A 42-cm bore superconducting coil using pre-reacted Nb3Sn

A superconducting magnet being built for the Francis Bitter National Magnet Laboratory Hybrid III system will contain both niobium-titanium and Nb₃Sn conductors in two separate coils later joined in a common assembly. Prereacted Nb₃Sn will be in layer-wound coil. A description is given of the coil winding equipment and process used for the proposed 42-cm-bore coil to be wound with 8 layers of high-field conductor and 10 layers of low-field conductor. Each layer will contain about 60 turns. The outside diameter will be 62 cm, and the length 57 cm. When operated at 1.8 K with 2300 A, it will add 4 T to the 9.3 T from a NbTi magnet which surrounds it.