AVS 59th Annual International Symposium and Exhibition
    Vacuum Technology Monday Sessions
       Session VT-MoA

Paper VT-MoA6
Measurement of Gas Transport in Solids by a Saturation/Outgassing Method

Monday, October 29, 2012, 3:40 pm, Room 14

Session: Gas Flow, Leaks, Permeation and Mass Analysis
Presenter: L. Wang, Los Alamos National Laboratory
Authors: L. Wang, Los Alamos National Laboratory
J.A. Tanski, Los Alamos National Laboratory
R.Y. Weinberg, Los Alamos National Laboratory
Correspondent: Click to Email
Common flow techniques for measuring gas transport properties in solids requires the formation of a membrane which serves as a barrier to the movement of gas and the formation of leak-tight seal so the gas is diffusing through the membrane. However, for many materials, especially brittle non-metallic ionic solids, meeting these two requirements are difficult. In this study, an alternative method based on first saturating the material with the gas at a known pressure and subsequently allowing the absorbed gas to diffuse out to a static vacuum environment was developed for measuring gas transport properties of this type of materials. The method uses a sample of a well-defined geometry, in this case a right cylinder, and a computer program (DiSol) was developed to model the desorption process and extract diffusivity and solubility from the measured outgassing curve. To demonstrate the viability of the method, helium transport in a high-density polyethylene (HDPE) cylinder was measured, and the results obtained compared well with the published diffusivity and solubility values. The details of the method and the HDPE data obtained in this study will be presented.