Estimation of the Characteristic Length Scales forB0Variation Using the OE-CTPG Pulse Sequence

NMR measurement of diffusion is a well-established tool for investigating the microstructure of heterogeneous materials. Since an applied magnetic-field gradient is an essential element of the pulse sequences usually used, any magnetic-field gradients present within the sample may interfere with the NMR measurement, in some cases making it impracticable. Here, a method that uses the internal gradients themselves to provide information about the heterogeneous structure, in materials where these gradients are strong, is described. The technique is demonstrated using a range of solvents in packs of different sizes of glass beads.