Selective enhancement of H signal from water and oil in porous media at low field with Overhauser DNP.

In porous media MR studies, discriminating between oil and water presents a challenge because MR lifetimes are often similar and spectra overlap. Low saturations might suggest an experimental strategy of increasing the static field for increased sensitivity, but susceptibility effects are exacerbated at higher field. Overhauser dynamic nuclear polarization, effective at low static field, was employed with water and oil-soluble nitroxide to selectively enhance water and oil signals.

A low-field ceramic magnet design for magnetic resonance.

We describe the design of a low-field portable magnet, based on two ceramic magnets, separated by a distance, with their magnetic poles aligned to create a large homogeneous region with a field strength of 425 gauss. Ceramic magnets are an uncommon choice compared to Neodymium Iron Boron magnets for low-field magnetic resonance but are preferable for our purposes to create a homogeneous region at lower field strength. The low cost of large ceramic magnets results in an inexpensive design with a large measurement volume.

Design and validation of a single-sided magnet with a constant gradient parallel to its surface.

We present the design, validation, and testing of an optimized 5 MHz three-magnet array with a gradient parallel to the magnet surface. An approach to permanent magnet array design is explored with a genetic algorithm. The genetic algorithm was used to produce multiple designs based on an inventory of available block magnets.