METHOD FOR MEASURING RATE OF PERMEATION OF VAPOR THROUGH SAMPLE

摘要

A method for measuring the rate of permeation of a vapor through a sample. A sample (14) covers an opening (13) of a gas chamber (12) and thereby seals a gas cell (10) which forms the gas chamber. A water drop (16) containing an isotope having a mass number of 20 is placed in the gas chamber (12), and the gas cell (10) is arranged in the vicinity of a mass spectrometer (7) in a vacuum chamber (1). The partial pressure of a vapor in the vacuum chamber (1) is measured by the use of the mass spectrometer (7) after the elapse of a time sufficient for the saturation of the gas chamber (12) with the vapor and for the stabilization of the output of the mass spectrometer (7). A rate of permeation of the vapor through the sample (14) is determined by using the partial pressure measured.