PLANAR MAGNET ARRANGEMENT FOR NUCLEAR MAGNETIC RESONANCE

摘要

An NMR apparatus (300) has a magnet arrangement (301) comprising three permanent magnets (302, 303, 304). The magnets (302, 303, 304) are arranged along a line with the central magnet (303) having its S pole facing upwards and the two other magnets (302, 304) having their N poles facing upwards to generate a magnetic field B<SUB>o</SUB>. Two probe coils (306, 307) are positioned over the magnets (302, 303, 304). The centre of each of the coils (306, 307) is between a respective adjacent pair of the magnets (302, 303, 304), substantially equidistant from the centre of the pole at the top of each magnet (302, 303, 304) of the pair. The probe coils (306, 307) are connected to an electrical power source (not shown) in opposing directions such that when a current is passed though them by the power source, they generate a magnetic field B, that has opposing directions at the centre of each coil (306, 307) creating effective N and S poles offset from the poles of the magnets (302, 303, 304) of the magnet arrangement (301). The magnets (302, 303, 304) of the magnet arrangement (301) and probe coils (306, 307) are arranged such that the magnetic fields B<SUB>o</SUB>, B<SUB>1</SUB>, they generate vary in strength only with height above the magnet arrangement (301) and vary in direction sinusoidally along the line of the magnet arrangement (301) orthogonal to one another in a sample volume, facilitating NMR measurement.