The University of New Brunswick

Andrew E Marble

Bruce J Balcom

Bruce Colpitts

Igor V Mastikhin

Joshua J Young

A magnet array is disclosed which is suitable for inter alia producing a remote field for use in unilateral magnetic resonance. In the 'Magnet Array', two separated magnets, which are magnetized along a substantially same collinear magnetization direction, produce a field with a local maximum centered above and between them. The field produced by the two separated magnets is substantially parallel to the collinear magnetization direction of the two separated magnets. A third magnet is centered between the two separated magnets. The third magnet has a magnetization direction which is substantially parallel to the collinear magnetization direction of the two separated magnets. The third magnet produces a field which is substantially parallel to the collinear magnetization direction of the two separated magnets, and adds to the increasing field below the local maximum point produced by the two separated magnets. The field of the third magnet, which decays with distance, adds to the increasing field below the local maximum point. The position of the third magnet is selected in order to generate a total field which has at least one of its first and second spatial derivatives with respect to the distance above the magnet array substantially equal to zero.

Magnet array

A unilateral NMR sensor comprising a ferromagnetic yoke; a permanent magnet arranged on the yoke; a pole piece on the magnet; the pole piece including an air-pole piece interface surface whose shape corresponds to an equipotential contour of magnetic scalar potential. An approach for designing single-sided magnets suitable for unilateral magnetic resonance (UMR) measurements is presented. The method uses metal pole pieces to shape the field from permanent magnets in a target region. The pole pieces are shaped according to solutions to Laplace's equation, and can be designed using a combination of analytical methods and numerical optimization. The design leads to analytical expressions for the pole piece shape and magnetic field. The method is developed in Cartesian, polar, and spherical coordinates, and the merits of each system are discussed. The effects of finite magnet size on the field quality are explored through simulation, and are found to have a substantial effect in many cases. A magnet is designed using our method to produce a static field with a constant gradient over a region 2 cm in diameter and 2 mm thick. This leads to a compact cylindrical magnet just over 11 cm in diameter, topped with a single metal pole piece. The design is validated through simulation. The simulated field is found to agree closely with that specified analytically through the design procedure.

Magnetic field generator suitable for unilateral nuclear magnetic resonance and method for making same

A probe suitable for use in unilateral nuclear magnetic resonance imaging and adapted to be embedded in a sample to be analysed, the probe comprising; a static magnetic field generator; a radiofrequency magnetic field generator adjacent to the static magnetic field generator; a circuit controlling the frequency response of the radiofrequency magnetic field generator, adjacent to the static magnetic field generator; an input cable coupled to the frequency control circuit and the frequency control circuit coupled to the radiofrequency magnetic field generator.

Probe, system and method suitable for unilateral nuclear magnetic resonance

A unilateral NMR sensor comprising a ferromagnetic yoke; a permanent magnet arranged on the yoke; a pole piece on the magnet; the pole piece including an air-pole piece interface surface whose shape corresponds to an equipotential contour of magnetic scalar potential.

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Maberly, Canada

Andrew E Marble