Patent ID: 7567156

Claim:
A superconducting magnet configuration, the configuration comprising: a cryostat at a cryogenic temperature; a magnet coil of inductance L larger than 10 H [Henry], said magnet coil disposed in said cryostat and generating a temporally stable magnetic field in a working volume which is suitable for NMR measurements; an external current source supplying a current strength I PS ; current feed lines connected between said current source and said magnet coil for passing said current strength I PS from said current source to said magnet coil; and a switch, said switch structured, disposed and dimensioned to exclusively short-circuit said magnet coil at said cryogenic temperature, wherein said switch is normally conducting and comprises a mechanically operable bridge having a definable ohmic resistance R 1 smaller than 10 −3 Ω, said switch and parts of said bridge being disposed within said cryostat, wherein said external current source has a ripple whose frequency dependence is such that a relative stability of the magnetic field generated by said magnet coil exceeds a relative stability of said external current source, associated with said ripple, by at least three orders of magnitude.