Experiments with highly-charged heavy-ions performed at the storage ring ESR

Abstract

The new heavy ion accelerator facility SIS/ESR was inaugurated in April 1990. During the 1991 the experimental storage ring, ESR, has been commissioned. Highly‐charged heavy ions from O8+ up to Bi82+ were successfully accumulated, cooled, and stored in the ring. Now all highly‐charged, heavy ions can be provided for experiments at comfortabl storage times and at energies roughly between 100 and 500 MeV/u. Λ report on the achievements and on the first experimental results will be given. For the experiments, special emphasis is put on capture processes in the electron cooler, i.e. on radiative and dielectronic recombination process as well as on capture events of bound target electrons from a gas jet. In this case, the capture leads either directly (REC) or by cascading to x‐ray emission, which is also exploited for a precision spectroscopy of the structure of the heaviest ions. Another exciting topic is the radioactive decay of highly charged ions: For instance the β‐decay into bound atomic states, which is not possible for neutral atoms, was studied for stored naked Dy ions.