Cyclotron with smooth energy variation

To increase the energy of the 120 cm cyclotron it has undergone modernization. The forming of radial falloff of the cyclotron magnetic field to the final radius of 53 cm in the magnetic field range from 5 to 16 KOe is provided by three concentric current windings positioned inside the vacuum chamber. For the vertical shift of the beam at initial radii use is made of a winding constituting a single-loop copper bus with a section of 15x4 mm and a current of 200 A. To shift the beam at final radii use is made of a winding with 1000 turns at a current of up to 1.5 A. The harmonic winding consists of four pairs of rectangular coils with 120 turns at a current of up to 8 A. The coils are positioned in the magnet pole gap through 90 deg intervals. With a modest correction of winding currents, at frequencies of 8.5-12.5 MHz the ion acceleration has been performed with smooth variation of energy in the following ranges of energies and currents correspondingly: protons 4.4 - 9.2 MeV, 30 μA; deuterons 8.8 - 15.8 MeV, 50 μA; helium ions 3 - 13.2 - 25.2 MeV, 10 μA; alpha-particles 17.6 - 31.6 MeV, 10 μA