| 摘要 |
PURPOSE:To increase the pump exhaust speed and exhaust capacity by exhausting hydrogen and neon gases under a cold condition generated by the Joule- Thomson effect of the helium gas pre-cooled by a helium refrigerator and eliminating a discharge from an adsorbing material. CONSTITUTION:In the first cryopanel 23 cooled to a temperature of about 70K by the heat contact with the first heat station 6 of a helium refrigerator 2, vapor and carbon dioxide gases are condensed and discharged; and in the second cryopanel 24 cooled to a temperature of about 20K by the heat contact with the second heat station 7 of the refrigerator 2, nitrogen, oxygen and argon gases are condensed and discharged. Only hydrogen, neon and helium gases remain under this condition, and these gases are basically condensed and discharged by the third cryopanel 25 cooled to an extremely low temperature of about 4-10K. Accordingly, the gas exhaust speed and exhaust capacity can be increased as compared with a case in which all these gases are adsorbed and discharged.
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