Abstract:
This paper tested part performance of the latest developed portable calibration apparatus of mass spectrometers for partial pressure. The ultimate vacuum of the device was measured using a reference ionization gauge; The diameter and the thickness of the gas-operated element which conductance is about 10
−2 m
3/s could be measured accurately and the conductance was calculated using formular under the molecular flow condition. The conductance of the gas-intaked conductance elements with micro-meter apertures was measured using constant volume experiments. The back-streaming ratio is obtained using the same vacuum gauge to measure the gas pressure at both sides of the gas-operated conductance elements. The experimental results proved that the ultimate vacuum of the device is 4.8×10
−7 Pa. The conductance of the gas-exhausted element for N
2 is 1.37×10
−2 m
3/s. The conductance of two gas-intaked conductance elements for N
2 are 3.81×10
−6 m
3/s and 4.50×10
−8 m
3/s respectively. The back-streaming ratio for N
2 is 0.193 .Based on analysis, the calibration range of the device for N
2 is (4×10
−2~5×10
−6)Pa.