Mixture gas permeation model for stored VED

A permeation theoretical model is proposed based on competitive adsorption for estimating the permeation effect on the stored vacuum electronic devices (VED) surrounded by mixture gases, in which the parameters are determined by experimental results. The life expectation that the pressure inside a stored VED rises to the critical value, induced by permeation, is also set up based on the model. As an example, a VED stored over 20 years in surrounding of mixture gases is used to validate the model. The life expectation for the VED simulated by the model is about 42 years which is more consistent with the actual result than that by two conventional formulas. Obviously, the model proposed is suitable to estimate the permeation effect on the stored VED.