Abstract

A nuclear spin resonance (NMR) measuring device, in particular an NMR tomography apparatus with a preferentially superconducting main field coil which is capable of producing, within a measurement volume whose center is coincident with the origin of a Cartesian coordinate system x, y, z, a homogeneous static magnetic field B0 in the direction of the z-axis of this coordinate system and with a tesseral gradient coil system for the production of magnetic gradient fields with a largely linear dependence within the measuring volume in a direction perpendicular to the z-axis, whereby the gradient coil system comprises at least four largely identical saddle-type partial coils arranged symmetrically with radial and axial separations from the coordinate origin, the partial coils each exhibiting two electrically conducting segments which run about the z-axis in the azimuthal direction one segment (21) of which has as small a radial separation r1 and the other segment (22) as large a radial separation r2 as possible from the z-axis, is characterised in that both azimuthal segments (21, 22) exhibit an axial separation from each other in the direction of the z-axis, whereby the radially outer segment (22) with the radial separation r2 from the z-axis is, with respect to the z-axis, arranged axially closer to the coordinate origin than the radially inner segment (21) with a radial separation r1 from the z-axis, and whereby both segments (21, 22) are connected to each other by means of conducting sections (23). With this configuration an unhindered sideward access to the investigational volume of the NMR measuring device is achieved with sufficient produced gradient field linearity in the measuring volume.