Abstract: In an apparatus having at least one detection coil (1) for the detection of nuclear magnetic resonance (NMR) from a sensitivity region of the detection coil (1) in the ground, whereby nuclear spins within the sensitivity region are excited by repeated coherent excitation, in each case, to precess in the earth's field and produce a small NMR induction voltage in the detection coil (1) which is introduced to a first amplifier (7), the detection coil (1) consists of at least two oppositely wound partial coils (2, 3) having parallel coil axes which are connected electrically in series and at least one compensation coil (8, 9, 10) is provided for additional compensation of spatially inhomogeneous interfering fields whose induction signal is introduced to a second amplifier (18, 19, 20) having adjustable amplification. In this fashion, in addition to the homogeneous portion, an inhomogeneous portion due to distant disturbances can be eliminated from the measured signal.

Abstract: The invention is a method and apparatus for performing high speed, high resolution nuclear magnetic resonance imaging wherein the magnetic coils for inducing the desired magnetic fields and receiving the magnetic field caused by NMR are positioned to one side of the volume under observation. Disclosed coil configurations provide a relatively large volume homogenous Ho field and three orthogonal gradient fields, so as to create a relatively large volume of observation which is broken up into high resolution voxels by appropriate selection of each of the gradient fields. The voxel is shifted in space at time intervals by scaling one or more of the gradient fields at such time intervals.