Speaker
Description
In the manufacture of Nb3Sn coils, the react-and-wind (R&W) method, which uses heat-treated wire to manufacture coils, has advantages, such as no need for heat treatment of the coil. In the R&W method, it is necessary to consider the degradation of the critical current due to Nb3Sn strain, including strain due to winding. Recently, we demonstrated the fabrication of R&W coils with a small bending radius of 55 mm minimum using a polyvinyl formal-coated CuNb-reinforced Nb3Sn wire. Although small bending radius increases the bending strain, we have shown that it is possible to fabricate coils without degradation by the strain control. Strain management includes windings that do not exceed irreversible strains and taking into account the effects of strain distribution within the wire, such as bending strains. As a next step, we have demonstrated the fabrication of a racetrack coil using the R&W method as a demonstration of strain management. The racetrack coil has straight sections and has both the same and opposite bends in the same coil relative to the heat treatment bend. In this presentation, the fabricated racetrack coil and test results will be reported.
