Calibration Apparatus of Vacuum Leak by using Constant Conductance Method

摘要

A calibration apparatus of vacuum leak by using constant conductance method was developed to accurately calibrate vacuum leak with small leak rate. In calibration of vacuum leak, the gas pressure in the ballast chamber is adjusted precisely to make standard gas flow through the orifice very near or equal to the leak rate of calibrated vacuum leak so that the influence by non-linearity of quadrupole mass spectrometer can be avoided. By experimental measurements, the calibration range of leak rates is from 10~(-5) to 10~(-10) Pa(centre dot)m~(3)/s, and the combined standard uncertainties are from 1.4percent to 4.2percent.