Patent ID: 6265960
Filing Date: 2001-07-24
Classification: G01R

Abstract:
A superconducting magnet system for a magnetic resonance spectrometer, the magnet system having an actively shielded superconducting magnet for generating a homogeneous magnetic field along a z-axis in a working volume disposed about z=0, the superconducting magnet system also having a superconducting shim coil system for correcting magnetic field inhomogeneities in the working volume, the superconducting magnet system comprising:a radially inner coil system;a radially outer coil system, said radially inner and said radially outer coil systems carrying approximately equal currents and having approximately equal and opposite dipole moments;a radially inner shim coil set, said inner shim set substantially inductively decoupled from both said radially inner coil system and said radially outer coil system, said inner shim set substantially generating a magnetic field in the working volume whose z component varies like .DELTA.H.sub.0 +C.sub.2 z.sup.2 with C.sub.2 =constant; anda radially outer shim coil set, said outer shim set substantially inductively decoupled from both said radially inner and said radially outer coil systems, said outer shim set substantially generating a magnetic field of -.DELTA.H.sub.0 in the working volume.