Recent Results on Equilibrium Temperatures and Cooling Forces with Electron Cooled Heavy Ion Beams in the ESR

Electron cooling of heavy ions over the whole rna~s range has been performed in the storage ring ESR. Measure-ments of the longitudinal cooling force for a variety of ions have revealed a significant deviation from the Q2-dependence for small relative velocity. Measurements of the equilibrium beam properties of cooled heavy ions ev-idenced that the achievable phase space density is deter-mined by a balance between cooling and heating by intra-beam scattering. Calculations of the corresponding intra-beam scattering rates for a ug2+ beam are compared with the cooling rates of the electron beam concluded from the cooling force measurements.