Zhang, X.H. JACoW Publishing Geneva, Switzerland 2673-5482 978-3-95450-212-7 10.18429/JACoW-CYCLOTRONS2022-THPO016 English 342-343 cyclotron acceleration proton focusing permanent-magnet Contribution to a conference proceedings 2023 2023-10 https://doi.org/10.18429/JACoW-CYCLOTRONS2022-THPO016 https://jacow.org/cyclotrons2022/papers/thpo016.pdf This paper introduces the design and analysis of 230 MeV cyclotron magnet of the proton therapy system. The magnet is an important part of the 230 MeV cyclotron, which can supply proton beam for the therapy terminal. The magnetic field calculation and modification has been done, and the isochronous error of the magnetic field is less than 0.2%. Meanwhile, the thermal analysis of the coil has been calculated by the empirical formula.