PROBLEM TO BE SOLVED: To achieve high magnetic homogeneity even when a quantity of a magnetic material piece capable of being arranged to each of positions on a shim tray is limited.SOLUTION: A magnetic homogeneity adjustment method includes: a step of measuring a distribution of a static magnetic field generated by a static magnetic field generator to calculate an error magnetic field between the distribution of the static magnetic field and a target magnetic field a step of individually calculating, while varying the target magnetic field in a predetermined magnetic field range, magnetic homogeneity reachable in the case of arranging magnetic material pieces to one or more of a plurality of positions on the shim tray a step of selecting a target magnetic field whose quantity of magnetic material piece of each position on the shim tray is equal to or lower than a predetermined upper limit value and whose reachable magnetic homogeneity is equal to or lower than a predetermined value a step 81 of setting a discrete error calculation magnetic field range including the selected target magnetic field, re-calculating reachable magnetic homogeneity while varying the target magnetic field when values capable of being taken as a quantity of a magnetic material piece are predetermined discrete values, and re-selecting a target magnetic field having minimum reachable magnetic homogeneity: and a step of taking arrangement of magnetic material pieces corresponding to the re-selected target magnetic field and their quantity as arrangement and quantity of magnetic material pieces to be arranged on the shim tray.SELECTED DRAWING: Figure 5COPYRIGHT: (C)2016,JPO&INPIT【課題】シムトレイの各位置に配置可能な磁性体片の量に制限があっても、高い磁場均一度を達成する。【解決手段】静磁場発生装置の生成する静磁場の分布を計測して、静磁場の分布と目標磁場との誤差磁場を算出する。シムトレイの複数の位置のうち1以上に磁性体片を配置した場合に到達可能な磁場均一度を、目標磁場を所定の磁場範囲で変化させながらそれぞれ算出する。シムトレイの各位置の磁性体片の量が所定の上限値以下であって、到達可能な磁場均一度が所定値以下である目標磁場を選択する。選択した目標磁場を含む離散化誤差演算用磁場範囲を設定し、磁性体片の量としてとり得る値が所定の離散的な値である場合に、到達可能な磁場均一度を目標磁場を変化させながら再度算出し、到達可能
