Simulation Study of the Space Charge Limit in Heavy-ion Synchrotrons

Abstract

The SIS100 synchrotron as a part of the new FAIR accelerator facility at GSI should be operated at the "space charge limit" for light and heavy ion beams. Beam losses due to space charge induced resonance crossing should not exceed a few percent during a full cycle. The recent advances in the performance of particle tracking tools with self-consistent solvers for the 3D space charge forces now allow us to reliably identify low-loss areas in tune space, considering the full 1s (160'000 turns) accumulation plateau in SIS100. A realistic magnet error model, extracted from precise bench measurements of the SIS100 main dipole and quadrupole magnets, is included in the simulations. Previously such beam dynamics simulations required non-self-consistent space charge models. By comparing to the self-consistent simulations results we are now able to demonstrate that the predictions from such faster space charge models can be used to identify low-loss regions with sufficient accuracy. The findings are applied by identifying a low-loss working point region in SIS100 for the design FAIR beam parameters. The bunch intensity at the space charge limit is determined. Several counter-measures to space charge are proposed to enlarge the low-loss area and to further increase the space charge limit.