Research On The Design Of Cyclotron Cavity Virtual Prototyping

Cyclotrons are widely used in fundamental researches in national defense, isotopes production, medical diagnosis and therapy. The RF system is the one of the most important component of the cyclotron. The cavities of the RF System used in cyclotrons have to provide accelerating voltage,whose working conditions for the performance is a great impact on cyclotrons. The tuning frequency and changed loading needs a fine-stability cavity to operate at satisfied conditions.Analysis of a 30MeV cyclotron cavity has been carried out. The influences on the RF resonant frequency, the quality value and the Dee voltage have been investigated into. The design method of the transmission line schematization has been compared with the large 3D electromagnetic code. Using 3D finite element method (FEM), the computing model is completed based in PC. The influence of the cavity mesh, the model construction and the symmetry condition method are discussed. The calculation results show that the resonant parameter can be adjusted by the cavity height,the tuning capacity,and the diameter of the stem. Numerical experiment results showed that this simple model has no obvious influence on the computing results. The difference between the computing values and the measuring results is allowable in practice so that the software based on FEM can be used to simulate the cavity with complex boundaries. The review of the work would help the conception and engineering design of the cavity.The research theme of this dissertation is about the cavity design of 100MeV intense beam H- Cyclotron. Emphasis is set on the method of cavity analysis and design. Two types of cavity model (the double-stem and the triangle-stem) are designed by the method based on FEM and performed with 3D electromagnetic codes to simulate the process RF experiment. The work can be used as a reference for the final design of the cavity of the 100MeV High-beam H- Cyclotron and their establishments.The method of periodically loaded 1/4 transmission in decreasing the cavity's volume is analyzed. With both the transmission line theory and numerical simulation methods, we obtained the cavity's performance and their application in the design of the RF cavity of the 100MeV cyclotron.