AVS 52nd International Symposium
    Vacuum Technology Wednesday Sessions
       Session VT-WeM

Paper VT-WeM8
The Hydrogen Pumping Speed of Sputter-Ion Pumps

Wednesday, November 2, 2005, 10:40 am, Room 201

Session: Gas Flow and Pump Technology
Presenter: K.M. Welch, Kimo M. Welch, Consultants
Authors: K.M. Welch, Kimo M. Welch, Consultants
S.P. Clough, Gamma Vacuum
Correspondent: Click to Email
It is difficult to find consistent quantitative data for the hydrogen speed of a conventional diode sputter-ion pump.  The reported numbers range from 80% to greater than 200% of the speed of the sputter-ion pump for nitrogen.  Reported numbers are in part obscured by conductance considerations when comparing speeds for the two gases.  For example, results of speed measurements on smaller pumps, with restricted input conductances, might yield higher relative hydrogen speeds than that observed with larger pumps.  Also, relative speed measurements are further obscured by pump conditioning prior to the measurements.  This paper first reviews the existing literature on reported hydrogen speeds of sputter-ion pumps for a variety of cathode materials.  Thereafter, results are reported on comparative speed measurements for the two gases in tests on a larger pump.  These data permit calculations of the actual intrinsic speeds of a unit-cell sputter-ion pump for the two gases., and therefore more reasonably predict expected speeds of multi-celled sputter-ion pumps.