Nov 25 – 27, 2013
Europe/Zurich timezone

Coulomb excitation of 140Sm

Nov 27, 2013, 3:20 PM
The Globe (CERN)

The Globe



Malin Linnea Klintefjord (University of Oslo (NO))


The open-shell nuclei with Z>50 and N<82 are known to have some of the largest ground- state deformations in the nuclear chart. The shape of the nuclei in this region are expected to be prolate, except for a small island of nuclei with Z>62 and N≈78, which are predicted to be oblate. Nuclei near 140Sm are therefore expected to be located in a transitional region between deformed and spherical shapes (as a function of neutron number) and between prolate and oblate shapes (as a function of proton number), and shape coexistence may be expected to occur. Indeed, a low-lying excited 0+ state was tentatively assigned in 140Sm, which could be interpreted as a sign for shape coexistence. The measurement of spectroscopic quadrupole moments and transition strengths represents a sensitive test for theoretical predictions in this region. Due to the occurrence of two isomeric 10+ states of \pi(h_{11/2})^2 $ and $\nu(h_{11/2})^{-2} $ configuration the lifetimes of low-lying states are completely unknown. A Coulomb excitation experiment with a 140Sm beam on a 94Mo target was performed at ISOLDE with the typical setup comprising Miniball and a DSSD in June/July 2012. The laser- ionized beam of 140Sm was quasi-pure with an average intensity of 2*10^5 particles per second. At least three excited states in 140Sm were populated during the experiment: the 2+ and 4+ states of the ground-state band and the tentatively assigned 0+ state at 990 keV excitation energy. The statistics collected during the experiment allows the analysis of differential Coulomb excitation cross sections as a function of scattering angle. Experimental details and first preliminary results obtained in the analysis with GOSIA2 will be discussed.

Primary author

Malin Linnea Klintefjord (University of Oslo (NO))


Andreas Görgen (University of Oslo) Ann-Cecilie Larsen (EPF group-Department of Physics-University of Oslo) Francesca Giacoppo (University of Oslo (NO)) Gry Tveten (University of Oslo (NO)) Dr Magdalena Zielinska (CEA Saclay) Dr Sunniva Siem (University of Oslo)

Presentation materials