According to some aspects, a method of producing a permanent magnet shim configured to improve a profile of a B.sub.0 magnetic field produced by a B.sub.0 magnet is provided. The method comprises determining deviation of the B.sub.0 magnetic field from a desired B.sub.0 magnetic field, determining a magnetic pattern that, when applied to magnetic material, produces a corrective magnetic field that corrects for at least some of the determined deviation, and applying the magnetic pattern to the magnetic material to produce the permanent magnet shim. According to some aspects, a permanent magnet shim for improving a profile of a B.sub.0 magnetic field produced by a B.sub.0 magnet is provided. The permanent magnet shim comprises magnetic material having a predetermined magnetic pattern applied thereto that produces a corrective magnetic field to improve the profile of the B.sub.0 magnetic field.

A cylindrical superconducting coil assembly comprising a plurality of individual coil units stacked together and retained in place by retaining structures, each coil unit comprising a resin-impregnated annular superconducting coil bonded at its axial extremities to respective rings of non-ferromagnetic material.

A magnetic resonance apparatus may include at least one sensor and a controller. The magnetic resonance apparatus is positionable in an examination room. A spatial location of the magnetic resonance apparatus in the examination room can be determined using the sensor. In a method for supporting an adjustment of a shim parameter of a magnetic resonance apparatus, a current spatial location of the magnetic resonance apparatus in an examination room is determined using the sensor, and a shim parameter of at least one shim element of the magnetic resonance apparatus is determined based on the current spatial location of the magnetic resonance apparatus and information of a magnetic field database. The magnetic field database may include information about a spatial location of the magnetic resonance apparatus and also magnetic field data correlated with the spatial location.

A magnetic resonance apparatus may include at least one sensor and a controller. The magnetic resonance apparatus is positionable in an examination room. A spatial location of the magnetic resonance apparatus in the examination room can be determined using the sensor. In a method for supporting an adjustment of a shim parameter of a magnetic resonance apparatus, a current spatial location of the magnetic resonance apparatus in an examination room is determined using the sensor, and a shim parameter of at least one shim element of the magnetic resonance apparatus is determined based on the current spatial location of the magnetic resonance apparatus and information of a magnetic field database. The magnetic field database may include information about a spatial location of the magnetic resonance apparatus and also magnetic field data correlated with the spatial location.

An MRI scanner can include a magnet assembly forming a central magnetic field area, and a slot for receiving a shim drawer formed within the central magnetic field area. There can be included a shim drawer received within the slot. The shim drawer can be configured to carry one or more metal shim and the shim drawer can be formed of conductive material.

An arrangement for setting the spatial profile of a magnetic field in a working volume of a main field magnet (2), in particular a superconducting main field magnet, of a magnetic resonance installation. The main field magnet is arranged in a cryostat (1) and the spatial profile is set by a passive shim apparatus (3) with magnetic field forming elements which are arranged within the cryostat during operation and which have cryogenic temperatures. The magnetic resonance installation contains a room temperature tube (4), in which the sample volume is situated during operation. The passive shim apparatus is introduced into or removed from the cold region of the cryostat via a vacuum lock (5), without needing to ventilate the cold region of the cryostat. This provides a relatively simple, cost effective, and time-efficient method to carry out a stable field homogenization using a passive shim apparatus.

An arrangement for setting the spatial profile of a magnetic field in a working volume of a main field magnet (2), in particular a superconducting main field magnet, of a magnetic resonance installation. The main field magnet is arranged in a cryostat (1) and the spatial profile is set by a passive shim apparatus (3) with magnetic field forming elements which are arranged within the cryostat during operation and which have cryogenic temperatures. The magnetic resonance installation contains a room temperature tube (4), in which the sample volume is situated during operation. The passive shim apparatus is introduced into or removed from the cold region of the cryostat via a vacuum lock (5), without needing to ventilate the cold region of the cryostat. This provides a relatively simple, cost effective, and time-efficient method to carry out a stable field homogenization using a passive shim apparatus.

The present invention relates to a method of correcting inhomogeneity of the static magnetic field generated by the magnet of a Nuclear Magnetic Resonance imaging machine, wherein the magnet is flat and the magnetic field on one side of said magnet is corrected such that a volume is defined, which is bounded by a spherical cap surface, in which volume and along which surface the magnetic field is homogeneous, i.e. has field lines having equal parallel directions and equal intensities.

The present invention relates to a method of correcting inhomogeneity of the static magnetic field generated by the magnet of a Nuclear Magnetic Resonance imaging machine, wherein the magnet is flat and the magnetic field on one side of said magnet is corrected such that a volume is defined, which is bounded by a spherical cap surface, in which volume and along which surface the magnetic field is homogeneous, i.e. has field lines having equal parallel directions and equal intensities.

The MRI apparatus includes a main magnet forming a static magnetic field in a bore, and a gradient coil assembly which forms a magnetic field gradient in the static magnetic field and includes a plurality of shim trays arranged therein at a predefined interval and at least one first shim token provided between the shim trays.