Apparatus for mapping static magnetic fields

摘要

Apparatus for mapping a static magnetic field is provided. An NMR-suitable sample or array of samples is positioned in a magnetic field probe adapted to generate an alternating magnetic field and for measuring an induced signal from the sample as a result of being exposed to the alternating magnetic field. The induced signal from the sample is measured at discrete points along a helispherical or heliellipsoidal path located within the static magnetic field. Shim coils can be positioned within the static magnetic field and the current directed to the coils can be controlled as a result of the field mapping results in order to homogenize the static magnetic field. Ferromagnetic elements can be inserted in appropriate locations instead of, or in addition to, the shim coils. One such probe or any array of such probes are mounted on an actuator mechanism, which mechanism moves the probe or array of probes along a helispherical or heliellipsoidal path located within the static magnetic field. Induced signals are acquired from each probe at each of the positions along the path of the mechanism.