CYCLOTRON C235-V3 FOR DIMITROVGRAD HOSPITAL CENTER OF THE PROTON THERAPY

JINR-IBA C235-V3 isochronous cyclotronfor 1 st Russian hospital center of the proton therapyhas been assembled and tested. Shimming of the magnetic field, optimization of the acceleration modes and testing with the extracted proton beam were done in frame of this work. The paper presents experimental results of the beam dynamics in the accelerator. Proton transmission from radius 30cm to 103cm is 72% without beam cutting diaphragms. The extraction efficiency is 62%. This cyclotronis a substantially modified version C235-V3 of the IBA C235 serial cyclotron. C235-V3 has the improved extraction system which was constructed and tested. This system allows raise the extraction efficiency up to 77% from 50% in comparison with serial C235. Special mapping system (for Br-component) of the magnetic field was developed and constructed by JINR for the shimming of the Br-field in the middle plane of the cyclotron. Total efficiency of the machine is 45%. Further improvement of the parameters expected after final tuning of the cyclotronin Dimitrovgrad.