AVS 45th International Symposium
    Partial Pressure Measurements and Process Control Topical Conference Thursday Sessions
       Session PC-ThA

Paper PC-ThA10
Calibration of Gas-Analytic Mass Spectrometers for Gases and Vapors

Thursday, November 5, 1998, 5:00 pm, Room 317

Session: RGA Characteristics and Calibration
Presenter: R. Dobrozemsky, Vienna University of Technology, Austria
Authors: R. Dobrozemsky, Vienna University of Technology, Austria
G.W. Schwarzinger, Vienna University of Technology, Austria
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The demand to quantify pressure-, density-, and flow-rate-readings is steadily growing, e.g. for quality control. By many reasons, simple and reliable in-situ calibration methods for pressure-reading instruments (e.g. BA-gauges) and partial pressure analyzers (e.g. quadrupole mass spectrometers) are required. In this contribution, the potential of in-situ methods for calibration of vacuum instruments is discussed, with special attention on admitting gas bursts, defined by expansion of known quantities of gases and vapors. Ten years ago, a "gas-burst calibration" procedure for non-reactive gases has been introduced at Seibersdorf.@footnote 1@ Recent demands in geological research and space technology led to new calibration procedures for water- and oil-vapors (thermal decomposition method - TDM and crack-product calibration - CPC, respectively). By these methods, in-situ calibrations can be done with an accuracy of 1 to 3% for non-reactive gases (e.g. H@sub 2@, N@sub 2@, CO, CO@sub 2@, CH@sub 4@, He, Ar, etc.), of about 10% for water vapor and of about 20 to 40% for oil vapors. Moreover, calibrations can be repeated several times a day, if necessary (e.g. under harsh conditions), and ca be performed in a wide pressure range down to uhv. @FootnoteText@ @footnote 1@ R. Dobrozemsky, Vacuum 41, 2109 (1990)