Monte-Carlo Quench Analysis for an HTS NI Head MRI Magnet Undergoing Sudden Discharge

<p dir="ltr">Presented at the 33rd International Symposium on Superconductivity</p><p dir="ltr">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.</p><p dir="ltr">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.</p><p dir="ltr">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.</p><p dir="ltr">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.</p>