Design of superconducting shim coils for an open bipanar MRI system using IBEM

An efficient design method of shim coils for an open bipanar superconducting magnetic resonance imaging (MRI) system is proposed, using an inverse boundary element method (IBEM). This design method first discretizes the shim coil space into some small flat triangular elements. By formulating the magnetization distribution by discrete current density, an objective function is constructed to evaluate the minimum error between axial magnetic field and desired magnetic field. In particular, the self-induction is added into the objective function which is used to adjust the deviation from the ideal target field. Finally, the well-known stream function method is commonly used to map the current density into wires. The algorithm details have been exemplified through biplanar shim coil design examples in this paper. This method can be used for coils on arbitrary surface shapes.