Particle dynamics in a DTL for high intensity heavy ion beams for inertial fusion

Abstract

Multi-particle beam dynamics calculations in presence of large beam currents have been carried out for a heavy ion Drift Tube Linac (DTL), in the framework of a European study group on Heavy Ion Driven Inertial Fusion (HIDIF). Linac design parameters were determined for high transmission and low emittance growth; then statistical errors as well as on-axis mismatch were added. The influence of field errors and different mismatch combinations on beam halo formation and emittance increase has been studied numerically, e.g. phase and amplitude jitters of the rf field, small changes of quadrupole gradients, mismatch of beam bunches at linac input. For proper ring injection, a transfer line and a bunch rotation cavity have to be inserted between linac and storage rings. The energy spread reduction after bunch rotation has been investigated both numerically and analytically, comparing an ideal case with a more realistic one which includes rf errors and mismatch.