Intensity and Bunch-Shape Dependent Beam Loss Simulation for the SIS100

We have studied the combined influence of magnet nonlinearities, space charge and bunch shapes consistent with different RF scenarios on the long-term loss in the planned SIS100 synchrotron of the FAIR project. The simulation is a 3D tracking with” frozen-in” space charge calculation employing the MICROMAP code. Comparing a one-harmonic RF scenario with an alternative double-harmonic scenario we find that for the same absolute beam loss roughly twice the number of particles can be stored in the double-RF system. Moreover, a barrier bucket RF scenario is found to be loss-free. This is due to the fact that loss is caused here by space-charge induced periodic resonance crossing, which is absent for the strictly flat bunch profile of the barrier case.

THE SIS100 RING

In the FAIR project [1] the SIS100 synchrotron [2] is composed of six super-periods made by 15 doublet focusing DF structures and 20 dipoles. The sc dipole magnet of Nuk-lotron type have apertures of . The length of the ring is 11/2 times the SIS18 circumference and the magnetic rigidity In Fig. 1 is shown the layout of the existing facility and the SIS100 in the new facility. Figure 1: FAIR project and SIS100