Polyhedral coil systems having a large homogeneity volume and large access zone

A coil system (30, 40, 50) for generating a homogeneous magnetic field, the coil system (30, 40, 50) comprising a coil assembly (2), each coil assembly (2) being composed of at least two coils (S1, S2, S3), the respective windings (W1, W2, W3) of said coils (S1, S2, S3) forming plane-parallel, rotationally symmetrical surfaces having different sizes and a common axis of rotation as a coil axis (4) running perpendicular to the surfaces, a current flowing in the opposite direction in relation to another one of said coils through at least one of said coils (S1, S2, S3), further comprising

• at least three coil assemblies (2), the coils (S1, S2, S3) of each coil assembly (2) being located inside and oriented plane-parallel to the base surface of a generating pyramid, the apex of which coincides with the center of a regular, convex polyhedron and the base surface of which is identical to a surface of the convex polyhedron in which the projection of the pyramid apex onto the pyramid base surface coincides with the center of the pyramid base surface, wherein the polyhedron is a tetrahedron, a hexahedron, an octahedron, a dodecahedron or an icosahedron which has n surfaces can be composed of n generating pyramids in a volume-filling manner.