Production and Operation of a 15 T ${\rm Nb{\hbox{-}}Ti/Nb}_{3}{\rm Al}$ Hybrid Magnet System Powered by a Single Power Supply

We have recently developed a thin-type Cu clad stabilized Nb
₃
Al flat-wire which can be more densely wound into a coil. Using this flat-wire we have upgraded an existing 14 T Nb-Ti/Nb
₃
Sn magnet with a ¿ 30 mm clear bore, by replacing the inner coil, to a compact 15 T Nb-Ti/Nb
₃
Al magnet. The Nb
₃
Al inner coil was connected in series with the Nb-Ti outer coil and excited by a common power supply to generate 15 T in a ¿ 40 mm clear bore, after a training of Nb-Ti coil. The resultant higher field and wider space will be used for critical current measurements of various superconducting wires being developed in NIMS.