Post-Quench electromechanical analysis of 1.5 T whole body clinical MRI system

A 1.5 T superconducting magnet has been designed for the whole-body clinical MRI scanner. The stored energy (∼4.5 MJ) of the magnet if released during a quench, can adversely affect the coil by raising its temperature and the associated voltage across the coil. Any quench in the MRI magnet induces an eddy current on various components of the magnet system such as bobbin, thermal radiation shield, etc. A passive quench protection scheme has been designed and simulated for the MRI magnet. The hot-spot temperature and the peak voltage in the magnet respectively are 136 K and 2.15 kV. The quench induced eddy current and the associated mechanical stresses have also been simulated for the various components. The peak density of the eddy current on the magnet bobbin and the thermal radiation shield are 375.5 A/cm² and 2316 A/cm² respectively. Whereas the peak mechanical stresses are 40.48 MPa and 11 MPa for the bobbin and the thermal radiation shield respectively. This paper briefly discusses the quench protection scheme, quench-induced eddy current and its associated mechanical stresses on various components of the magnet system.