Portable NMR sensor

Since it was proposed in the early 1980s [6, 7], spin-relaxation has been extensively used to determine the surface-to-volume ratio of porous materials [8-10]. Pore structure has been probed by the effect on the diffusion coefficient [11, 12] and the diffusion propagator [13,14], Self-diffusion coefficient measurements as a function of diffusion time provide surface-to-volume ratio information for the early times, and tortuosity for the long times. Recent techniques of two-dimensional NMR of relaxation and diffusion [15-21] have proven particularly interesting for several applications. The development of portable NMR sensors (e.g., NMR logging devices [22] and NMR-MOUSE [23]) and novel concepts for ex situ NMR [24, 25] demonstrate the potential to extend the NMR technology to a broad application of field material testing. 

Relaxation can be probed in inhomogeneous fields, so that the homogeneous polarization field B0 is not a necessity for successful applications of soft-matter imaging. Based on this fact, small portable NMR sensors can be built, which provide NMR data from a single volume element with the same specificity as the contrast in an NMR image [12]. Such... 

The NMR-MOUSE is a portable NMR sensor which works in highly inhomogeneous magnetic fields. Because of field inhomogeneity NMR spectroscopy of the chemical shift is not readily possible, but relaxation times and parameters of translational motion can be measured by echo techniques. These are the most important NMR parameters which are exploited for contrast in imaging. Unless fluids are investigated field inhomogeneities are essentially no obstacle for relaxation analysis [80], because molecular motion by translational diffusion is absent. 

R148 R. Gianferri and E. Brosio, Prospects for Nuclear Magnetic Resonance Future A Brief Note on Portable NMR Sensors , in Basic NMR in Foods Characterization, ed. E. Brosio, Research Signpost, Trivandrum, India, 2009, p. 137. 

Perlo, J., Demas, V., Casanova, F. et al. (2005) High-resolution NMR spectroscopy with a portable single-sided sensor. Science, 308 (5726), 1279. 

Volume-selective MRI using an adjustable, single-sided, portable sensor This sensor can probe the interior of samples nondestructively by collecting images and measuring relaxation and dilfusion constants, and even perform chemical analysis under conditions inaccessible to conventional NMR. MRI in axial and sagittal planes at dilferent depths of the sensitive volume and T-1-weighted contrast in a tissue sample are introduced. 

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