The Heidelberg heavy ion cooler storage ring TSR

Commissioning of the Heidelberg Test Storage Ring (TSR) started in May 1988. The TSR is a low-energy cooler storage ring for heavy ions with energies up to 30 MeV/amu at a charge-to-mass ratio 1/A=0.5. Phase space cooling for coasting beams as well as for bunched beams is routinely done by electron cooling. As the ring is fed by a tandem linac combination, stored intensities of up to 1×10¹⁰ particles are obtained by combined stacking into transversal and longitudinal phase space (multiturn injection and RF stacking). This stacking method gives 800 times the number of stored ions compared to single-turn injection. Cooling oxygen and carbon beams resulted in a typical emittance of 0.3 π mm-mrad and a momentum spread of Δp/p=10^-4. The equilibrium was mainly determined by intrabeam scattering, and the heating in the residual gas was mainly determined by multiple scattering. An overall increase of phase space density by six orders of magnitude was observed, similar to cooling results at proton machines. Results on the first year of operation with heavy ions at the TSR are reported