AVS 46th International Symposium
    Vacuum Technology Division Tuesday Sessions
       Session VT-TuM

Paper VT-TuM2
The Use and Calibration of Spinning Rotor Gages at Non-Ambient Temperatures

Tuesday, October 26, 1999, 8:40 am, Room 610

Session: Total and Partial Pressure Gauging
Presenter: C.R. Tilford, National Institute of Standards and Technology
Authors: C.R. Tilford, National Institute of Standards and Technology
B. Lindeanau, FZJ-IGV, Germany
Correspondent: Click to Email
Many applications require accurate low pressure measurements at temperatures different from room temperature. These measurements are complicated by thermal transpiration effects and the thermal and chemical perturbations associated with most high vacuum gages. The use of an in situ spinning rotor gage (SRG) is a possible solution for such problems. The SRG is stable, inert, and its power disappation is in the milliwatt range. However, for the most accurate measurements it must be determined if the effective accomodation coefficient, the factor determining the sensitivity of the SRG, is temperature dependent. This talk describes the design and performance of a calibration system that corrects for thermal transpiration effects and allows the in situ calibration of SRGs for temperatures between 77 K and 400 K. This system has been used to investigate the temperature dependence of the effective accomodation coefficients for both "smooth" and deliberately roughened steel balls used as SRG rotors.