Optimization of the new sc magnetic structure design with a hybrid magnet*

In the development of the next generation Electron Cyclotron Resonance Ion Source, so far either a set of full NbTi or Nb3Sn magnets has been proposed to construct the magnet system. However, the single set of NbTi magnets may not be the optimum in terms of the field strength and configuration. An optimization of the new SC magnetic structure [1] with a hybrid magnet (NbTi and Nb3Sn) is being investigated. With the hybrid magnet and other minor changes the optimized new magnetic system is capable of producing field maxima of 9.0 T on axis and 4.1 T at the plasma wall, which are about 30 and 5 percent higher than the new SC magnetic structure to be built with a set of full NbTi magnets. In addition, the axial length of the optimized magnetic structure has been slightly shrunk resulting in a less bulky system. This new magnetic field profile is high enough for operation frequency up to 56 GHz. The design features and the preliminary stress analysis of the optimized new SC magnetic structure will be presented and discussed.