First Test of a Full Length Nb3Sn Sextupole Coil in a Mirror Structure for the FECR Ion Source

The new Nb
₃
Sn superconducting magnet system for a 45 GHz electron cyclotron resonance (ECR) ion source is under development in the Institute of Modern Physics (IMP). The full-length sextupole coil is wound by a single Nb
₃
Sn round wire. And due to the complicated technology process and the stress sensitivity, this coil is indeed a great technical challenge. In order to test the performance of the individual sextupole coil, a sextupole magnetic mirror structure based on the bladder and key technology is utilized. This paper presents the mechanical design of the mirror structure along with fabrication details, the room temperature assembly, and the first test results, respectively.