1. First direct lifetime measurement of the 2(1)(+) state in Zn-72,Zn-74: New evidence for a shape transition between N=40 and N=42 close to Z=28
- Author
-
Niikura, M., Mouginot, B., Franchoo, S., Matea, I., Stefan, I., Verney, D., Azaiez, F., Assie, Marlène, Bednarczyk, P., Borcea, Catalin, Burger, A., Burgunder, G., Buta, Anna, Caceres, L., Clement, Emmanuel, Coquard, L., de Angelis, G., de France, Gilles, Santos, F. de Oliveira, Dewald, Alfred, Dijon, A., Dombradi, Z., Fiori, E., Fransen, C., Friessner, G., Gaudefroy, L., Georgiev, G., Grèvy, Stéphane, Hackstein, Matthias, Harakeh, M. N., Ibrahim, F., Kamalou, O., Kmiecik, M., Lozeva, R., Maj, A., Mihai, C., Moeller, O., Myalski, S., Negoita, Florin, Pantelica, Dan, Perrot, L., Pissulla, Th., Rotaru, Florin, Rother, Wolfram, Scarpaci, J. A., Stodel, C., Thomas, Jean-Charles, Ujić, Predrag, and Research unit Nuclear & Hadron Physics
- Subjects
NUCLEAR-DEFORMATION ,EVEN ZN ,COEXISTENCE ,SCATTERING ,BEAM ,SPECTROMETER ,MULTIPLE COULOMB-EXCITATION ,GROUND-STATES ,GE ISOTOPES ,QUADRUPOLE-MOMENTS - Abstract
We report here the first direct lifetime measurement of the 2(1)(+) state in Zn-72,Zn-74. The neutron-rich beam was produced by in-flight fragmentation of Ge-76 at the Grand Accelerateur National dIons Lourds and separated with the LISE spectrometer. The 2(1)(+) state was excited by inelastic scattering and knock-out reaction on a CD2 target and its lifetime was measured by the recoil-distance Doppler-shift method with the Koln plunger device combined with the EXOGAM detectors. The lifetimes of the 2(1)(+) states in Zn-72,Zn-74 were determined to be 17.9(18) and 27.0(24) ps, which correspond to reduced transition probabilities B(E2; 2(1)(+)- GT 0(+)) = 385(39) and 370(33) e(2) fm(4), respectively. These values support the idea of a systematic maximum of collectivity at N = 42 for Zn, Ge, and Se nuclei. In addition, the available systematics in the neighboring nuclei point toward a transition from a spherical oscillator at N = 40 to complete gamma-softness at N = 42.
- Published
- 2012