Passive shielding design for ultra-high field MRI superconducting magnets using an integral operation with nonlinear iteration

Passive shielding is a feasible approach to constrain the strong magnetic fluxes in ultrahigh field MRI superconducting magnets. However, an in-depth investigation of the passive shielding design is not well discussed in the literature and notably lacks nonlinear optimization design/analysis methods for this practice. This work developed a computation algorithm for passive shielding design, which uses an integral operation with nonlinear iteration. An exemplification for shielding a 9.4T whole-body MRI superconducting magnet showed the significant advantages of the proposed method over commercial packages. The optimized passive shielding scheme will be used in our future magnet engineering projects.