Secondary beams of radioactive heavy ions have been stored and cooled in a storage ring for the first time. Relativistic beams of bare ${}_{}{}^{19}{}_{}{}^{}\mathrm{Ne}$ and ${}_{}{}^{18}{}_{}{}^{}\mathrm{F}$ ions were produced by fragmentation of 310 MeV/nucleon ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ at the heavy-ion synchrotron at GSI. They were separated in flight with the high-resolution forward spectrometer and injected into the storage-cooler ring. The feasibilities of in-flight lifetime and direct mass measurements for radioactive beams are demonstrated.

• Received 23 March 1992

DOI:https://doi.org/10.1103/PhysRevLett.68.3412