Measurement of atomic spectra and level lifetimes in multiply charged ions of astrophysical interest
Final Report Abstract
Aiming at quality assurance of precise level lifetime measurements of low-lying levels in ions of astrophysical interest, systematic measurements have been undertaken at a heavy-ion storage ring, and large scale calculations of proven accuracy have been instigated for ions of several isoelectronic sequences. The measurements on one hand demonstrate the reliability (much better than 1% accuracy) of the storage ring technique for ions with an n=2 valence shell, but they also reveal the presence of systematic error sources that can hamper the determination of lifetimes of n=3 valence shell ions, in particular the population of specific long-lived 3d levels in the injector accelerator foil stripper. This particular systematic error must be different in other ion sources such as electron cyclotron resonance ion sources and electron beam ion traps and is likely due to the electron density at ion production. This error has to be brought under control in order to realize the actual potential of such lifetime measurements for testing details of QED beyond the Standard Model. Our new data and our isoelectronic analysis of the results of a string of such projects illustrate another obstacle on the path to high-physics yield comparisons with theory, that is, significant shortcomings in the non-QED part of atomic structure calculations of many-electron systems.
Publications
- In pursuit of high precision atomic lifetime measurements of multiply charged ions. J. Phys. B: At. Mol. Opt. Phys. 43, 074034 (2010) (19 pp)
E. Träbert
- Heavy-ion storage ring lifetime measurement of metastable levels in the C-, N-, and O-like ions of Si, P, and S. Phys. Rev. A 85, 052508 (2012) (8 pp)
E. Träbert, M. Grieser, J. Hoffmann, C. Krantz, R. Repnow, A. Wolf
(See online at https://doi.org/10.1103/PhysRevA.85.042508) - Isoelectronic trends of the E1-forbidden decay rates of Al-, Si-, P-, and S-like ions of Cl, Ti, Mn, Cu, and Ge. J. Phys. B 45, 215003 (2012) (19 pp)
E. Träbert, M. Grieser, C. Krantz, R. Repnow, A. Wolf, F. J. Diaz, Y. Ishikawa, J. A. Santana
(See online at https://doi.org/10.1088/0953-4075/45/21/215003) - Level lifetimes dominated by electric-dipole forbidden decay rates in the ground configuration of doubly charged rare gas ions (Ne2+, Ar2+, Kr2+, Xe2+). Comm. At. Mol. Opt. Phys. / Physica Scripta 85, 048101 (2012) (6 pp)
E. Träbert
- M1 and E2 decay dependent lifetime of the lowest 1S0 level in C-like ions up to Ne4+ measured at a heavy-ion storage ring. New J. Phys. 14, 023061 (2012) (11 pp)
E. Träbert, M. Grieser, R. v. Hahn, C. Krantz, R. Repnow, A. Wolf
(See online at https://doi.org/10.1088/1367-2630/14/2/023061)
