• P.J. Spiller, L.H.J. Bozyk, P. Puppel, J. Stadlmann
  GSI, Darmstadt

In order to achieve the goals of the FAIR project, the heavy ion beam intensities have to be increased by two orders of magnitude. Space charge limits and significant beam loss in stripper stages disable a continuation of the present high charge state operation. However, in the energy range of SIS18 and SIS100, the chosen intermediate charge state for uranium 28+, is lower than the equilibrium charge state. Thus ionisation processes due to collisions with rest gas atoms become the main issue with respect to potential beam loss. Therefore, the SIS100 design concept is focused on the goal to minimization the beam-rest gas interaction and consequently the beam loss by charge change: SIS100 is the first synchrotron which has been optimised for the acceleration of intermediate charge state heavy ion operation. Ionisation beam loss, desorption processes and pressure stabilization were the driving issues for the chosen system layout and for several technological approaches. Beside focusing the SIS100 design on this specific issue an extended upgrade program is actually being realized to accommodate SIS18 for the intermediate charge state booster operation.

• N. Pyka, U. Blell, C. Mühle, A. Saa Hernandez, P.J. Spiller, J. Stadlmann
  GSI, Darmstadt

The FAIR heavy ion synchrotrons SIS100/300 will provide heavy ion and proton beams with variable time structure. Fast extraction of compressed single bunches from SIS100, fast beam transfer between SIS100 and SIS300 and slow extraction from SIS100 and SIS300 will be provided. High average beam intensities and the generation of an uninterrupted linac-like beam are enabled by combining both heavy ion synchrotrons in different operation modes (fast acceleration and stretcher operation). In order to reduce beam loss at slow extraction of intense heavy ion beams and to minimize the beam load in subsequent accelerator structures, dedicated ion optical settings of the basic lattice functions and higher order corrections will be applied. However, the tight geometrical constraints in the rather short straight sections and the need to extract from both synchrotrons, fast and slow, at the same position and in parallel to the beam transport system, require operation parameters of the extraction devices close to the limits of technical feasibility. Higher order beam dynamics simulations and technical developments will be presented.