Nuclear magnetic resonance (NMR) relaxometry and diffusometry have many applications, and can be used when high resolution NMR spectroscopy is either impractical or not required, such as in medical imaging or oil-well logging. These techniques are usually used in ex situ measurements, that is, the detector is surrounded by the sample or probes its surface. However, it is difficult to generate a homogeneous magnetic field over a large sample area.
Paul J. Ganssle, Alexander Pines, and their co-workers at the University of California, Berkeley, USA, the Lawrence Berkeley National Laboratory, and the National Institute of Standards and Technology (NIST), have shown that a high-sensitivity optical magnetometer can be used to resolve a mixture of hydrocarbon solvents and water. They used an alkali-vapor-cell magnetometer to carry out one- and two-dimensional relaxation and diffusion experiments, and showed that useful NMR measurements could be taken at low field. The technique has some limitations, but represents a step towards to portable non-cryogenic NMR sensors.
- Ultra-Low-Field NMR Relaxation and Diffusion Measurements Using an Optical Magnetometer
Paul J. Ganssle, Hyun D. Shin, Scott J. Seltzer, Vikram S. Bajaj, Micah P. Ledbetter, Dmitry Budker, Svenja Knappe, John Kitching, Alexander Pines
Angew. Chem. Int. Ed. 2014.