Abstract
To develop low cost Nn3Sn coils, we examined coil fabrication through the react and wind (R&W) technique by narrowing down the target to relatively big bore magnets for industrial applications. We first carried out various strain evaluations for the annealed Nb3Sn wire. Grasping the characteristics, we set up the allowable strain condition for handling the annealed wire. Using our internal-tin route wire, which has high cost performance, the wire was primarily reacted, then we coated it with cheap formal insulation while controlling the strain applied to the wire and then wound it to Nb3Sn coils. As a result of evaluating them, we succeeded in passing a current of 284A for the 23 layers of small-scale coil, which is equivalent to the case of short-length wires, and achieved a maximum field of 6.7T. We also succeeded in generating a maximum field of 9.5T for a commercial scale coil. As a result, we were able to demonstrate that the wire doesn't degrade and we were able to fabricate the coil through the R&W technique if the tensile and bending strain were securely controlled.
