Particle buncher with sinusoidal modulation for the axial injection system of the U-240 isochronous cyclotron

Use of buncher in the external injection system of the isochronous cyclotron is intended to enlarge the luminosity, which is especially important during acceleration of very low-current beams of the polarised and multicharged ions. Problems of two-gap particle bunching with sinusoidal modulation are considered. An optimal buncher arrangement, allowing for the energy spread in the source beam is determined. Calculation of buncher parameters is done for the axial injection system of the isochronous cyclotron U-240. The buncher application allows one to obtain compact bunches and enlarge the source efficiency by the factor of 50%