Development of a 20-inch Cryopump and Reliability Test on a GM Cryocooler

This research paper handles fabrication and testing issues during localization of a 20-inch cryopump. The developed cryopump is equipped with a two-stage GM (Gifford- McMahon) cryocooler. The GM cryocooler can absorb heat of 80.21 W and 8.05 W at each stage under the temperature of 69.59 K and 17.98 K, respectively. At this time, The electric consumption is recorded to be 5.77 kW. Reliability test on the GM cryocooler is also being conducted to secure track-record in commercializing the developed cryopump (currently 6,500 hours passed). For the cryopump, using nitrogen gas, the ultimate pressure and pumping speed are measured to be 9.07×10SUP-9/SUP mbar and 11,473 L/s.