Accuracy of vacuum gauges

Abstract

The performance characteristics of the following types of vacuum gauges are discussed: quartz Bourdon gauge (QBG), capacitance diaphragm gauge (CDG), thermal conductivity gauge (TCG), quartz friction gauge (QFG), spinning rotor gauge (SRG), cold cathode ionization gauge (CCG), hot filament ionization manometer (IM), quadrupole mass spectrometer (QMS) and other mass spectrometers. Depending on the pressure, the most stable gauges are the QBG, the CDG, the SRG, and the IM. In applications with modest demands on the measuring accuracy, it may be sufficient to employ an uncalibrated gauge and adopt an average gauge coefficient given by the manufacturer. In cases with higher demands on the accuracy, the calibration of individual gauges may be necessary. The highest demand arises if the gauges are used as transfer standards in intercomparisons of primary pressure standards. Here, the achievable accuracy is limited by the stability of the gauge with time. Gauges based on different operating principles and different constructions show different stabilities. Furthermore, the stability depends on the handling of the gauge. This paper compiles available data on the accuracy performance of the various gauges.