| 摘要 |
A magnet array for use with NMR signal acquisition apparatus uses rod-shaped magnets located at the corners of a square. The square lies in the (x-y) plane of a three dimensional Cartesian coordinate system and the long axes of the magnets extend generally along the z-direction such that the polarisation vectors of the magnets lie substantially in the x-y plane. The magnets are arranged to create a substantially uniform magnetic field B0 in a sample volume at the centre of the polygon. The widths of the magnets are less than the length of the sides of the square so that there is a gap between magnets allowing lateral access in the x-y plane to the sample volume. Each magnet may be rotatable about its longitudinal axis to change one and/or both the B0 field direction and magnitude in the sample volume. At least one magnet may be displaceable in a direction orthogonal to its longitudinal axis to change one and/or both the B0 field direction and magnitude in the sample volume.
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