High conductance cryopump for type iii gas pumping

Abstract

A cryopump provides for high pumping speed of Type III gases. An open configuration of a frontal array provides high conductance of gases into a radiation shield which is shaped to focus gases toward a second stage array. The second stage array has an open configuration of baffles coated with adsorbent. Substantially all of the adsorbent has a direct line of sight to the radiation shield or to the opening in the radiation shield, and substantially all of the baffles are coated with adsorbent. In one form, the second stage cryopump array comprises an array of discs fanned to define a generally ball shaped envelope.

Description

[0001] related application [0002] This application is a continuation of, and claims the benefit of, US Application Serial No. 10 / 948,955, filed September 24, 2004. The entire teaching of this application is hereby incorporated by reference herein. Background technique [0003] Currently available cryopumps, whether open to refrigerate or closed to refrigerate, generally follow the same design philosophy. A cryogenic second stage array, typically operating in the 4-25 degree Kelvin range, is the primary pumping surface. This surface is surrounded by a high temperature cylinder, typically operating in the temperature range of 40-130 degrees Kelvin, which provides radiation shielding for the lower temperature array. Said radiation shielding generally comprises an enclosure which is closed except for the front array between the main suction surface and the chamber to be evacuated. This higher temperature, first stage, front array all act as pumping locations for higher boilin...

AI Technical Summary

Problems solved by technology

For example, U.S. Patent No. 4,718,241, which is hereby incorporated by reference herein, describes a design that increases the rate at which noncondensable gases are pumped, while at the same time limiting the frequency of renewal of the system

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