The electron cooling device of the Heidelberg cooler storage ring has come into operation and for the first time has cooled ions heavier than protons. These experiments have proven that the cooling force is increasing with the charge of the ion. Cooling in the longitudinal and transverse phase space can increase the phase space density by up to four orders of magnitude. The usefulness of the method to increase the lifetime and the intensity of the stored particles was demonstrated resulting in a number of 3 × 1010 carbon particles which were successfully cooled and stored.

Combined multiturn injection scheme and radiofrequency stacking have been employed, at the Heidelberg test storage ring, to fill both the horizontal transverse and the longitudinal phase spaces: an intensity enhancement factor of approximately 800 was thus obtained in the stored beam with respect to the injected one.

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

The Heavy Ion Test Storage Ring TSR [1] is an experimental facility for accelerator, atomic and nuclear physics studies presently under construction at the Heidelberg Max-Planck-Institute. The storage ring is designed for heavy ions of up ∼ 30 MeV/u at a charge to mass ratio of qA = 0.5, corresponding to a magnetic rigidity of Bρ = 1.5 Tm.

A superconducting quarter-wave-resonator at 325 MHz has been designed that could be used as a debuncher for the Heidelberg postaccelerator. The design study utilized the computer codes SUPERFISH and URMEL as well as a theory considering the quarter-wave-resonator as a piece of transmission line shorted at one end. These calculations were used to optimize H p /ε acc , E p /ε acc and U/ε 2 acc . According to measurements with a model resonator the copper body of a first prototype resonator has been machined. In first experiments with an electrochemically plated lead surface an unloaded quality Q 0 = 6 × 10 7 has been measured. The highest accelerating field obtained in that test amounted to ε acc = 1.8 MV/m at Q 0 = 1.0 × 10 7 .