Actively shielded magnet system with Z2 shim
US6265960A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 23, 2000 |
| Grant date | Jul 24, 2001 |
| Priority date | — |
| Expiry date | Aug 23, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R33/3875
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A magnet system for magnetic resonance spectrometers comprising an actively shielded superconducting magnet with a radially inner and a radially outer coil system (M.sub.1, M.sub.2), wherein the two coil systems carry the same current and have identical opposite dipole moments, and comprising a shim coil system for correcting magnetic field inhomogeneities in the working volume, whose z component varies in proportion to z.sup.2, is characterized in that the shim coil system comprises a radially inner shim coil set (S.sub.i) which is inductively decoupled from the magnet system and generates a magnetic field in the working volume, whose z component varies like .DELTA.H.sub.0 +c.sub.2.multidot.z.sup.2 with c.sub.2 =const., and a radially outer shim coil set (S.sub.a) which is also inductively decoupled from the magnet system and generates a homogeneous magnetic field -.DELTA.H.sub.0 in the working volume. This produces a Z.sup.2 shim system with technically simple means which is, on the one hand, compact and does not waste any unnecessary space in the area of the magnet windings, and on the other hand is not susceptible to disturbances due to fluctuating external magnetic fields.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.