Research On Main Magnet Design Of Cyclotron Virtual Prototyping

Cyclotrons are widely used in fundamental researches in national defense, isotopes production, medical diagnosis and therapy. The research theme of this dissertation is about the main magnet design of 100MeV intense beam H-Cyclotron. Emphasis is set on the method of magnetic analysis and design. Two types of magnet model are designed by the method based on ANSYS. This research has reference value for the final design of the main magnet of 100MeV High-beam H-Cyclotron and their establishments. Firstly, the theory of cyclotron beam dynamics, which offers the important theoretical foundation, was introduced in this dissertation. The program COAMD programmed by ourselves to calculate beam dynamics was discussed. Some factors in FEM analysis with ANSYS of magnet were studied. First, 2D and 3D analysis were compared. Then the influence of the modeling of the periphery air and the minutiae, and the meshing of the magnet were discussed. When the symmetry conditions were applied in FEM, some defects of ANSYS in calculating the magnetic field at the symmetrical boundary were found, and an improving program FEM_AF_ANSYS was presented. The main parameters of the magnet, namely, the valley depth, valley angle, pole gap and coil shape, were changed to observe the variation of the magnetic field in the mid-plane. Their relations were summarized to help cyclotron magnet design and analysis. CMEF, software about magnetic design based on ANSYS, was developed. The software integrated three programs by ourselves, namely, calculating program with ANSYS language, FEM_AF_ANSYS and COAMD and simplifies magnetic design. Two types of magnet, separated-sector type and spiral-sector type, were designed using CMEF according to the parameter requisition of 100MeV intense beam H-Cyclotron. The size of magnet, the magnetic field distribution and value of beam dynamics calculation was given detailedly. The results of design met the requisition theoretically.