| 摘要 |
PURPOSE:To make it possible to perform the calibration and capacity measurement of a vacuum gauge in a pressure region lower than 10<-4>Torr with good accuracy, by correlating the hydrogen transmissivity of a nickel membrane with the temp. dependency of hydrogen transmissivity. CONSTITUTION:A current is supplied to a heater 16 to adjust the temp. T of a nickel membrane to predetermined one and, after said temp. T reached the predetermined one, the opening degree of a flow control valve 17 is regulated to allow the pressure of the calibration gas in a heating chamber to reach predetermined one on the basis of the indication of a pressure gauge 38 and, thereafter, a flow control valve 17 is closed and the flow control valve 18 and check valve 19 in the side of a vacuum chamber 17 are perfectly closed. Next, the hydrogen partial pressure P1 of the calibration gas in the heating chamber is calculated by a static equilibrium method and the calibration of a high pressure gauge to be calibrated is subsequently performed. After preparation has been finished, the calibration of the high vacuum gauge 1 to be calibrated is performed. An ion pump 26 is started and the flow control valve 18 is opened to set the vacuum chamber 7 to a dynamic equilibrium state, that is, a state having the flow of gas. Next, when the temp. T of the nickel membrane is changed while the vacuum chamber is held to a dynamic state, calibration is enabled by the pressure P3 of the vacuum gauge part to be calibrated and the output of the high vacuum gauge 1 to be calibrated.
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