Abstract
Development of the precision gas generator tagged by a very small amount of the released gas rate in weight change (g/sec) has been strongly desired for exactly calibrating vacuum instruments.
The gas-liquid equilibrium type, permeation tube (P-tube) for the Japanese Industrial Standards (JIS) to prepare the released rate of a calibration gas in an atmospheric pressure has not been used in vacuum elsewhere. Therefore in this study, the performance of the P-tube in vacuum environment was evaluated. A weight change of the P-tube was measured with our original vacuum microbalance, and concentrations of the released gas components were concurrently measured with the Electron Ionization Quadrupole Mass Spectrometer (EI-QMS), both in the different P-tube temperatures. The resultant correlation between the vacuum microbalance and the EI-QMS was discussed.
The weight change rate of the sample propane (C3H8) and butane (C4H10) gases encapsulated in the P-tube were nearly identical from 35°C to 45°Cand from 40°C to 50°C, respectively. The EI-QMS peak intensities of m/z=29 (propane) and m/z=43 (butane) indicated constant values, both in the above temperature ranges.
These results can be positioned to the initial performance data for realizing the weight change rate tagged precision gas generator in vacuum by using the P-tube.
