A Study of H1 NMR Signal from Hydrated Synthetic Sands

Abstract

Magnetic resonance imaging (MRI) has recently been proposed as an in situ subsurface imaging technique for locating buried objects in fully hydrated soils. This paper explores the available hydrogen [Formula: see text] nuclear magnetic resonance (NMR) signal from water in fully hydrated monodispersed synthetic sands (glass beads) as a predictor of the utility of subsurface MRI. The MRI signal from hydrated soils is a function of three main properties of water in the voids between the soil particles: the spin-lattice relaxation rate [Formula: see text], the spin-spin relaxation rate [Formula: see text], and the spin density [Formula: see text]. The [Formula: see text] values were measured for random close packed synthetic sands as a function of particle diameter. The [Formula: see text] and [Formula: see text], values were measured at a magnetic field strength of [Formula: see text] as a function of particle diameter. [Formula: see text] was also measured as a function of magnetic field strength at 0.235, 2.35, 23.5, and [Formula: see text]. The synthetic sands studied have a predictable [Formula: see text] and [Formula: see text], and a constant [Formula: see text]. The water in these sands also has a predictable [Formula: see text] as a function of applied magnetic field. Therefore, fully hydrated monodispersed real sands are expected to have a predictable NMR signal.