Fabrication and Assembly of the NHMFL 25 T Resistive Split Magnet

The NHMFL has developed a high-field split resistive magnet for use in far-infrared photon scattering experiments. The magnet includes four large scattering ports of elliptical shape at the mid-plane amounting to a total solid angle of 0.5 steradians of available user space. Such a magnet configuration results in unique design challenges being especially severe for the windings in the mid-plane region of the innermost coils. Consequently, the NHMFL developed, tested and employed a new technology called Split Florida-Helix. Next, the coil design of the split user magnet, to be operated at our own facility, has been completed in 2009. This user magnet consist of 5 resistive coils consuming a total of less than 28 MW of dc power and providing a flux-density of 25 T available to the user space. To meet the unique design challenges, Split Florida-Helix technology is used around the mid-plane of the two inner most coils and state-of-the-art Florida-Bitter technology is used for all the regular winding in all 5 coils.