Assembly for generating magnetic fields in a magnetic resonance tomography apparatus that allows use of a superconducting gradient field device

A magnetic resonance imaging system comprising:

• a magnetic resonance data acquisition device configured to interact with an examination subject, said magnetic resonance data acquisition device having an assembly comprising a superconducting magnet device that generates a basic magnetic field, said superconducting magnetic device comprising a superconducting coil having a plurality of windings, a vacuum vessel that surrounds said superconducting magnet device, said vacuum vessel having a non-conductive wall, a superconducting gradient field device, if not in a magnetic field above an impairing magnetic field strength, operable to generate a rapidly switched gradient field, and said non-conductive wall of said vacuum vessel forming, in combination with said superconducting coil, a region between windings of said superconducting coil in which said superconducting gradient field device is disposed, and a magnetic field source that produces a reduced magnetic field in said region having a magnetic field strength below said impairing field strength to allow said operation of said superconducting gradient field device to generate said rapidly switched gradient fields;
• and
• a control unit that operates said superconducting gradient field device to generate said rapidly switched gradient field.