Attainment of Extremely High Vacuum Using Copper Ultrafine Powder as Cryosorbent in Bakeable-Type Cryopump

概要

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In order to obtain a clean extremely high vacuum, we made use of copper ultrafine powder (Cu UFP) as cryosorbent in bakeable-type cryopumps. Cu UFP was sintered on cryopanels and was cooled to temperatures less than 20 K to adsorb hydrogen. With use of the cryopumps, their cryopanels could be heated to the temperature of 200°C, which is effective for desorption of water from Cu UFP during regeneration. From studies on the pumping characteristics as a function of temperature, we found that the Cu UFP cryopanel at temperatures <20 K has sufficient pumping capacity for hydrogen released from a well-baked vacuum chamber. After successive bakeouts during regeneration and cryopumping, the test dome was evacuated to a pressure <10<SUP>-10</SUP> Pa which was maintained for several weeks.
日本真空協会の論文
1994-09-20