Measurement of the sign of the spectroscopic quadrupole moment for the 2(1)(+) state in Se-70: No evidence for oblate shape

Summary, in English

Using a method whereby molecular and atomic ions are independently selected, an isobarically pure beam of Se-70 ions was postaccelerated to an energy of 206 MeV using REX-ISOLDE. Coulomb-excitation yields for states in the beam and target nuclei were deduced by recording deexcitation gamma rays in the highly segmented MINIBALL gamma-ray spectrometer in coincidence with scattered particles in a silicon detector. At these energies, the Coulomb-excitation yield for the first 2(+) state is expected to be strongly sensitive to the sign of the spectroscopic quadrupole moment through the nuclear reorientation effect. Experimental evidence is presented here for a prolate shape for the first 2(+) state in Se-70, reopening the question over whether there are, as reported earlier, deformed oblate shapes near to the ground state in the light selenium isotopes.

• Author: A. M. Hurst; P. A. Butler; D. G. Jenkins; P. Delahaye; F. Wenander; F. Ames; C. J. Barton; T. Behrens; A. Burger; Joakim Cederkäll; E. Clement; T. Czosnyka; T. Davinson; G. de Angelis; J. Eberth; Andreas Ekström; S. Franchoo; G. Georgiev; A. Gorgen; R. -D. Herzberg; M. Huyse; O. Ivanov; J. Iwanicki; G. D. Jones; P. Kent; U. Koester; T. Kroell; R. Kruecken; A. C. Larsen; M. Nespolo; M. Pantea; E. S. Paul; M. Petri; H. Scheit; T. Sieber; S. Siem; J. F. Smith; A. Steer; I. Stefanescu; N. U. H. Syed; J. Van de Walle; P. Van Duppen; R. Wadsworth; N. Warr; D. Weisshaar; M. Zielinska
• Department/s: Nuclear physics
• Publishing year: 2007
• Language: English
• Publication/Series: Physical Review Letters
• Volume: 98
• Issue: 7
• Links: http://dx.doi.org/10.1103/PhysRevLett.98.072501
• Document type: Journal article
• Publisher: American Physical Society
• Topic: Subatomic Physics
• Status: Published
• ISBN/ISSN/Other: ISSN: 1079-7114