8th International Topical SPARC Workshop
and SPARC Lecture Days
Moscow, September 5-10, 2011 -
Information

Title:	Prof.
Family Name:	Schippers
First Name:	Stefan
Gender:	male
E-Mail:	Stefan.Schippersiamp.physik.uni-giessen.de
Affiliation for Badge:	Universität Gießen
Institute:	Institut für Atom- und Molekülphysik
Address (Street):	Leihgesterner Weg 217
Postal Code, City:	35392 Gießen
Country:	Germany
Phone:	06419915203
Fax:	06419915109
Arrival Date:	September 4
Departure Date:	September 11
Type of Participation:	Regular
Are you a member of the SPARC collaboration ?:	Yes
I register for:	Topical SPARC Workshop
	Selected
Contribution Type:	Oral
Author(s):	S. Schippers1, D. Bernhardt1, M. Grieser2, M. Hahn3, C. Krantz2, M. Lestinsky4, A. Müller1, O. Novotný3, R. Repnow2, D. W. Savin3 and A. Wolf2
Institute(s):	1 Institut für Atom-und Molekülphysik, Justus-Liebig-Universität Giessen, 35392 Giessen, Germany 2 Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany 3 Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027, USA 4 Helmholtzzentrum für Schwerionenforschung mbH, 64291 Darmstadt, Germany
Title:	Hyperfine-induced and two-photon transitions in beryllium-like ions
Abstract:	Extremely long lived atomic states such as the lowest excited state in beryllium-like ions, i.e, the 2s2p 3P0 state which cannot decay via a one-photon transition, are highly sensitive to correlations within the atomic shell and even to the nuclear structure of the ions. In particular, the hyperfine interaction can quench the 2s2p 3P0 state if the nucleus has nonzero magnetic moment. Theoretical calculations [1-5] of hyperfine induced (HFI) transition rates in beryllium-like ions disagree significantly with the only experimental result published to date [6] which was obtained from a storage-ring experiment with 47Ti18+ ions. In order to broaden the experimental data base, HFI lifetime measurements with other beryllium-like ions are being performed at the Heidelberg heavy-ion storage ring TSR. Most recently, we have performed storage-ring measurements with isotopically enriched 33S12+ ions. First results will be presented and compared with recent theoretical calculations which predict a value of ~10.7 s [2,3] for the HFI lifetime of the 2s2p 3P0 state in beryllium-like 33S12+. Perspectives for measurements of the E1M1 two photon transition rates will be discussed as well. [1] J. P. Marques et al., Phys. Rev. A 47, 929 (1993). [2] K. T. Cheng et al., Phys. Rev. A 77, 052504 (2008). [3] M. Andersson et al., Phys. Rev. A 79, 032501 (2009). [4] J. Li and C. Dong, Plas. Sci. Technol. 12, 364 (2010). [5] J. Li et al., Phys. Lett. A 375, 914-917 (2011). [6] S. Schippers et al., Phys. Rev. Lett. 98, 033001 (2007).

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