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.

This invention provides methods for fabricating a hard or soft magnet with tailorable magnetic and crystallographic orientations. Methods are disclosed to individually tailor three-dimensional voxels for selected crystallographic orientations and, independently, selected magnetic orientations with location specificity throughout a magnet. Some variations provide a method of making a magnet, comprising: providing a feedstock composition containing magnetic or magnetically susceptible materials; exposing the feedstock composition to an energy source for melting, thereby generating a first melt layer; solidifying the first melt layer in the presence of an externally applied magnetic field, thereby generating a magnetic metal layer containing a plurality of individual voxels; optionally repeating to generate a plurality of solid layers; and recovering a magnet comprising the magnetic metal layer(s), wherein the externally applied magnetic field has a magnetic-field orientation that is selected to control a magnetic axis and a crystallographic texture within the magnetic metal layer(s).

A sintered annular magnet with a radial orientation of a remanent magnetic field, including: a principal annular part made from a ferromagnetic material, that has a first degree of magnetic anisotropy in the radial direction; and an annular reinforcing part fixed to the principal part of the magnet, the reinforcing part being made from same ferromagnetic material as the ferromagnetic material forming the principal part, and that has a second degree of magnetic anisotropy in the radial direction, the first degree being higher than the second degree.

The disclosure provides a hybrid magnet structure which includes two dipole magnets assemblies arranged oppositely, and each dipole magnet assembly includes a permanent magnet, two iron cores, and a moveable magnetic field shunt element. The hybrid magnet structure is adapted to focus particle beams of different positions by applying an adjustable gradient magnetic field in the horizontal or vertical direction of the particle beam. By passing the charged particle beams through the gradient magnetic field established between the two dipole magnets, the aspect of focusing the charged particle beam is achieved. In addition, the intensity of the gradient magnetic field can be altered by adjusting the gap between the movable magnetic field shunt element and the permanent magnet, thereby controlling the particle beam size on a specific axis for different energies or masses of the charge particles.

A device is dynamically programmable to generate at least a first magnetic field during a first time interval, and at least a second magnetic field during a second time interval thereby causing the particles exposed to the change in the magnetic field to aggregate to a target region. The device is further dynamically programmable to switch between the first and second magnetic fields for any number of cycles. Optionally, the device includes a multitude of conductors that receive a first current during the first time interval to generate the magnetic field, and a second multitude of conductors that receive a second current during the second time interval to generate the second magnetic field. The second multitude of conductors may be substantially parallel to the first multitude of conductors. A controller disposed within the device is adapted to vary the frequency of switching between the first and second magnetic fields.

A magnet array (400) includes multiple magnet (411-420) rings and a frame. The multiple magnet rings are positioned along a longitudinal axis and coaxially with the longitudinal axis, wherein at least two of the magnet rings include mixed-phase magnet rings (411, 413) that are phase-dissimilar. The multiple magnet rings are configured to jointly generate a magnetic field along a direction parallel to the longitudinal axis of at least a given level of uniformity inside a predefined inner volume (430). The frame is configured to fixedly hold the multiple magnet rings in place.

A magnet array (700) includes multiple magnet rings (711-720) and a frame. The multiple magnet rings are positioned along a longitudinal axis and coaxially with the longitudinal axis, wherein at least one (712, 713, 719) of the magnet rings possesses rotational symmetry and has both a finite component of magnetization along an azimuthal (θ) coordinate, and a finite magnetization in a longitudinal-radial plane. The multiple magnet rings configured to jointly generate a magnetic field along a direction parallel to the longitudinal axis. The frame is configured to fixedly hold the multiple magnet rings in place.

A method of designing at least one coil for producing a magnetic field is disclosed. The method comprises: i) setting a performance target comprising: a target magnetic field, and at least two of a target power, a target resistance, a target size and/or weight, a target supply voltage or current, and a target inductance; ii) determining initial design parameters for the at least one coil; iii) modelling performance with the current design parameters to determine a simulated performance against each of the performance targets; iv) calculating a penalty function based on the difference between the simulated performance and the performance targets; v) modifying the design parameters in order to reduce the penalty function; vi) iterating steps iii) to v) until the penalty function or simulated performance has met an acceptance condition.

The disclosure provides a hybrid magnet structure which includes two dipole magnets assemblies arranged oppositely, and each dipole magnet assembly includes a permanent magnet, two iron cores, and a moveable magnetic field shunt element. The hybrid magnet structure is adapted to focus particle beams of different positions by applying an adjustable gradient magnetic field in the horizontal or vertical direction of the particle beam. By passing the charged particle beams through the gradient magnetic field established between the two dipole magnets, the aspect of focusing the charged particle beam is achieved. In addition, the intensity of the gradient magnetic field can be altered by adjusting the gap between the movable magnetic field shunt element and the permanent magnet, thereby controlling the particle beam size on a specific axis for different energies or masses of the charge particles.

An apparatus and method for dynamically stabilizing the fields in a permanent magnet assembly, including a nuclear magnetic resonance machine. One or more magnetically active elements affect the fields of the magnet assembly. A mechanism controls and changes the position(s) of the magnetically active element(s) to affect and adjust the magnetic field strength in the working volume of the assembly. A sensor provides a control signal indicating the status of the magnetic field strength, and an algorithm is executed for determining, based on the signal, the manner in which the adjustment should be made. The adjustment may be continuous and dynamic, and stabilization of the field may occur during operation of the permanent magnet assembly. The adjustments of the position of the magnetically active element stabilize the field without unduly degrading the field homogeneity, even for high homogeneity magnets.