固定流导法真空漏孔校准装置

Calibration of Ultra-Low Leak Rate with Constant Conductance Technique

为了精确校准较小漏率真空漏孔,研制了固定流导法真空漏孔校准装置。在漏孔校准过程中,通过调节稳压室中的压力,很容易使标准气体流量与漏孔漏率非常接近或相等,从而避免四极质谱计的非线性影响。通过实验测试,校准装置的极限真空度为3.7×10-6Pa,漏率校准范围为10-5Pa.m3/s^10-11Pa.m3/s,合成标准不确定度为1.4%~4.2%。

A novel type of apparatus has been developed to accurately calibrate the ultra-low leak rate with constant conductance method. In calibrating the leak, the pressure in the ballast chamber can be precisely controlled in such a way that the standard gas flow through the orifice is close or equal to the leak rate. As a result, non-linearity of the quadrupole mass spectroscopy is not a problem. In our experiments, the leak rate calibration ranges from 10^-5 Pa·m^3/s to 10^-11 Pa·m^3/s and the combined standard uncertainties are in the range of 1.4% to 4.2% at the highest base vacuum of 3.7 × 10^-6 Pa.