High Field MgB2 Strands for High Energy Particle Colliders

The DOE is seeking superconductor technologies in support of magnets for use in accelerators, storage rings, and charged-particle beam-transport systems. Magnesium diboride (MgB2), an emerging superconductor material, offers the possibility of fabrication into multifilamentary strand from inexpensive starting materials using conventional metalworking processes. This project will develop improved MgB2 superconductors with high critical fields and high at-field critical current density. In particular, this project will improve: (1) flux pinning and current densities, (2) Bc2 and irreversibility field, and (3) the related homogeneity for MgB2 superconductor wires. Phase I will investigate the fabrication of monofilament wires with metallic oxide additions, with metal hydride additions, and with ex situ nano-MgB2 powders for improving flux pinning,current density, and upper critical fields. An optimization of parameters (additive level, heat treatment parameters, powder processing conditions, purity, and stoichiometry) will be performed, followed by the fabrication of multifilament strands. Commercial Applications and other Benefits as described by the awardee: An improved MgB2 should have commercial applications in MRI systems, power utility transformers, generators, motors, and military applications. Additionaly, magnesium diboride strands with relatively high Tc (thermal margin) radiation tolerance may find other near-term accelerator applications in the winding of light-source wiggler and undulator magnets.