Monte-Carlo Quench Analysis for an HTS NI Head MRI Magnet Undergoing Sudden Discharge
Presented at the 33rd International Symposium on Superconductivity
The work focuses on developing and analyzing the sudden discharge performance of a High-Temperature Superconducting (HTS) No-Insulation (NI) MRI magnet specifically designed for head imaging. This innovative magnet, developed at the Robinson Research Institute and funded by the National Institutes of Health (NIH), features a unique upright configuration, allowing patients to sit comfortably during imaging. The magnet comprises 23 double pancake HTS coils, offering a cryogen-free design with a 1.5 T uniform imaging field and precise temperature and current specifications.
Key challenges include ensuring the magnet can discharge rapidly for safety, reducing the magnetic field from 1.5 T to below 0.05 T within 20 seconds. A critical tuning parameter is the contact resistivity between turns of the HTS tape. The work employs a comprehensive multi-physics model to simulate electromagnetic, thermal, and structural behaviors during discharge.
Monte Carlo simulations address manufacturing variability, such as differences in epoxy composition and tape tension, by running 100 discharge scenarios with segment-wise resistivity variations. These simulations highlight the impact of both intra- and inter-coil variability on field reduction, temperature distribution, and voltage behavior, ensuring robust performance even under imperfect manufacturing conditions.
The results show that while most simulations meet the discharge specifications, some variability in performance is observed due to segment-level resistivity differences. The study concludes that the HTS MRI magnet’s design is robust, with acceptable performance under real-world manufacturing constraints, providing critical insights for future coil development and operational safety standards. This work significantly advances the feasibility of compact, high-performance MRI systems for specialized medical applications.
