Study on $\hbox {Nb}_{3}\hbox {Sn}$ Superconducting Coil With Ceramic Former

The Al₂O₃ machinable ceramic material, which has excellent insulation property and good thermal conductivity at low temperature, was used to make a coil former of a Nb₃Sn superconducting coil. Multifilament Nb₃Sn superconducting wire was wound on the ceramic former to form a Nb₃Sn superconducting coil. Afterwards, the coil was heat treated in vacuum, impregnated, and solidified. Finally, the coil was placed into a special cryostat to exam the critical current of the coil. The test results show that the operation current of the coil is no less than 500 A under 4 T background field. The coil can be charged at ramp rate of 10 A/s without quenching.