Author: Maier, R.
Paper Title Page
MOPEA016 The Main Stochastic Cooling System of the HESR 100
  • R. Stassen, R. Greven, R. Maier, G. Schug, H. Stockhorst
    FZJ, Jülich, Germany
  The main stochastic cooling system of the High-Energy Storage Ring HESR (1.5-15 GeV/c) for antiprotons at the FAIR complex (Facility for Antiprotons and Ion Research) in Darmstadt (GSI) will work in the frequency range of 2 - 4 GHz. The design work on pickup and kicker is now finished and the production of the first cooling tank has been started. The whole system layout will be presented taking into account new additional requirements concerning the accumulation and the cooling of heavy ions. All beam-coupling structures are nearly identical and contain several ring-slot blocks. These blocks consist of eight wall-current monitors coupled out by eight electrodes each. Most of the signal combining and splitting take place within the vacuum envelope to reduce the number of vacuum RF feed throughs. The long-distance transmission of the signals and the filters containing long signal delays work with near infrared optical elements.  
MOPEA017 Electron Cooling of Heavy Ions Interacting with Internal Target at HESR of FAIR 103
  • T. Katayama, M. Steck
    GSI, Darmstadt, Germany
  • R. Maier, D. Prasuhn, H. Stockhorst
    FZJ, Jülich, Germany
  The High Energy Storage Ring (HESR) is designed and optimized to accumulate and store the anti-proton beam for the internal target experiment. The recent demand of atomic physics has impacted to use the HESR facility also as the storage ring of bare heavy ions. In this concept the bare heavy ions are injected at 740 MeV/u from the Collector Ring where the ions are well stochastically cooled to be matched with HESR ring acceptance. In the HESR the 2 MeV electron cooler is prepared with the maximal electron current of 3 A and the cooling length of 2.7 m. The electron cooling process of typically 238U92+ beam is simulated for the Hydogen and Xe internal target with simultaneous use of barrier voltage to compensate the mean energy loss caused by the interaction with internal target. In the present report the detailed simulation results of 6D phase space obtained by the particle tracking code are precisely discussed.  
MOPEA018 Feasibility Study of Heavy Ion Storage and Acceleration in the HESR with Stochastic Cooling and Internal Targets 106
  • H. Stockhorst, R. Maier, D. Prasuhn, R. Stassen
    FZJ, Jülich, Germany
  • T. Katayama
    GSI, Darmstadt, Germany
  Stochastic cooling of heavy ions is investigated under the constraint of the present hardware design of the cooling system and RF cavities as well as the given magnet design as foreseen for anti-proton cooling in the HESR of the FAIR facility. A bare uranium beam is injected from the collector ring CR into the HESR at 740 MeV/u. The beam preparation for an internal target experiment with cooling is outlined. The acceleration of the ion beam to 2 GeV/u is studied under the basic condition of the available cavity voltages and the maximum magnetic field ramp rate in the HESR. The cooling simulations include the beam-target interaction due to a Hydrogen and Xenon target. Diffusion due to Schottky and thermal noise as well as intra beam scattering is accounted for. Due to the higher charge states of the ions Schottky particle noise power becomes an important issue. The analysis considers the electronic power limitation to 500 W in case of momentum cooling. Fast Filter cooling is only available if the revolution harmonics do not overlap in the cooling bandwidth. Since overlap occurs for lower energies the application of the Time-Of-Flight (TOF) momentum cooling method is discussed.  
WEPEA036 Spin Tune Decoherence Effects in Electro- and Magnetostatic Structures 2579
  • Y. Senichev, R. Maier, D. Zyuzin
    FZJ, Jülich, Germany
  • N.V. Kulabukhova
    St. Petersburg State University, St. Petersburg, Russia
  In Electric Dipole Moment search experiments with polarized beams the coherence of spin oscillations of particles has a crucial role. The decoherent effects arise due to spin tune dependence on particle energy and particle trajectory in focusing-deflecting fields. They are described through the n-th order spin tune aberrations. Since the first order is suppressed by RF field, the second order plays crucial role. It depends on the orbit lengthening and on the odd order field components. We consider the spin decoherence effects and methods of their compensation in different channels, electrostatic, magnetostatic linking the decoherence effects with common characteristics such as the momentum compaction factor, the chromaticity and others.  
WEPEA037 Testing of Symplectic Integrator of Spin-orbit Motion Based on Matrix Formalism 2582
  • A.N. Ivanov, S.N. Andrianov, N.V. Kulabukhova
    St. Petersburg State University, St. Petersburg, Russia
  • R. Maier, Y. Senichev, D. Zyuzin
    FZJ, Jülich, Germany
  Investigation of spin-orbital motion in electromagnetic fields requires different numerical methods. Approaches for long-term evolution modelling need both performance and symplecticity. In this paper we discuss matrix maps method for numerical simulation. We examine symplectification and accuracy in terms of electostatic storage ring. The results are compared with traditional symplectic step-by-step methods.