Study on Magnets for Beam Transport System of SC200 Superconducting Proton Therapy Facility

The SC200 proton therapy facility is consisting of a superconducting cyclotron, a gantry treatment room and a fixed beam room. The proton beams are transported mainly with beam transport devices, such as dipole magnets, quadrupole magnets, and corrector magnets which lie on the beam transport line layout of which is based on the beam optics design. A series of dipole, quadrupole, and corrector magnets ultimately make high-quality transmission of proton beams possible. Dipole magnets are mainly for beams deflection, quadrupole magnets are for beam focusing, and corrector magnets for orbit correction of beams. This paper shows the design of such magnets for the beam transport line. Besides, main parameters of magnets are presented and magnetic analysis work is also illustrated in this paper. The magnetic fields of dipole and quadrupole magnets are measured by hall mapping system and rotary coil measuring system. The results show that the measuring results are a little worse than the simulation results. However, both methods can meet the design requirement and the basic trend is similar to each other.