High Field MgB2 Strands for High Energy Particle Colliders

Superconductor technologies in support of magnets are needed for use in accelerators, storage rings and charged particle beam transport systems. Magnesium diboride (MgB2), as an emerging superconductor material, offers the possibility of fabrication into multifilament strand from inexpensive starting materials using conventional metalworking processes. This project will development improved MgB2 superconductors with high critical fields and high at-field critical current density. Significant progress has been recently made for advancing the properties of MgB2, however current wires are characterized by upper critical and irreversibility fields that are too low, and most directly, critical currents that are too low in the 12 Tesla regime. This project will address these problems. The Phase I project fabricated wires with nano-powder additions for improving flux pinning and current density. Nano-ceramic, refractory metal, and metallic oxide powders were investigated. Strands doped with either Zr-based powders or SiC were fabricated for improving critical current and upper critical fields. A third class of strands was fabricated with custom nano-powders for improving current density. Powder processing techniques were varied to optimize strand performance. The Phase II project will fabricate MgB2 wires with improved in-field current densities, enhanced critical fields and increased connectivity. It will investigate making wires with specific classes of nano-powder additions to improve properties. Finally, a prototype solenoid coil wound with an optimized MgB2 conductor developed in this program will be fabricated. Commercial Applications and other Benefits as described by the awardee: The wire samples developed under this program will have wide ranging benefits for commercial applications such as MRI systems, power utility transformers, generators, motors and military applications.