Optimal Design of HTS Main Split Magnet for 240MeV Proton Cyclotron Accelerator

The performance and miniaturization of the main split magnet generated isochronous magnetic field in the 240 MeV proton cyclotron aims to apply in Hefei ion medical center, needs to be improved using high-temperature superconducting (HTS) magnet technology. In this study, we reported the optimization method of the HTS main split magnet based on using particle swarm optimization (PSO) algorithm. In the optimization, the volume of HTS tape, the current density, and the maximally experienced electromagnetic stress were set as a convergence condition to the optimization of the main split magnet. The magnetic field accuracy in the proton beam acceleration plane is converged under 1 ppm. We also evaluated the spherical harmonic components of the error of the magnetic field to verify the quality of magnet optimization. Finally, we conducted the analysis of electromagnetic field stress based on a structural finite element method to screen out the optimal scheme for the design of the HTS main split magnet for 240 MeV proton cyclotron.