C235-V3 cyclotron for a proton therapy center to be installed in the hospital complex of radiation medicine (Dimitrovgrad)

Proton therapy is an effective method of treating oncologic diseases. In Russia, construction of several centers for proton and ion therapy is slated for the years to come. A proton therapy center in Dimitrovgrad will be the first. The Joint Institute for Nuclear Research (Russia) in collaboration with Ion Beam Application (IBA) (Belgium) has designed an C235-V3 medical proton cyclotron for this center. It outperforms previous versions of commercial IBA cyclotrons, which have already been installed in 11 oncologic hospital centers in different countries. Experimental and calculation data for the beam dynamics in the C235-V3 medical cyclotron are presented. Reasons for beam losses during acceleration are considered, the influence of the magnetic field radial component in the midplane of the accelerator and main resonances is studied, and a beam extraction system is designed. In 2011–2012 in Dubna, the cyclotron was mounted, its magnetic field was properly configured, acceleration conditions were optimized, and beam extraction tests were carried out after which it was supplied to Dimitrovgrad. In the C235-V3 cyclotron, an acceleration efficiency of 72% and an extraction efficiency of 62% have been achieved without diaphragming to form a vertical profile of the beam.