Proceedings of the XXIV Russian Particle Accelerator Conference 2014(RuPAC2014), Obninsk, Kaluga Region, Russia

The isochronous cyclotron DC-280 is intended to accelerate the ion beams with A/Z from 4 to 7 up to the energy 8 – 4 MeV/nucleon. The wide range of the magnetic field levels from 0.64T till 1.32T allows to make a smooth variation of the beam energy over the range ±50% from nominal. For operational optimization of the magnetic field the 11 radial and 4 pairs of harmonic correcting coils are used. The numerical formation of the magnetic field is carried out. The problems and solutions of DC-280 magnetic field design are described.