Design Optimization of Combined Function Accelerator Magnet Using Truncated Singular Value Decomposition

The Japan Proton Accelerator Research Complex (J-PARC) is a world-class accelerator facility for particle and nuclear physics experiments such as the rare kaon decays experiment (KOTO), the T2K long-baseline neutrino experiment, and future projects such as COMET. A new stretcher ring (SR) comprising a combined function superconducting magnet is proposed to run all of the facilities at the same time, which can improve beam efficiency and increase operating time. In order to achieve the field quality requirements on the magnet aperture, it is critical to identify an optimum pole shape. Dipole, quadrupole, and sextupole fields are required for the combined function magnet. To find the best design parameters for this analysis, we employed singular value decomposition. The singular value decomposition (SVD) technique resulted in a solution to the desired parameters and a quick process to obtain a 2D pole profile.