Claims
- 1. A cryopump comprising:
- a two-stage cold finger refrigerator having a first stage and a second stage;
- a first temperature stage having a first extended cryopanel pumping surface for condensing gases which are cooled by the first stage of the refrigerator;
- a second temperature stage having a second extended cryopanel pumping surface which is cooled to a lower temperature than the first temperature stage by the second stage of the refrigerator for pumping gases not pumped by the first pumping surface; and
- a third temperature stage having a third pumping surface which is cooled to a lower temperature than the second temperature stage by the second stage of the refrigerator for pumping gases not pumped by the second pumping surface.
- 2. A cryopump as claimed in claim 1 wherein:
- the first temperature stage is cooled to approximately 90.degree.-140.degree. K.;
- the second temperature stage is cooled to approximately 10.degree.-14.degree. K.; and
- the third temperature stage is cooled to approximately 5.degree. K.
- 3. A cryopump as claimed in claim 1 wherein:
- the second and third temperature stages are separated by a thermal insulator.
- 4. A cryopump as claimed in claim 1 wherein said cryopump is further comprised of a closed cycle refrigerator.
- 5. A cryopump comprising:
- a first temperature stage having a first extended cryopanel pumping surface for condensing gases;
- a second temperature stage having a second extended cryopanel pumping surface comprising a condensing surface for condensing lower condensation temperature gases not condensed on the first condensing surface and a first adsorbent surface for adsorbing gases having lower condensation temperatures not condensed on the second condensing surface; and
- a third temperature stage having a second adsorbent surface for pumping gases not adsorbed by the first adsorbent surface.
- 6. A cryopump as claimed in claim 5 wherein:
- the first temperature stage is cooled to approximately 90.degree.-140.degree. K.;
- the second temperature stage is cooled to approximately 10.degree.-14.degree. K.; and
- the third temperature stage is cooled to approximately 5.degree. K.
- 7. A cryopump as claimed in claim 5 wherein the third temperature stage is surrounded by and spaced from the second temperature stage, which is surrounded by and spaced from the first temperature stage.
- 8. A cryopump as claimed in claim 5 wherein:
- the second and third temperature stages are separated by a thermal insulator.
- 9. A cryopump as claimed in claim 5 wherein said cryopump is further comprised of a closed cycle refrigerator.
- 10. A cryopump having different temperature stages for pumping gases comprising:
- a two-stage cold finger, closed cycle refrigerator;
- a first temperature stage comprising a frontal array coupled to a radiation shield which is cooled by a first stage of the refrigerator;
- a second temperature stage comprising a primary pumping surface, surrounded by and separated from the radiation shield, comprising a condensing surface and an adsorbent cooled by a second stage, the coldest stage, of the refrigerator; and
- a third temperature stage surrounded by and separated from the second temperature stage comprising an adsorbent in thermal communication with the second stage of the refrigerator for adsorbing gases having very low boiling point temperatures.
- 11. A cryopump as claimed in claim 10 wherein:
- the first temperature stage is cooled to approximately 90.degree.-140.degree. K.;
- the second temperature stage is cooled to approximately 10.degree.-14.degree. K.; and
- the third temperature stage is cooled to approximately 5.degree. K.
- 12. A cryopump as claimed in claim 10 wherein:
- the second and third temperature stages are separated by a thermal insulator.
- 13. A cryopump comprising:
- a first adsorbing surface cooled to approximately 5.degree. K. for adsorbing gases having a very low critical mobility temperature;
- a second adsorbing surface cooled to approximately 10.degree.14.degree. K. for adsorbing gases having a higher critical mobility temperature than those gases adsorbed by the first adsorbing surface;
- a primary pumping surface cooled to approximately 10-14.degree. K. for condensing gas; and
- a secondary pumping surface cooled to approximately 90.degree.-140.degree. K. for condensing higher condensation temperature gases than those gases condensed on the primary pumping surface.
- 14. A cryopump as claimed in claim 13 further comprising a two-stage cold finger, closed cycle refrigerator, wherein the first stage of the cold finger is coupled to the secondary pumping surface, and the second stage of the cold finger, the coldest stage, is coupled to the primary pumping surface.
- 15. A cryopump as claimed in claim 14 wherein the first adsorbing surface is in thermal contact with the second stage of the cold finger and the second adsorbing surface is in thermal contact with the primary pumping surface.
- 16. A method of effectively adsorbing gases in a cryopump comprising the steps of:
- cooling a first temperature stage of the cryopump having a first condensing surface for condensing gases;
- cooling a second temperature stage of the cryopump having a second condensing surface and a first adsorbent surface for condensing and adsorbing lower condensation temperature gases than condensed on the first stage; and
- cooling a third temperature stage of the cryopump having a second adsorbent surface for adsorbing gases not adsorbed by the second stage.
- 17. A method of effectively adsorbing gases in a cryopump as claimed in claim 16 wherein:
- the first temperature stage is cooled to approximately 90.degree.-140.degree. K.;
- the second temperature stage is cooled to approximately 10.degree.-14.degree. K.; and
- the third temperature stage is cooled to approximately 5.degree. K.
Parent Case Info
This is a continuation of co-pending application Ser. No. 206,952 filed on June 8, 1988, now abandoned, which is a file-wrapper continuation of U.S. Ser. No. 007,320 filed on Jan. 27, 1987, now abandoned.
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Continuations (2)
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Number |
Date |
Country |
Parent |
206952 |
Jun 1988 |
|
Parent |
7370 |
Jan 1987 |
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