Abstract
Fast clean pumpdown to 10-7Torr range from high crossover pressure was a luxury a decade ago. Today the manufacturing/equipment engineer has at hand reliable, economical, and maintainable cryopumps alternative to conventional high vacuum pumps. This paper traces the nonliquid cryogen, mechanical refrigeration supported pump package from its inception to acceptance within IBM. © 1985, American Vacuum Society. All rights reserved.