Clean ultrahigh vacuum system with single-structure diffusion pumps

Authors

Timothy J. Gay, University of Nebraska - LincolnFollow
M.C. Fritts, University of Missouri-Rolla, Rolla, Missouri
J.E. Furst, University of Missouri-Rolla, Rolla, Missouri
M.A. Khakoo, University of Missouri-Rolla, Rolla, Missouri
E.R. Mell, University of Missouri-Rolla, Rolla, Missouri
M.T. Seiger, University of Missouri-Rolla, Rolla, Missouri
M.W.K.P. Wijayaratna, University of Missouri-Rolla, Rolla, Missouri

Date of this Version

September 1994

Comments

Published in J. Vac. Sci. Technol. A 12(5), Sep/Oct. 1994. Copyright 1994 American Vacuum Society. Used by permission.

Abstract

A practical example of the use of single-structure diffusion pumping groups in an experiment requiring hydrocarbon-free, ultrahigh vacuum is presented. With the use of proper vacuum procedures and careful foreline design and operation, but with no exotic hardware or liquid nitrogen, we have demonstrated that such a pump could provide vacuum that was "clean," i.e., which had no residual pump-oil contamination to a partial pressure below 10-8 mbar. Their use is thus compatible, at least in peripheral vacuum chambers, with standard "UHV-surface science" processes. We discuss our vacuum system in detail, and present a review of the literature on the production of clean vacua with diffusion pumps.