Magnetic moment arrangement calculation method for magnetic field adjustment, magnetic field adjustment device and program

A magnetic field adjustment device comprising:

• a magnetic field distribution measurement portion that measures a magnetic field distribution of a predefined evaluation region in a magnetic field generation device including a magnetic field adjustment mechanism which adjusts a static magnetic field by using a magnetic moment disposed therein;
• an arrangement computation portion that computes arrangement of the magnetic moment for correcting an error magnetic field distribution which is a difference between the measured magnetic field distribution and a predefined target magnetic field intensity of the evaluation region;
• and
• a low-order/high-order determination portion that divides each eigenmode of a magnetic field generated by the magnetic field generation device into a low-order mode which is an eigenmode group from the first of eigenmode numbers assigned to respective eigenmodes in the magnitude order of singular values to an eigenmode number specified by a first threshold value, and a high-order mode which is an eigenmode group with an eigenmode number more than the first threshold value,
• wherein the arrangement computation portion decomposes the error magnetic field distribution into components of respective eigenmodes obtained through singular value decomposition, and combines correction of a component of the low-order mode with correction of a component of the high-order mode so as to calculate the arrangement of the magnetic moment for approximately correcting the error magnetic field distribution, and
• wherein a correction amount of the component of the high-order mode is smaller than a correction amount of the component of the low-order mode.

A non-transitory computer readable medium storing a program, which when executed by a computer, causing the computer to function as:

• a magnetic field distribution measurement portion that measures a magnetic field distribution of a predefined evaluation region in a magnetic field generation device including a magnetic field adjustment mechanism which adjusts a static magnetic field by using a magnetic moment disposed therein;
• an arrangement computation portion that computes arrangement of the magnetic moment for correcting an error magnetic field distribution which is a difference between the measured magnetic field distribution and a predefined target magnetic field intensity of the evaluation region;
• and
• a low-order/high-order determination portion that divides each eigenmode of a magnetic field generated by the magnetic field generation device into a low-order mode which is an eigenmode group from the first of eigenmode numbers assigned to respective eigenmodes in the magnitude order of singular values to an eigenmode number specified by a first threshold value, and a high-order mode which is an eigenmode group with an eigenmode number more than the first threshold value,
• wherein the arrangement computation portion decomposes the error magnetic field distribution into components of respective eigenmodes obtained through singular value decomposition, and combines correction of a component of the low-order mode with correction of a component of the high-order mode so as to calculate the arrangement of the magnetic moment for approximately correcting the error magnetic field distribution, and
• wherein a correction amount of the component of the high-order mode is smaller than a correction amount of the component of the low-order mode.