Research On Magnet Design Of Cyclotron For Proton Therapy

As a new radiotherapy for carcinomas, proton therapy has been developing. High-energy proton for treating cancel has such advantages as more accurate thanγray and X ray, less injury to normal tissues, wider adaptations, better results and less complications etc. Proton therapy has become major trend for future radiotherapy. The accelerator is the most important part of proton therapy equipments. So the research for accelerator is of great significance.This paper researches the method of designing cyclotron main magnet for proton therapy, providing reference value for the establishment of the proton cyclotron. The dissertation consists of the main four parts, as follows:Firstly, the purpose and the trend of proton therapy are presented. Compared with other conventional radiotherapy, the characteristic of proton therapy is analyzed. The whole proton therapy system is introduced, and the functions, characteristics, requests of separate parts are analyzed.Secondly,the structure of cyclotron and its principle are introduced, as well as the characteristic of the isochronous cyclotron is analyzed. Using the theory of beam dynamics, the closed orbit of proton is researched and then the relation between correction of pole angle and phase shift is calculated.Thirdly, main magnet design process of 250MeV cyclotron for proton therapy is researched in detail. Preliminary parameters of the main magnet are calculated by the program according to the method previously mentioned.Finally, 2D and 3D analysis of the main magnet are researched by using the FEA software ANSYS and magnetic field distribution of the preliminary model can be analyzed. Using the beam dynamics program, the energy and phase shift graph of the model are plotted. The ideal size of the main magnet can be calculated after several optimization.