MAGNETIC SHIMMING AND MAGNET ARRANGEMENTS

摘要

A passive magnetic field shim arrangement including a plurality of shim pairs. For shimming a number of magnetic field harmonics, each shim pair may include a first shim and a second opposite and substantially equal shim, each shim pair being configured for shimming one of the magnetic field harmonics. Each shim pair may include a first shim of order N and a second opposite and substantially equal shim of order N, the first and second shims together defining a magnetic field shim correction of order N−1. Each shim may include one or more shim elements arranged on a non-magnetic tubular support, the tubular supports being dimensioned such that the tubular supports may be arranged concentrically in relation to each other. A magnetic field may be shimmed by providing a shim pair configured for shimming a magnetic field harmonic, the shim pair including a first shim and a second opposite and substantially equal shim and symmetrically adjusting an axial position of the first shim and an axial position of the second shim to provide a desired shimming magnitude in order to shim the magnetic field harmonic.

主权项

1. A passive magnetic field shim arrangement including a plurality of shim pairs, each shim pair including a first shim of order N and a second opposite and substantially equal shim of order N, the first and second shims together defining a magnetic field shim correction of order N−1.