Sensitivity analysis of an improved method for measuring the radon diffusion coefficient of porous materials

Publisher Summary Diffusion of radon in building materials is a major driving force for radon exhalation into buildings with relatively low radon concentrations. The common approach to measure this material parameter in the laboratory is to position a porous sample between two compartments. In one of the chambers a known high radon activity concentration is introduced while the radon concentration in, or flux into, the other (ventilated) chamber is measured. Several techniques are available for determining the radon diffusion coefficient of porous materials. The common approach is to position a porous sample between two compartments. In one of the chambers a known high radon activity concentration is introduced while the radon concentration in the other chamber is measured. A steady state or transient analysis may be utilized. In this chapter, a transient analysis is outlined for two experimental conditions in a cylindrical geometry, complemented with a rigorous treatment of the counting uncertainty in a continuous radon measurement. The sensitivity and accuracy of a least-squares regression to calculate the diffusion coefficient from artificially generated data is discussed.