The 36-T Series-Connected Hybrid Magnet System Design and Integration
The system integration of a 36 T high field resistive-superconducting hybrid magnet system which will be used primarily for NMR studies is being finalized at the National High Magnetic Field Laboratory in Tallahassee, Florida. The hybrid magnet consists of a 23 T resistive insert coil set nested inside of a 13 T superconducting coil wound with high JC Nb3Sn/Cu cable-in-conduit conductor. The resistive and superconducting coils are connected electrically in series and operate at 20 kA. The combined system will enable 1-ppm level uniformity in a 1 cm DSV for condensed-matter NMR at a record level of 1.53 GHz. The resistive insert has four concentric Florida-Bitter coils and operates at 14 MW. The superconducting outsert operates with forced flow supercritical helium at 4.5 K and 3.5 bar. The superconducting protection system consists of two fully independent circuits, one employing voltage averaging comparisons between winding layers and the other a voltage comparison with a co-wound coil. Initial magnet testing of the resistive coils has been completed. The superconducting cold mass has been cooled to 4.5 K and the system is being prepared for combined hybrid magnet testing.