基于静态膨胀法的极小漏率校准方法研究

Calibration of Extremely Low Leak Rate by Static Expansion

提出了一种基于静态膨胀法的极小漏率校准方法。该方法通过测量被校漏率离子流上升率及四极质谱计校准系数实现校准。实验发现,10-10Pa·m3/s量级极小漏率的离子流上升率重复性良好;采用混合气体二级膨胀能有效降低复杂膨胀过程对四极质谱计校准系数重复性引入的测量不确定度。通过对一支10-10Pa·m3/s真空漏孔的校准实验,证明基于静态膨胀法的极小漏率校准方法有效可行。当进一步减小校准室容积时,该方法能够实现10-13Pa·m3/s量级极小漏率的校准。

A novel technique was developed to calibrate extremely low leak rate by static expansion. In the newlydeveloped calibration technique, the rising rate of He-ion current and calibration coefficient of quadrupole mass spectrometer were evaluated. Good repeatability was obtained in measuring the rising rate of He ion current, originated from an extremely low leak rate of the magnitude of 10^-10 Pa· m^3/s. Furthemlore, a two-stage static expansion of a gas-mixture not only provides better calibration coefficient of the quadrupole mass spectrometer, but also bypasses the complicated expansion involved. The new technique was tested by calibrating a leak rate of 10^- 10 Pa· m^3/s with satisfactory results. We suggest that with decreased volume of calibration chamber, the new technique may reduce the lower calibration limit down to 10^- 13 Pa· m^3/s.