First isomeric quadrupole moment measured in fragmentation reactions: The case of 61 Fem 9/2+

N. Vermeulen , S. K. Chamoli , J. M. Daugas , M. Hass , D. L. Balabanski , J. P. Delaroche , Francois de Oliveira Santos (1) , G. Georgiev , M. Girod , G. Goldring , H. Goutte , S. Grévy (1) , I. Matea (2) , Pierre Morel , B. S. Nara Singh , Yu.-E. Penionzkevich , L. Perrot (1) , O. Perru , S. Péru , O. Roig , F. Sarazin , G.S. Simpson (3) , Yu. Sobolev , I. Stefan (1) , C. Stodel (1) , D. T. Yordanov , G. Neyens

1 GANIL - Grand Accélérateur National d'Ions Lourds
2 CENBG - Centre d'Etudes Nucléaires de Bordeaux Gradignan
3 ILL - Institut Laue-Langevin

This paper demonstrates the feasibility of quadrupole moment measurements on isomeric levels populated in projectile fragmentation reactions. The neutron-rich 61Fe(9/2+) [E*= 861 keV, T1/2= 239(5) ns] isomer was produced and spin aligned by the intermediate energy fragmentation of a 64Ni beam and implanted in a Cd single crystal. Its spectroscopic quadrupole moment |Qs|=41(6) e fm2 agrees with mean-field based calculations using the finite-range Gogny force, suggesting a moderately deformed shape characterized by an intrinsic charge quadrupole moment Q0=-85 e fm2 or Q0=+115 e fm2. The present measurement paves the way for future determinations of isomeric quadrupole moments in more exotic nuclei.

Domaines: Physique Nucléaire Expérimentale [nucl-ex]

N. Vermeulen, S. K. Chamoli, J. M. Daugas, M. Hass, D. L. Balabanski, et al.. First isomeric quadrupole moment measured in fragmentation reactions: The case of 61 Fem 9/2+. Physical Review C, 2007, 75, pp.051302. ⟨10.1103/PhysRevC.75.051302⟩. ⟨in2p3-00153274⟩