A method for charging a superconductor bulk magnet by field-cooling using a magnet charger system, wherein the magnet charger system comprises a background charger magnet and a field adjustment unit, wherein the superconductor bulk magnet comprises a bulk magnet bore, wherein the bulk magnet bore contains a sample volume, wherein the background charger magnet comprises a charger bore, wherein the superconductor bulk magnet is arranged within the charger bore, wherein the background charger magnet and the field adjustment unit are arranged radially outside the bulk magnet bore, and wherein the superconductor bulk magnet has a critical temperature T c; with the steps of: step a) the magnet charger system is charged, such that after this charging it generates a first magnetic field in the sample volume, wherein the superconductor bulk magnet has a temperature T, with T>T c; step b) the superconductor bulk magnet is cooled to a temperature T<T c; step c) the magnet charger system is discharged, what inductively charges the superconductor bulk magnet, such that the superconductor bulk magnet traps a second magnetic field in the sample volume; wherein before step a), a correlation between a magnetic field applied by the magnet charger system from outside the superconductor bulk magnet and a resulting magnetic field trapped by the superconductor bulk magnet is determined at least approximately in the sample volume (100, 550), and wherein in step a), the field adjustment unit is set such that the first magnetic field generated by the magnet charger system in the sample volume comprises a homogeneous magnetic field component and at least one non-homogeneous magnetic field component, wherein said at least one non-homogeneous field component is chosen, using said correlation, such that the second magnetic field of step c) has a higher homogeneity than the first magnetic field of step a) in the sample volume, characterized in that said correlation is chosen with a linear function for each applied non-homogeneous magnetic field component comprised in the first magnetic field and to be adjusted by the field adjustment unit, wherein each linear function is defined by a slope and an offset, and correlates the component strength value of the magnetic field applied with the component strength value of the magnetic field trapped for its non-homogeneous magnetic field component, and that determining said correlation (100, 550) includes at least determining the offset for each linear function by calculation and/or by measurement. wherein the magnet charger system comprises a background charger magnet and a field adjustment unit, wherein the superconductor bulk magnet comprises a bulk magnet bore, wherein the bulk magnet bore contains a sample volume, wherein the background charger magnet comprises a charger bore, wherein the superconductor bulk magnet is arranged within the charger bore, wherein the background charger magnet and the field adjustment unit are arranged radially outside the bulk magnet bore, and wherein the superconductor bulk magnet has a critical temperature T c; with the steps of: step a) the magnet charger system is charged, such that after this charging it generates a first magnetic field in the sample volume, wherein the superconductor bulk magnet has a temperature T, with T>T c; step b) the superconductor bulk magnet is cooled to a temperature T<T c; step c) the magnet charger system is discharged, what inductively charges the superconductor bulk magnet, such that the superconductor bulk magnet traps a second magnetic field in the sample volume; step a) the magnet charger system is charged, such that after this charging it generates a first magnetic field in the sample volume, wherein the superconductor bulk magnet has a temperature T, with T>T c; step b) the superconductor bulk magnet is cooled to a temperature T<T c; step c) the magnet charger system is discharged, what inductively charges the superconductor bulk magnet, such that the superconductor bulk magnet traps a second magnetic field in the sample volume; wherein before step a), a correlation between a magnetic field applied by the magnet charger system from outside the superconductor bulk magnet and a resulting magnetic field trapped by the superconductor bulk magnet is determined at least approximately in the sample volume (100, 550), and wherein in step a), the field adjustment unit is set such that the first magnetic field generated by the magnet charger system in the sample volume comprises a homogeneous magnetic field component and at least one non-homogeneous magnetic field component, wherein said at least one non-homogeneous field component is chosen, using said correlation, such that the second magnetic field of step c) has a higher homogeneity than the first magnetic field of step a) in the sample volume, characterized in that said correlation is chosen with a linear function for each applied non-homogeneous magnetic field component comprised in the first magnetic field and to be adjusted by the field adjustment unit, wherein each linear function is defined by a slope and an offset, and correlates the component strength value of the magnetic field applied with the component strength value of the magnetic field trapped for its non-homogeneous magnetic field component, and that determining said correlation (100, 550) includes at least determining the offset for each linear function by calculation and/or by measurement.