Hinterberger, F. (Corresponding author)FZJ*

2006
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag Jülich

Report No.: Juel-4206

Abstract: The beam-target interaction is studied with respect to the transverse and longitudinal emittance growth of the HESR antiproton beam. The transverse emittance growth caused by the small angle Coulomb scattering can be described analytically using the differential cross section of the Coulomb interaction. Similarly, the longitudinal emittance growth caused by the energy loss of the beam can be calculated using the differential cross section of the energy-loss distribution. It is shown that particles with energy losses near the maximum energy loss in a head-on collision with a target electron are lost due to momentum acceptance of the HESR ring. Taking a relative momentum acceptance of about $1 \cdot 10^{-3}$ into account yields an order of magnitude smaller growth rate of the mean square momentum deviation. The necessary cooling rates for the High Resolution mode and the High Luminosity mode are deduced assuming that the beam-target interaction is the dominant beam heating process. For comparison the effects of intrabeam scattering are estimated. For electron and stochastic cooling, analytic expressions are quoted in order to evaluate the momentum resolution and cooling rate. The potentialities of electron and stochastic cooling are discussed with respect to the achievable momentum resolution and beamtarget overlap. Beam loss rates and average luminosities are evaluated taking the total hadronic cross section, the restricted momentum acceptance of the HESR ring, the large angle Coulomb scattering and the Touschek effect into account.

Keyword(s): beam ; target ; interaction ; Coulomb excitation

1. Experimentelle Hadrondynamik (IKP-2)
2. Experimentelle Hadronstruktur (IKP-1)
3. Kernphysikalische Großgeräte (IKP-4)
4. Institut 3 (Theoretische Kernphysik) (IKP-3)