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 at the Institute of Electrical Engineering, Academia Sinica. The magnet system consists of three coils, one of NbTi and two of Nb/sub 3/Sn coils. Two different cross section Nb/sub 3/Sn wires using the bronze method made by Baoji Institute of Non-Ferrous Metal were chosen for the outer Nb/sub 3/Sn coil with 80 mm bore and a (NbTi)/sub 3/Sn wire using the high tin content Nb tube method was used to build the inner Nb/sub 3/Sn coil. The NbTi-Nb/sub 3/Sn magnet system has successfully achieved 14.42 T central field at 4.2 K. In order to obtain higher magnetic field, a pair of low-purity Holmium cores of 25 mm in diameter were used for the NbTi-Nb/sub 3/Sn magnet system. The test of the Holmium cores with the NbTi-Nb/sub 3/Sn magnet shows that the central field increases from 14 T to 17 T at 4.2 K