Nb3Al prototype conductor for the transmission line magnet

The Very Large Hadron Collider (VLHC), under consideration for construction at Fermilab in the next 1-2 decades, is a 100 TeV cm pp collider. A major cost driver is the magnet. R&D is underway on several possible magnet designs. A low-field (2T) superferric magnet, sometimes called a transmission line magnet, may be the most cost-effective route to the VLHC. Although NbTi is now the cheapest superconductor measured in cost/kA-meter, Nb₃Al has the potential advantage that it remains superconducting at higher temperature. It may be particularly suited to the single “turn” and long straight lengths of the transmission line design. The combination of the simple magnet design and the higher strain tolerance than e.g. Nb₃Sn allows a simple process of cable fabrication, reaction, and magnet assembly. This higher strain tolerance is an advantage for splicing in the field. Sumitomo Electric Industries is producing an Nb₃Al conductor for the Fermilab low-field magnet program