Method for homogenizing a magnetic field profile of a superconductor magnet system

A method for homogenizing a magnetic field profile of a superconductor magnet system having a cryostat with a room temperature bore, a superconductor bulk magnet contained in the cryostat and arranged coaxially with the room temperature bore, and a cryogenic cooling system adapted for cooling the superconductor bulk magnet, wherein the superconductor bulk magnet comprises at least three axially stacked bulk sub-magnets that, in an initial state, carry respective initial currents with relative proportions according to an initial distribution scheme, and that provide an initial magnetic field profile, the method comprising:

• independently controlling a temperature of each bulk sub-magnet with the cryogenic cooling system to provide different respective temperatures to the sub-magnets and thereby provide the sub-magnets with different relative currents such that a first subset of the bulk sub-magnets has at least 99% relative magnetic saturation, and a second subset of the bulk sub-magnets has at most 95% relative magnetic saturation;
• mapping an initial magnetic field profile of the superconductor bulk magnet to determine a homogeneity thereof;
• and
• controlling a relative heating power and/or a cooling power provided to the first and second subsets of the bulk sub-magnets by the cryogenic cooling system without measuring the temperatures of the bulk sub-magnets so as to change the respective currents of the bulk sub-magnets to increase a homogeneity of said field profile.