Radial-Longitudinal Coupling in Proposed RCNP Injector Cyclotron

For an injector cyclotron to a ring cyclotron proposed at RCNP, the second, third and fourth harmonic modes are used for the light ion acceleration. To accelerate ions in these harmonic modes without phase space deformation, it is necessary to investigate the effect of radial-longitudinal coupling. For single, two and three dee configurations, the beam behavior in radial phase space was studied numerically for each harmonic mode and dee angle. In the case of the second and third harmonic accelerations of protons with two dees, dee angles between 60 and 75 degrees are acceptable. The results are compared with 180-degree single dee and 40-degree three dees for the third harmonic mode.