A 17 T NbTi-Nb/sub 3/Sn superconducting magnet with low-purity holmium core

A 14-T NbTi-Nb/sub 3/Sn superconducting magnet system with 31-mm bore has been constructed and tested. The magnet system consists of three coils one of NbTi and two of Nb/sub 3/Sn. Two different cross sections of Nb/sub 3/Sn wire constructed using the bronze method were chosen for the outer Nb/sub 3/Sn coil of 80-mm bore, and an (NbTi)/sub 3/Sn wire made by the high-tin-content Nb tube method was used to build the inner Nb/sub 3/Sn coil. The NbTi-Nb/sub 3/ magnet system has successfully achieved a 14.42 T central field at 4.2 K. To obtain a higher magnetic field, a pair of low-purity holmium cores of 25-mm diameter were used. The test of the NbTi-Nb/sub 3/Sn magnet with the holmium cores shows that the central field increases from 14 T to 17 T at 4.2 K.<
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