Intensity limitations of cooled heavy ion beams in the ESR

We consider the possibility of achieving maximum intensity and phase space density of heavy ions cooled by electrons in the Experimental Storage Ring to be built at GSI. Intrabeam scattering and the longitudinal microwave instability are found to be important limiting effects particularly at low energies. They are evaluated in diagrams, which can serve as a preliminary orientation for the expected performance of experiments. Examples have been calculated for U92+ at 50 and 500 MeV/u; in the latter case we find that <=109 ions at Δp/p=2x10-4 and epsilon=0.2π mm mrad are on the safe side for an assumed cooling time of 100 msec. We have also analyzed I20+ as a candidate for generating high energy density in matter. (orig.)