1. 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

2. 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

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

4. 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 Sn
108Sn B(E2) = 0.230(57) e2b2
A. Banu et al., PRC (R) (2005)
For Sn: Data available from
MSU, Vaman et al.

5. 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?

6. 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

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

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

9. 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

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

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

12. 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