Maintenance of Beam Stability in a Cyclotron with Isochronism Control for Several Types of Ions Using Rotary Shims

In order to increase the beam current, the CC-30/15 cyclotron designed to accelerate negative hydrogen ions to an energy of 30 MeV and negative deuterium ions to 15 MeV was upgraded. This modification resulted in an increase in the channel diameter in the cyclotron poles and a change in the elements of the central region of the magnet. To adjust the main cyclotron magnet to these conditions, 3D calculations were carried out to ensure stable and isochronous ion acceleration to the final energy. Particular attention was paid to the maintenance of stability in the presence of the 2nd harmonic of the magnetic field from the rotary shims in the modes of hydrogen and deuterium ion.