Optimization of the magnetic field in the SK1000 central region model magnet

Abstract This study presents a design scheme for a central region model magnet, based on a high-intensity compact cyclotron. The objective is to ensure the long-term stable production of therapeutic radionuclides such as 211 At and 225 Ac, while maintaining reasonable construction and operational costs. In-depth research into the design principles and core parameters of the CRM (Central Region Model) cyclotron magnet system, guided by the concept of isochronous magnetic field design, enabled the optimization of the magnet's dimensions and magnetic field distribution. The optimization results show that the magnet system meets the acceleration and focusing requirements of the particle beam, effectively prevents particles from entering dangerous resonance regions, and aligns with the theoretical requirements of isochronous magnetic fields. This method keeps the error between the calculated magnetic field and the theoretical design field within 5 Gauss, meeting the expected physical design standards.