Coulomb Excitation of 114, 116Sn P. Doornenbal1,2, P. Reiter1, P. Bednarczyk2, L. Caceres2, J. Cederkäll3,4, A. Ekström3, J. Gerl2, M. Górska2, A. Jinghan5, R. Kumar5, R.P. Singh5, H.-J. Wollersheim2 1Institute for Nuclear Physics, University of Cologne, Germany 2Gesellschaft für Schwerionenforschung, Darmstadt, Germany 3PH Department, CERN, Geneva, Switzerland 4Physics Department, University of Lund, Sweden 5Inter University Accelerator Centre, New Delhi, India

Outline Motivation The Experiment Results Conclusions and Outlook Seniority scheme Experimental B(E2) values of Sn isotopes Comparison with LSSM calculations The Experiment Sub-barrier Coulomb excitation of 114, 116Sn Results How does the value for 114Sn fit in the picture? Conclusions and Outlook

Seniority Scheme B(E2) ~ Nparticles* Nholes Experimental 2+ and 4+ Levels of Sn isotopes How about the B(E2)? B(E2) ~ Nparticles* Nholes

Experimental B(E2) values of Sn Isotopes 2 Methods applicable for neutron deficient Sn isotopes: Sub-barrier Coulex Relativistic Energy Coulex 110Sn B(E2) = 0.220(22) e2b2 J. Cerderkäll et al., submitted to PRL Stable Sn isotopes from 112-124Sn 108Sn B(E2) = 0.230(57) e2b2 A. Banu et al., PRC 061305(R) (2005) For 106-112Sn: Data available from MSU, Vaman et al.

Comparison with Shell Model Calculations 100Sn core, M. Hjorth-Jensen et al.: ν(d5/2g7/2s1/2h11/2), eν = 1.0e 90Zr core, F. Nowacki et al.: ν(d5/2g7/2s1/2h11/2), eν = 0.5e, π(g9/2g7/2d5/2d3/2s1/2), eπ = 1.5e πν monopoles tuned to ESPEs and Z = 50 shell gap Does 114Sn follow the trend of high B(E2) values?

Coulex Experiment Previous Coulex measurements were performed using 114Sn as target material Natural abundance is only 0.65% Enriched materials have contaminations of other Sn isotopes, which cannot be separated, as the 2+ levels have the same energy 114Sn used as beam and studied via inverse kinematics 116Sn measured in addition to minimize systematic errors Sub-barrier beam energies of 3.4 A MeV provided by the UNILAC at GSI

Experimental Setup Scattered particle identification with PPAC 114,116Sn 0.7 mg/cm2 58Ni Target 2 Super-Clover HPGE Detectors

Particle Identification Particle identification with PPAC 2 Particles + γ required 114Sn Scattering Angle 58Ni Time (PPACL-PPACR) Doppler Correction for 58Ni and 114,116Sn

Coulomb Excited Level Schemes Probability to excite all other states relative to the first 2+ in 114, 116Sn ≈ 2% For 58Ni the probability to excite all other states relative to the first 2+ is < 0.3% 114Sn 116Sn

B(E2) Value Determination Contributions from higher lying states taken into account Literature value for 116Sn = 0.209(6) e2b2 Literature value for 58Ni = 0.0493(7) e2b2 Two possibilities to determine B(E2) of 114Sn: Relative to 58Ni: Relative to 116Sn:

B(E2) Systematics for Sn isotopes 114Sn B(E2) = 0.231(7) e2b2

Conclusion and Outlook B(E2) of 114Sn determined to 0.231(7) e2b2 This value is higher than expected from state of the art LSSM calculations using a 110Sn or 90Zr core Supports the observed high B(E2) values for 108,110Sn Next step: A precise measurement of the B(E2) of 112Sn