可逆吸着相にある真空系の排気特性のモデリング Modeling of the Pumping Down of a Vacuum System of a Reversibly-adsorbed Phase
In order to consider the outgassing behavior in the pump-down of a vacuum system of a reversibly adsorbed phase, modeling of the pump-down based on the Temkin isotherm was attempted. In the modeling, two variables of relative surface coverage θ and gas density <I>n</I> are used, and a set of the conservation of mass equations which predicts changing rates of θ and n with time during pumping down, were derived. By combining the two equations, solutions of θ (<I>t</I>) and <I>n (t) </I> were derived analytically as a function of time. Then, using the solution <I>n (t) </I>, the measured outgassing rate <I>q (t) </I> was expressed as a product of a pumping speed dependent term and a time dependent term. In addition, it was shown that the theoretical outgassing expression can consistently explain the experimental results for the dependence of the outgassing rate on pumping speed, which were observed in the pump down of a 304 stainless steel chamber and a TiN coated 304 stainless chamber after exposure to moist air.
真空 42(6), 620-627, 1999-06-20
The Vacuum Society of Japan