Feb 12 – 14, 2007
CERN
Europe/Zurich timezone

Coulomb excitation of neutron-rich 44Ar at SPIRAL

Feb 13, 2007, 11:30 AM
20m
Council Chamber, 503/1-001 (CERN)

Council Chamber, 503/1-001

CERN

Speaker

Magda Zielinska (CEA Saclay)

Description

A low-energy Coulomb excitation experiment on neutron-rich 44Ar has been performed at the SPIRAL facility of GANIL. The primary question addressed by the experiment was the possible weakening of the N=28 shell closure in neutron-rich nuclei and, closely connected to that, the development of deformation and shape coexistence in this region of the nuclear chart. A beam of 44Ar was produced by fragmentation of a primary 48Ca beam at 60 A MeV on the carbon production target of SPIRAL. The Ar44 fragments were re-accelerated in the CIME cyclotron to 2.7 and 3.7 MeV/nucleon and Coulomb excited on 109Ag and 208Pb targets, respectively. The scattered projectiles and recoiling target nuclei were detected in a highly segmented double-sided silicon detector and the gamma rays were detected with the EXOGAM germanium detector array. Apart from the first excited 2+ state, at least one higher-lying level was populated. The level of statistics is sufficient to determine the gamma-ray yields for several ranges of scattering angles and for the two different target materials. Although the analysis is still in progress, it is anticipated that the collected data will allow extracting the transition probabilities between the observed states, as well as the static quadrupole moment of the first 2+ state. It is anticipated to continue in this experimental program with the Coulomb excitation of 46Ar.

Primary author

Magda Zielinska (CEA Saclay)

Co-authors

Alexander Buerger (University of Bonn) Andreas Goergen (CEA Saclay) Cedric Dossat (CEA Saclay) Christophe Theisen (CEA Saclay) Daniel Pietak (Warsaw University of Technology) Emmanuel Clement (CERN) Geirr Sletten (NBI Copenhagen) Jedrzej Iwanicki (HIL Warsaw) Joa Ljungvall (CEA Saclay) Julian Srebrny (HIL Warsaw) Katarzyna Wrzosek (HIL Warsaw) Pawel J. Napiorkowski (HIL Warsaw) Wilton Catford (University of Surrey) Wolfram Korten (CEA Saclay)

Presentation materials