Abstract: A magnetic measurement apparatus includes a magnet system (1) for generating a steady magnetic field in a measurement space (35), a gradient coil system (3) for generating gradient fields in the measurement space, and a number of gradient amplifiers (9) with input terminals (38) which are connected to means (7) for generating an input signal exhibiting a predetermined variation as a function of time. The output terminals (39) of at least one of the gradient amplifiers (9) are connected to an output circuit which comprises a series connection of a gradient coil (3) and at least one capacitor (55). The output circuit also includes a transformer (41) with a primary winding (43) and a secondary winding (45), the primary winding being connected to the output terminals (39) of the gradient amplifier (9), the secondary winding constituting a series resonant circuit in conjunction with the gradient coil (3) and the capacitor.

Abstract: In a magnetic resonance apparatus a system of concentric cylinders of superconductive material maintain an effective steady magnetic field in a measured space within the inner cylinder which field is very homogeneous and is, moreover, very constant in time without requiring a large electric power. In a particular embodiment a magnetic field cylinder produces a strong magnetic field, a stabilization cylinder within the magnetic field cylinder ensures a good homogeneity and stabilization of the effective magnetic field, while a screening cylinder provided outside the magnetic field cylinder reduces the external stray field of the system.