Messung von durch die Hyperfein-Wechselwirkung beeinflussten Zerfällen schwerer Ionen in Schwerionenspeicherring und Elektronenstrahl-Ionenfalle (EBIT)
Final Report Abstract
The hyperfine interaction in the atom, between the nuclear spin and the electrons of the outer shell, provides a probe of the nuclear magnetic moment distribution in the nucleus and thus helps to find out details of nuclear magnetic field generation. The same hyperfine interaction perturbs the electronic shells, changes symmetries, and enables transitions that otherwise are strictly forbidden. Spectroscopic precision measurements in the n=2 shell of few-electron ions of very heavy elements (Pr, Bi) have been performed at the SuperEBIT electron beam ion trap at Livermore (CA, USA), resulting in accurate determinations of hyperfine splittings of even and odd parity n=2 levels in Li- and Be-like ions. Complementary work measured the atomic lifetimes of levels in highly charged ions that decay only because of hyperfine interaction, or which have lifetimes that are markedly affected by hyperfine interaction. At Livermore, such measurements on Ni-like ions were the first to demonstrate E2/M3 decay channel mixing. At the Heidelberg heavy-ion storage ring TSR, lifetime measurements on Mg-like ions used ultraviolet-optical (UV) and newly developed extreme-ultraviolet optical (EUV) detection systems. The UV technique turned out to be sensitive enough to test the hyperfine effect with considerable precision and also to determine isotopic differences.
Publications
- Time-resolved soft-x-ray spectroscopy of a magnetic octupole transition in nickel-like xenon, cesium, and barium ions. Phys. Rev. A 73, 022508 (2006) (8 pp)
E. Träbert, P. Beiersdorfer, G. V. Brown, K. R. Boyce, R. L. Kelley, C. A. Kilboume. F. S. Porter, A. Szymkowiak
- Observation of hyperfine mixing in measurements of a magnetic octupole decay in isotopically pure nickel-like 129xe and 132xe ions. Phys. Rev. Lett. 98, 263001 (2007)
E. Träbert. P. Beiersdorfer. G. V. Brown
