Development of Magnesium Diboride for Near Term HEP Applications

Magnesium diboride (MgB2) is an emerging superconductor material, which offers the possibility of fabrication into multifilamentary strands from inexpensive starting materials using conventional metalworking processes. However, in order to be useful for high energy physics (HEP) applications, several improvements will be required. This project will develop technology to increase the in-field Jc, filling factor, filament count, and stability, the most relevant improvements for near term accelerator-related applications. Phase I successfully fabricated a 54 + 7 filament strand with good properties, extruded a 19 filament strand, fabricated multifilament strands with more conductive outer sheaths, improved fill factor by 50%, and increased mid-field performance of MgB2 strands using SiC additives. In order to develop MgB2 strands for HEP applications, Phase II will increase: (1) the filament count to 74, by investigating both CTFF-route and seamless tube niobium barriers; (2) the SC fill factor, with a goal of fabricating strands with a 30% fill factor; (3) strand stability, through the investigation of more conductive outer sheaths; and (4) Jc performance in the 3-5 T regime, through methods to improve connectivity and densification, and through the introduction of dopants. Commercial Applications and other Benefits as described by the awardee: In addition to the application to HEP, an improved MgB2 superconductor material should accelerate the wire being developed for other commercial applications, such as MRI systems, power utility transformers, generators, motors and military applications