Patent ID: 7282918

Claim:
A nuclear magnetic resonance apparatus for generating a homogeneous static magnetic field in a z-direction, the apparatus comprising: at least one coil/resonator system for transmitting and/or receiving radio frequency (RF) signals at at least one measuring frequency; a gradient system for generating pulsed field gradients in at least one spatial direction; and a shielding configuration disposed radially between said at least one coil/resonator system and said gradient system, said shielding configuration having at least one electrically conducting layer with at least one slot, said electrically conducting layer being disposed about a center of said shielding configuration to be axially symmetrical with respect to a z-axis, wherein, in an axial section z 1 <z<z 2 with z 2 −z 1 >L, with L being equal to a window length of said coil/resonator system containing at least 90% of the magnetic field energy of said coil/resonator system, said shielding configuration defines at least one pair of regions disposed about the z-axis, said regions having a cylinder envelope shape, with two regions of each pair being defined by two respectively closed limiting lines circulating about the z-axis, wherein two limiting lines of each said region have a mutual axial separation from each other of a ≤ z ⁢ ⁢ 2 - z ⁢ ⁢ 1 2 and are disposed at planes parallel to a xy plane, wherein two regions of said pair are geometrically positioned to oppositely inductively couple to said at least one coil/resonator system for at least some eigenmodes of said shielding configuration.