Fig. 1. Schematic diagram of basic parameters of double-spoke cavity

Fig. 2. Flow chart of parameter optimization

Fig. 3. Distribution of electric field on the internal surface and axis withE_p/E_acc =4.1

Fig. 4. TTF distribution of DSR

Fig. 5. MP’s position and SEY simulation of different materials

Fig. 6. Simulation calculation of coupler antenna and Q_e

Fig. 7. The mechanical structure of DSR

Fig. 8. Stress distribution of DSR and cambered reinforcing ribs

Fig. 9. LFD coefficient of DSR

Fig. 10. Mechanical intrinsic frequency and vibration mode of DSR

Fig. 11. Decomposition of the earth magnetic field

Fig. 12. Design of magnetic shield and distribution of residual magnetic field in axis of DSR

Fig. 13. Welding diagram of DSR