| 摘要 |
A magnet system for magnetic resonance spectrometers comprising an actively shielded superconducting magnet with a radially inner and a radially outer coil system (M1, M2), wherein the two coil systems carry the same current and have identical opposite dipole moments, and comprising a shim coil system for correcting magnetic field inhomogeneities in the working volume, whose z component varies in proportion to z2, is characterized in that the shim coil system comprises a radially inner shim coil set (Si) which is inductively decoupled from the magnet system and generates a magnetic field in the working volume, whose z component varies like DELTAH0 +c2.z2 with c2=const., and a radially outer shim coil set (Sa) which is also inductively decoupled from the magnet system and generates a homogeneous magnetic field -DELTAH0 in the working volume. This produces a Z2 shim system with technically simple means which is, on the one hand, compact and does not waste any unnecessary space in the area of the magnet windings, and on the other hand is not susceptible to disturbances due to fluctuating external magnetic fields.
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