Design and test of a DCT curved superconducting dipole magnet for ion-therapy

A curved superconducting dipole magnet based on Discrete Canted-Cosine-Theta (DCT) coil with magnetic field of 2.9 T, bend radius of 0.8 m, and bend angle of 90° for next- generation of compact ion-therapy treatment facility has been designed and tested. The curved dipole is comprised of eight layers of DCT coils embedded in the formers wound with NbTi wires, featuring compact ends and higher excitation efficiency. This paper presented the main mechanical structure design, analysis, and measurements of the curved DCT magnet. A curved superconducting dipole magnet based on Discrete Canted-Cosine-Theta (DCT) coil with magnetic field of 2.9 T, bend radius of 0.8 m, and bend angle of 90° for next- generation of compact ion-therapy treatment facility has been designed and tested. The curved dipole is comprised of eight layers of DCT coils embedded in the formers wound with NbTi wires, featuring compact ends and higher excitation efficiency. This paper presented the main mechanical structure design, analysis, and measurements of the curved DCT magnet. Based on the finite element method (FEM) model with ANSYS, a detailed analysis of the DCT magnet mechanical behavior during cool-down and excitation has been studied. Finally, the magnetic field and strain measurements are measured from a cryogenic test bath cooled with liquid helium, during which the magnet reached 70% of the expected goal. The reason for magnet failure based on the strain measurement results is also reported in this paper.