SYNCHROCYCLOTRON FOR EXTRACTING BEAMS OF VARIOUS ENERGIES AND RELATED METHOD

The present invention concerns a synchrocyclotron for extracting charged particles accelerated to any extraction energy (Ei) comprised between a low energy (E1) and a high energy (E2), the synchrocyclotron comprising a magnetic unit comprising N valley sectors and N hill sectors, and being configured for creating z-component (Bz) of a main magnetic characterized by a radial tune (vr) of the successive orbits different from 1 and comprised within 1 ± 0.1 for all values of the average radius (R), comprised between a low radius (R1) and a high radius (R2), corresponding to respective average radial positions of the charged particles at the low and high energies (E1, E2), The synchrocyclotron comprises a first instability coil unit (51) and a second instability coil unit (52) configured for creating, when activated by a source of electric power, a field bump of amplitude (ΔBz(R)) increasing radially. The amplitude of the field bump can be varied to reach the value of the offset amplitude (ΔBz0(Ri, vr)) at the average instability onset radius (Ri). The offset amplitude (ΔBz0(Ri, vr)) is the minimal amplitude of the field bump at the average instability onset radius (Ri) required for sufficiently offsetting the centre of the orbit of average instability onset radius (Ri) to generate a resonance instability with, a combination of harmonic 2 and gradient of harmonic 2, to extract the beam of charged particle at the average instability onset radius (Ri).