Comparison of an ultrasonic interferometer manometer and a new dynamic flow control system in the pressure range 1–133 Pa

Abstract

This work is concerned with comparison of two low-pressure calibration systems at the Korea Research Institute of Standards and Science (KRISS). The ultrasonic interferometer manometer (UIM) which is a national primary standard and the dynamic flow control system (FCS) which can be used for the calibration of vacuum gauges by comparison method by generating precise and stable pressure in the range 1–133 Pa. For this comparison, a capacitance diaphragm gauge (CDG) of 133 Pa full-scale range was used as transfer standard in the overlapping range of 1–133 Pa. The behavior of two systems in the pressure range 1.37–11.5 Pa had large variations which gradually reduced above 11.5 Pa. In the range 1.37–11.5 Pa, the difference in calibration factors for the two systems was 0.0114 with relative deviations of 5.177%. However above 11.5 Pa the corresponding values were 0.0056 and 1.197%, respectively. Since in vacuum metrology, UIM is world-wide recognized as a national calibration standard, the results of this comparison will be used to validate the FCS for calibration of low vacuum gauges.