Correction circuit for a static magnetic field of an NMR apparatus and NMR apparatus for utilizing the same

摘要

In the NMR apparatus (200) the resonant conditions may be kept constant by adjusting the strength of the static magnetic field (Ho). The echo signal that is induced under the specific conditions (Ho, Gz, 90° and 180° RF pulses) is processed so as to obtain the deviation of the resonant frequency (Δω) in the correction circuit (100). The shift of the given static magnetic field (AH) is calculated based upon the deviation of the resonant frequency (Δω). The DC energizing current for the Ho power supply (13) is varied based upon the magnetic field shift (AH) so as to maintain the NMR phenomenon at the desirable resonant conditions.