AVS 47th International Symposium
    Vacuum Technology Wednesday Sessions
       Session VT-WeA

Paper VT-WeA3
A Quantitative Test of Slip-Flow Theory using the Spinning Rotor Gauge

Wednesday, October 4, 2000, 2:40 pm, Room 201

Session: Vacuum Gas Dynamics
Presenter: J.P. Looney, National Institute of Standards and Technology
Authors: J.P. Looney, National Institute of Standards and Technology
J. Setina, Institute of Metals, Slovenia
Correspondent: Click to Email
Although a theory for gas slip flow has been in existence from the time of James Maxwell, no quantitative test of slip flow theory has been undertaken. Typically the slip flow theory of Maxwell is used to extract momentum accommodation coefficients from gas flow data. This is one method for 'measurement' of gas accommodation coefficients. However, this assumes that slip-flow theory is correct and that there is indeed proportionality between the magnitude of the momentum accommodation at the surface and the gas 'slip'. No test of this conjecture has been reported to the author's knowledge. In this talk I will report on the simultaneous and independent measurement of gas momentum accommodation and gas slip coefficients for a group of six spinning chrome steel spheres (spinning rotor gauges) and for four gases (H2, He, N2, and Ar). The results of these experiments clearly demonstrate the proportionality between the gas slip and momentum accommodation. A detailed comparison of these measurments with slip-flow theory will be made.