Half-life measurements of bare, mass-resolved isomers in a storage-cooler ring

摘要

Secondary beams from fragmentation of (sup 58)Ni have been produced with energies of 200-220 A.MeV, separated with the fragment separator FRS and injected into the storage-cooler ring ESR for half-life measurements. The relative momentum spread (Delta)p/p(approx)1.10(sup -6) (FWHM) which we achieved allowed us to resolve the ground and isomeric states of cooled (sup 52)Mn and (sup 53)Fe nuclei in the measured mass spectra. The circulating beams were fully ionized which rendered possible, for the first time, to measure pure (beta)(sup +) branches for (sup 52g)Fe and (sup 53g)Fe and the sum of pure (beta)(sup +) and (gamma) branches in the decay of the isomers (sup 52m)Mn and (sup 53m)Fe. (orig.)