Design, Simulation and Test Results of Quench Protection System for a 13-T Twin-Aperture Superconducting Dipole Magnet

On the basis of the successful development of a high field dipole magnet named LPF1-U, which reached a peak field of 12.47 T in 2021, the new magnet LPF3 with an expected field of over 13 T in the two 50-mm apertures has been designed and fabricated at IHEP. The magnet is developed in a common-coil configuration with six flat racetrack Nb
₃
Sn coils, as well as High Temperature Superconducting (HTS) insert coils in the center to further enhance the field to 16 T or more. The Nb
₃
Sn coils are designed to provide a 13 T main field at the operating current of 7580 A. The quench protection of the Nb
₃
Sn coils is significantly important and challenging because of the much larger magnet apertures (50 mm) and stored energy (2155 kJ). Finally, the method of CLIQ (coupling-loss induced quench protection system) together with varistor is adopted to accelerate the propagation of quench in the magnet and control the hotspot temperature. This article describes the design of the optimized quench protection scheme, the model and the simulation results. The experiment test results are also analyzed and discussed in this article.