbent surface and a temperature control system having a heating element in thermally conductive contact with the second temperature stage to maintain the temperature of the second stage above a minimum temperature below which the capacity of the first adsorbent, in pumping the gas to be pumped by the first adsorbent during the pumping operation, is substantially reduced.