Study of Nb3Sn strands and cables for fermilab's common coil dipole models

Fermilab is developing 10–12 T superconducting dipole magnets for future accelerators based on Nb3Sn conductor. Within the High Field Magnet Project, a common coil design was chosen for magnet R&D using the react & wind approach. Based on cable studies in which a variety of designs were tried and tested using inexpensive ITER strands, a 41-strand cable was used for a racetrack coil, whereas a 60-strand cable was preferred for the common coil model. Multifilamentary Nb3Sn strands 0.7 mm in diameter to be respectively used in the racetrack coil and the common coil model were purchased from OST (Modified Jelly Roll technology) and IGC (Internal Tin technology). They are herein characterized by Ic, n-value, residual resistivity ratio, and magnetization. Results of cabling and bending degradation are also presented.