The exploration of the unique properties of stored and cooled beams of highly-charged ions as provided by heavy-ion storage rings has opened novel and fascinating research opportunities in the realm of atomic and nuclear physics research. Since the late 1980s, pioneering work has been performed at the CRYRING at Stockholm (Abrahamsson et al. 1993) and at the Test Storage Ring (TSR) at Heidelberg (Baumann et al. 1988). For the heaviest ions in the highest charge-states, a real quantum jump was achieved in the early 1990s by the commissioning of the Experimental Storage Ring (ESR) at GSI Helmholtzzentrum fur Schwerionenforschung (GSI) in Darmstadt (Franzke 1987) where challenging experiments on the electron dynamics in the strong field regime as well as nuclear physics studies on exotic nuclei and at the borderline to atomic physics were performed. Meanwhile also at Lanzhou a heavy-ion storage ring has been taken in operation, exploiting the unique research opportunities in particular for medium-heavy ions and exotic nuclei (Xia et al. 2002).

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Physics book: CRYRING@ESR

Electric-dipole intercombination and forbidden transitions have been optically observed with ions circulating in a storage ring, and atomic lifetimes determined. For the level in the Be-like ion , the measured lifetime of ms corresponds to a transition probability of . This result ties in with experimental work on the neighbouring ion and with recent calculations. For the corresponding level in the Mg-like ion , a lifetime of s (transition rate ) has been measured, corroborating earlier experiments but not the more recent calculations. The transition probability of the M1/E2 transition between the fine-structure levels of the ground state in F-like has been determined as , in agreement with the results of semi-empirically corrected multi-configuration Dirac-Fock calculations.

Measurement of the B+ and Al+ intercombination and Sc12+ forbidden transition rates at a heavy-ion storage ring

For many years, atomic lifetime measurements on multiply-charged ions have been done almost exclusively by beam-foil spectroscopy. For low ion charges, however, spin-changing "intercombination" transitions have a rate that renders them too slow for traditional fast-beam techniques. Here ion traps and fast-ion beams have been combined in the concept of heavy-ion storage rings. These devices have permitted not only an extension of intercombination lifetime measurements down to singly charged ions, but they also facilitated similar measurements on electric-dipole forbidden transitions. The electron-beam ion trap (EBIT) complements the storage-ring work for work on highly charged ions. Achievements, technical issues, and prospects are outlined. PACS Nos.: 32.70Cs, 32.30Jc, 34.50Fa

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Precise atomic lifetime measurements with stored ion beams and ion traps

Relativistic many-body calculations of electric-dipole lifetimes, transition rates, and oscillator strengths for n=3 states in Al-like ions

Systematic variation of the electron-beam energy in an electron-beam ion trap has been employed to produce soft-X-ray spectra (20 to 60 A) of Au with well-defined maximum charge states ranging from...

Soft-X-ray spectra of highly charged Au ions in an electron-beam ion trap

N=3, Δn=0 transitions in Na-like ions have been observed and the resonance level lifetimes have been measured by time-resolved spectroscopy of foil-excited ion beams of Xe (Z=54) and Au (Z=79). Other lines in the same wavelength range are identified withn=3, Δn=0 transitions in Ne-, Mg-, and Al-like ions. Wavelengths and transition rates for these new lines are compared to the available theoretical data. A number of experimental problems are discussed.

P. Rymuza

Papers

Time resolved EUV spectroscopy on foil-excited 5.9 MeV/u Xe and 13.2 MeV/u Au ions

Experimental n=3 level lifetimes of Na-like heavy ions in the realm of massive relativistic effects