IPAC2011 - List of Keywords (accumulation)

Paper	Title	Other Keywords	Page
MOPS046	Impedances and Wakes in Round Three-layer Ceramic Waveguide	impedance, acceleration, radiation, damping	703
	M. Ivanyan, A.V. Tsakanian CANDLE, Yerevan, Armenia
	The round ceramic waveguide with inner and outer thin metal coating is considered. Using the exact methods the longitudinal impedances and potentials are calculated. Identification of the main patterns of changes in their properties by varying the electrodynamic and geometric parameters of the waveguide is performed as well. The possibility of optimizing the parameters of the waveguide for the effective implementation of two-beam acceleration is discussed.

MOPS053	Electron Cloud Effects in Coasting Heavy-ion Beams*	electron, simulation, ion, dipole	724
	F.B. Petrov, T. Weiland TEMF, TU Darmstadt, Darmstadt, Germany O. Boine-Frankenheim GSI, Darmstadt, Germany
	Funding: Work supported by BMBF under contract 06DA9022I. During slow extraction of intense ion beams electron clouds (EC) can accumulate in the circulating coasting beam and reduce the extraction efficiency. This is a concern for the existing SIS-18 heavy ion synchrotron at GSI and for the projected SIS-100 as part of the FAIR project. For medium energy heavy-ion beams the production of electrons from residual gas ionization is very effective. The electron density is limited due to Coulomb scattering by the beam ions. Above a threshold beam intensity the two-stream instability and the resulting coherent beam oscillations limit the electron density. Below this threshold the electron cloud can lead to observable deformations of the Schottky side-bands. To avoid EC build-up one can introduce a gap in the beam using barrier rf bucket. The reduction of the build-up efficiency caused by the gap is studied in details based on the solution of the Hill's equation for electrons. Finally we estimate the saturation level for the electron cloud density.

THPS003	Status of Stochastic Cooling Predictions at the HESR	antiproton, pick-up, kicker, injection	3430
	H. Stockhorst, R. Maier, D. Prasuhn, R. Stassen FZJ, Jülich, Germany T. Katayama GSI, Darmstadt, Germany
	Detailed theoretical studies of stochastic cooling have been performed in order to fulfil the requirements for internal target experiments at the High-Energy Storage Ring (HESR) of the future Facility for Antiproton and Ion Research (FAIR) at the GSI in Darmstadt. A Fokker-Planck model and a particle tracking code utilizing the Filter and time-of-flight momentum cooling method have been developed for the 2 to 4 GHz cooling system. A barrier bucket cavity is included to compensate the mean energy loss due to the beam-target interaction. The code has been experimentally verified at the cooler synchrotron COSY. Since the RESR accumulator ring is postponed in the modularized start version of FAIR it is proposed to include the anti-proton accumulation function in the HESR downstream of the Collector Ring. Applying the radial stacking scheme well established at CERN and FNAL would result in a completely new and additional cooling system in the HESR. Instead a different way of beam accumulation has been selected that uses the already designed stochastic cooling system and the barrier bucket cavity of the HESR. Simulation results of the anti-proton accumulation in the HESR are presented.

Paper

Title

Other Keywords

Page

MOPS046

Impedances and Wakes in Round Three-layer Ceramic Waveguide

impedance, acceleration, radiation, damping

703

M. Ivanyan, A.V. Tsakanian
CANDLE, Yerevan, Armenia

The round ceramic waveguide with inner and outer thin metal coating is considered. Using the exact methods the longitudinal impedances and potentials are calculated. Identification of the main patterns of changes in their properties by varying the electrodynamic and geometric parameters of the waveguide is performed as well. The possibility of optimizing the parameters of the waveguide for the effective implementation of two-beam acceleration is discussed.

MOPS053

Electron Cloud Effects in Coasting Heavy-ion Beams*

electron, simulation, ion, dipole

724

F.B. Petrov, T. Weiland
TEMF, TU Darmstadt, Darmstadt, Germany
O. Boine-Frankenheim
GSI, Darmstadt, Germany

Funding: Work supported by BMBF under contract 06DA9022I.
During slow extraction of intense ion beams electron clouds (EC) can accumulate in the circulating coasting beam and reduce the extraction efficiency. This is a concern for the existing SIS-18 heavy ion synchrotron at GSI and for the projected SIS-100 as part of the FAIR project. For medium energy heavy-ion beams the production of electrons from residual gas ionization is very effective. The electron density is limited due to Coulomb scattering by the beam ions. Above a threshold beam intensity the two-stream instability and the resulting coherent beam oscillations limit the electron density. Below this threshold the electron cloud can lead to observable deformations of the Schottky side-bands. To avoid EC build-up one can introduce a gap in the beam using barrier rf bucket. The reduction of the build-up efficiency caused by the gap is studied in details based on the solution of the Hill's equation for electrons. Finally we estimate the saturation level for the electron cloud density.

THPS003

Status of Stochastic Cooling Predictions at the HESR

antiproton, pick-up, kicker, injection

3430

H. Stockhorst, R. Maier, D. Prasuhn, R. Stassen
FZJ, Jülich, Germany
T. Katayama
GSI, Darmstadt, Germany

Detailed theoretical studies of stochastic cooling have been performed in order to fulfil the requirements for internal target experiments at the High-Energy Storage Ring (HESR) of the future Facility for Antiproton and Ion Research (FAIR) at the GSI in Darmstadt. A Fokker-Planck model and a particle tracking code utilizing the Filter and time-of-flight momentum cooling method have been developed for the 2 to 4 GHz cooling system. A barrier bucket cavity is included to compensate the mean energy loss due to the beam-target interaction. The code has been experimentally verified at the cooler synchrotron COSY. Since the RESR accumulator ring is postponed in the modularized start version of FAIR it is proposed to include the anti-proton accumulation function in the HESR downstream of the Collector Ring. Applying the radial stacking scheme well established at CERN and FNAL would result in a completely new and additional cooling system in the HESR. Instead a different way of beam accumulation has been selected that uses the already designed stochastic cooling system and the barrier bucket cavity of the HESR. Simulation results of the anti-proton accumulation in the HESR are presented.