Microsc. Microanal. Microstruct. 6, 187-203 (1995)
DOI: 10.1051/mmm:1995118

Measurement of Diffusion in Liquids within Porous Solids by X-Ray Microradiography: Determination of Errors and Optimization of Experimental Conditions

Stephanie E. P. Dowker¹, Paul Anderson² et James C. Elliott<sup>2

1</sup>  Department of Conservative Dentistry
²  Department of Child Dental Health, The London Hospital Medical College, Turner Street, London E1 2AD, UK

Abstract
In principle, X-ray absorption measurements provide a straightforward method for determining local concentrations and fluxes, and hence local diffusion coefficeients, during diffusion of species with high atomic number, within liquids, gels or opaque porous solids. However the application of this method is limited by the errors arising from X-ray photon statistics, which cannot be calculated exactly by analytical methods. Numerical simulation has been used to investigate the influence of experimental variables on the errors in diffusion coefficients determined by an application of Fick's first law. From these, guidelines have been developed for optimization of experimental conditions.

PACS
6610C - Diffusion and thermal diffusion in liquids.
7870D - X ray absorption and absorption edges condensed matter.

Key words
diffusion -- X ray absorption -- X ray diffraction -- diffusion in liquids -- porous solids -- X ray microradiography -- error determination -- X ray absorption -- local concentrations -- fluxes -- local diffusion coefficients -- X ray photon statistics -- Fick's 1st Law


© EDP Sciences 1995