| AVS 55th International Symposium & Exhibition | |
| Vacuum Technology | Tuesday Sessions |
| Session VT-TuM |
| Session: | Vacuum Pumping Technologies, Large Vacuum Systems, Vacuum Modeling |
| Presenter: | D. Muller, Oerlikon Leybold Vacuum |
| Authors: | B. Rock, Oerlikon Leybold Vacuum D. Muller, Oerlikon Leybold Vacuum M. Ahlers, Oerlikon Leybold Vacuum T. Brown, Oerlikon Leybold Vacuum |
| Correspondent: | Click to Email |
Cryopumps have a higher effective pumping speed compared to ion pumps or turbomolecular pumps, especially for the typical gasses which limit the ultimate pressures in UHV devices like water vapor or Hydrogen. In addition, they are absolutely hydrocarbon free. The ultimate pressure of commercial refrigerator cooled cryopumps is mostly limited by 2 factors: they cannot be baked completely and they cannot be operated while attached to a chamber during bakeout due to the high thermal load. This paper presents a simple modification of a standard cryopump including the ability to cool the radiation shield with LN2 during bakeout. Pressures below 1 X 10-12 mbar have been reached even in larger vacuum chambers. The possibilities to measure these pressures via the Extractor gauge are shown too.