• T. Katayama, M. Steck
  GSI, Darmstadt
• T. Kikuchi
  Nagaoka University of Technology, Nagaoka, Niigata
• R. Maier, D. Prasuhn, R. Stassen, H. Stockhorst
  FZJ, Jülich
• I.N. Meshkov
  JINR, Dubna, Moscow Region

Anti-proton beam accumulation at CERN and FNAL has been performed with use of stochastic stacking in the momentum space. Thus accumulated beam has a large momentum spread and resultantly large radial beam size with large dispersion ring. In the present proposed scenario, beams from the pre-cooling ring are injected into the longitudinal empty space prepared by the barrier voltages and subsequently the stochastic cooling is applied. After the well cooling, barrier voltages will prepare again the empty space for the next beam injection. We have simulated the stacking process up to 100 stacking with use of the bunched beam tracking code including the stochastic cooling force and the diffusion force such as Schottky diffusion term, thermal diffusion, IBS effects. The synchrotron motion by barrier voltages are included with 4th order symplectic method. Examples of the application to 3 GeV anti-proton beam for the HESR ring in FAIR project are presented as well as the accumulation of heavy ion beam 3.5 GeV/u Au, at the NICA collider at JINR project.

• M. Steck, C. Brandau, C. Dimopoulou, C. Kozhuharov, F. Nolden
  GSI, Darmstadt

The ESR storage ring at GSI is operated with a wide range of heavy ions. In addition to stable heavy ions also rare isotope beams are studied in various experiments. A novel method to provide one- or few-component cooled fragment beams has been demonstrated experimentally. This technique uses a primary high energy heavy ion beam (several hundred MeV/u) bombarding a thick target in front of the storage ring. The reaction products are first separated by the magnetic structure of the storage ring. After storage of isotopes in a rigidity window of typically ± 2 per mille the isotopes are cooled to the same velocity by electron cooling. The cooled ions are circulating on different orbits according to their mass and charge. The momentum spread of the individual components is on the order 0.01 per mille or smaller depending on the intensity. The different components are radially well separated in regions with large dispersion. By the use of mechanical scrapers beam components in a certain radial region, corresponding to a range in masses and charges, can be selected, This way the stored rare isotope beam is curtailed to the components of choice.

• M. Steck, C. Dimopoulou, A. Dolinskyy, B. Franzke, T. Katayama, S.A. Litvinov, F. Nolden, C. Peschke
  GSI, Darmstadt
• D. Möhl, L. Thorndahl
  CERN, Geneva

In the complex of the accelerators of the FAIR project the RESR storage ring is mainly designed as an accumulator ring for antiprotons. The continuous accumulation of pre-cooled batches with a cycle time of 10 s from the collector ring is essential to achieve the goal of a production rate of 10 million antiprotons per second. The accumulation in the RESR uses a stochastic cooling system which operates in longitudinal phase space, similar as previous antiproton accumulator rings at CERN and FNAL. The ingredients of the accumulation system, the ring lattice functions, the electrode design and the electrical circuits have been studied in detailed simulations. A system has been found which safely provides the required performance and offers the option of upgrades, if higher accumulation rate is required in future. Maximum intensities of 100 billion cooled antiprotons are planned which are expected to stay below the instability threshold.