Quenching of a no-insulation high-temperature superconducting magnet

We report details on the quenching incident of an 18 T high-temperature superconducting (HTS) magnet, which occurred in December 2020. It has been received that the no-insulation (NI) design of an HTS magnet is relatively safe in quenching. However, the NI design could not completely prevent the magnet from quenching and damaging the associated system. Due to significant vibrations and fast energy dissipation during quenching, the magnet and the detector components are seriously damaged. The manufacturer inspected the magnet after the incident and repaired it in the spring of 2021. The magnet showed stable and consistent performance after the repair. It is evident that the NI-HTS magnet still requires quench protection circuits to secure the magnet and associated system.