FEA-Aided Design of a Powered Scattering Magnet at the NHMFL

Abstract

The NHMFL has completed the design of all major components of 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. 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 incorporated its newly developed technology called split Florida-Helix previously tested at the NHMFL with diverse working models. The user magnet, to be operated at our own facility, will consist of 5 resistive coils consuming a total of less than 28 MW of dc power and providing a flux-density of at least 25 T available at the center of the user space. All coils employ axial current grading for field optimization and stress management. Advanced finite element analysis (FEA) served as the essential tool guiding the design optimization of the overall system and the various components. This paper provides a systematic discussion of the critical features and techniques utilized in the complex model-based analysis and the authors present a variety of detailed FEA results and design parameters critical for the integration of the split Florida-helix in conjunction with the traditional Florida Bitter disc design.