Calibration of ultrahigh vacuum gauge from 10−9 Pa to 10−5 Pa by the two-stage flow-dividing system

A new two-stage flow-dividing system has been developed for the calibration of ultrahigh vacuum gauges from 10−9 Pa to 10−5 Pa for N2, Ar, and H2. This system is designed based on the techniques for our previously developed calibration system in the range from 10−7 Pa to 10−2 Pa. Three modifications were performed to extend the calibration pressure to a lower range. The relative standard uncertainty of the generated pressure (k = 1) is in the range from 2.3% to 2.6%, from 10−9 Pa to 10−5 Pa. The characteristics of ultrahigh vacuum gauges were also examined by using this system. The stabilities of the pressure reading, the linearity, the temperature dependence, and the long-term stability were examined. These results show that the calibration of ultrahigh vacuum gauges is possible in the range from 10−9 Pa to 10−5 Pa for N2, Ar, and H2 with the uncertainty of about 6.0% (k = 2) by this new system.

► Calibration system for ultrahigh vacuum gauges has been developed with the pressure range from 10−9 Pa to 10−5 Pa for N2, Ar and H2. ► The uncertainty of the generated pressure was estimated to be 4.8% (k = 2). ► The characteristics of ultrahigh vacuum gauges (stabilities of the pressure reading, the linearity of the sensitivity, the temperature dependence, and the long-term stability) were examined.