Superconducting Characteristics of Nb<sub>3</sub>Sn Cables Stranded with Ultra-fine Wires

We are developing A15 cables made of ultra-fine wires for react-and-wind （R&W） magnet technology. Recently, we fabricated a bronze processed multifilament Nb3Sn wire with diameter 50 µm. also prototype cable by stranding 19 testing. In this study, the transport critical current（Ic） was measured at 4.2 K and under an external field up to 18 T. The Non-Cu current density（Jc） calculated from Ic results. For measurements, wound on glass fiber reinforced plastic（GFRP） cylinder bobbins after heat treatment in straight geometry replicate R&W process. Four GFRP different diameters were prepared investigate bending limit cable. temperature（Tc） magnetization properties magnetic property measurement system Quantum Design.