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Reproducibility of the Accommodation Coefficient of the Spinning Rotor Gauge



Ren F. Chang, Patrick J. Abbott


Eight spinning rotor gauges were calibrated numerous times simultaneously with the primary midrange vacuum standard at the National Institute of Standards and Technology, over a period of fifteen months to assess the reproducibility of their accommodation coefficients. Events encountered by a rotor during its normal operations are investigated for their effects on the accommodation coefficient of the rotor. The effects of baking as well as crashing of the rotors are also investigated. We found that the accommodation coefficient can be dependent on the orientation of the rotor s suspension probably due to rotor blemishes that are not isotropic. Consequently, the accommodation coefficient will not reproduce well when the rotor is re-suspended because the rotational axis is not replicated. Data on the accommodation coefficient obtained from ordinary rotors as well as rotors specifically prepared with a band of scratches to exaggerate the non-isotropic nature of the blemishes will be presented.
Journal of Vacuum Science and Technology A


accommodation coefficient, calibration, reporducibility, spinning rotor gauge


Chang, R. and Abbott, P. (2007), Reproducibility of the Accommodation Coefficient of the Spinning Rotor Gauge, Journal of Vacuum Science and Technology A, [online], (Accessed July 22, 2024)


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Created October 1, 2007, Updated November 10, 2018