Transition Crossing by Means of Stable Islands

The phenomenom of transition energy crossing might generate adverse effects to the quality of charged-particle beams in circular accelerators that is hard to avoid, and has been known to introduce potentially adverse disturbance to the longitudinal dynamics of a beam of charged particles. A novel method to cross the transition energy using non-linear magnets is simulated in this project on a realistic lattice of the CERN Super Proton Synchrotron (SPS). Through scans of the non- linear magnet parameters, two approaches to the solution are proposed which might be suitable for bringing the beam through the transition process. However, tight constraints on the beam result in significant beam-size growth when using these configurations and risk of the process being ineffective. The first approach maximises the transition energy difference to minimise the effects near transition. It has an energy difference of 0.118 GeV but a large emittance growth (beam size) of 749\%. The second approach minimises the emittance growth, it gives an energy difference of 0.052 GeV and 150\% emittance growth. These results demonstrates the feasibility of the method, identifies the limitations and further work to minimise the emittance growth.