A portable nuclear magnetic resonance (NMR) surface probe was used to determine the time-dependent self-diffusion coefficient D(t) of water molecules in two fluid-filled porous media. The measuring equipment and the inhomogeneous magnetic fields in the sensitive volume of the probe are described. It is discussed how to evaluate D(t) using a surface probe from the primary and stimulated echoes generated in three-pulse experiments. Furthermore, the evaluation of D(t) allows one to determine the geometrical structure of porous materials.
Marko, Andriy, et al. “Application of a Portable Nuclear Magnetic Resonance Surface Probe to Porous Media.” Journal of Magnetic Resonance, vol. 185, no. 1, 2007, pp. 19–27., doi:10.1016/j.jmr.2006.10.009.