A shielded superconducting MRI magnet system uses a multi-layer shielded
coil design. By splitting the magnet coils into a plurality of coil
layers, an increased number of degrees of freedom is achieved which, in
turn, permits minimization of the overall length of the magnet while
nevertheless avoiding excessive magnet field and stress values in the
coils. A compact coil system is thereby designed which also satisfies the
plurality of MRI requirements with regard to sufficiently large
investigational volume, magnet field strength, acceptable homogeneity,
and magnet stray field limitation while achieving sufficiently low
maximum coil B field strengths and stress values to avoid quenches and
maintain the structural integrity of the magnet.