Fig. 3. Dependence of the longitudinal relaxation time, T₁, as determined by stray field (STRAFI) nuclear magnetic resonance (NMR) on the nominal pore diameter for a series of water-saturated ceramic discs in a single phantom, each with a narrow pore-size distribution and high porosity (ca. 35%). The T₁ recovery curve was fitted with a single exponential. The line is a weighted least squares fit to the data.