A constant gradient unilateral magnet for near-surface MRI profiling |
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Authors: | Marble Andrew E Mastikhin Igor V Colpitts Bruce G Balcom Bruce J |
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Institution: | MRI Centre, Department of Physics, PO Box 4400, University of New Brunswick, Fredericton, New Brunswick, Canada E3B 5A3. |
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Abstract: | The design and construction of a unilateral NMR (UMR) magnet assembly for near-surface 1D profiling is presented. The arrangement consists of a single permanent magnet topped with a shaped iron pole cap. The analytically determined profile of the pole cap shapes the field over the magnet, giving a constant gradient of 31 G/cm over a 8mm depth at a 1H frequency of 4.26 MHz in a spot approximately 5 mm wide. The moderate gradient allows 1D profiling of planar samples with a frequency encoded spin-echo experiment. The curvature of the magnetic field limits the available resolution to 100's of microm. The device is suitable for profiling planar samples in which a coarse resolution but large spatial extent is desired. |
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Keywords: | Unilateral magnetic resonance Inhomogeneous fields Magnet design Profiling |
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