The performances of the monopole mass spectrometer were analyzed that it had high resolving power and focusing property. The monopole mass spectrometer whose electrode length was 100mm and r0=5mm had been designed and manufactured. The resolving power and mass range of it had been measured. The researching results indicated: The mass range of the device was 223. The resolving power achieved 30 measured at 10% peak height of the N2^+. The device could he used in residual gas analysis.
The mass spectrometer and the method of measuring concentration of oxygen in the region of mouth and nose in vivo experiment under low pressure were developed. A mass flow controller was assembled through the inlet capillary of MGA-1100 mass spectrometer. The mass flow controller was controlled by a computer controlled the operating pressure in MGA -1100 to make operating in its linear region. The measuring value is not affected from the pressure of inlet. MGA-1100 mass spectrometer with improved inlet system can reach the demand of most human experiment under low pressure.
