The Beam Bunch Effects in the Circular Isochronous Cyclotron

Numerical modelling calculation results for the acceleration process in an isochronous cyclotron and its influence on longitudinal size of the beam are presented. Two possible modes of beam bunching in a circular isochronous cyclotron with a double accelerating system are discussed. Two dee systems operate at frequencies differing by an integer and with dee voltage amplitudes approximately equal, In the first case the accelerated beam phase is shifted from the minimum at the curve ΔE(ψ) to the maximum value in the non-isochronous acceleration region. In this case effective bunching is observed. In the other version bunching effects are produced at the ion bunch input into the additional dee which is connected to the main one. Ultra-short accelerated particle bunches obtained by this method can be successfully used in time-of-flight experiments.