Measurement of lifetimes in Fe-62,Fe-64, Co-61,Co-63, and Mn-59

作者：Klintefjord M; Ljungvall J; Gorgen A; Lenzi S M; Garrote F L Bello; Blazhev A; Clement E; de France G; Delaroche J P; Desesquelles P; Dewald A; Doherty D T; Fransen C; Gengelbach A; Georgiev G; Girod M; Goasduff A; Gottardo A; Hadynska Klek K; Jacquot B; Konstantinopoulos T; Korichi A; Lemasson A; Libert J; Lopez Martens A; Michelagnoli C; Navin A; Nyberg J; Perez Vidal R M; Roccia S; Sahin E; Stefan I; Stuchbery A E

来源：PHYSICAL REVIEW C, 2017, 95(2): 024312.

DOI：10.1103/PhysRevC.95.024312

Lifetimes of the 4(1)(+) states in Fe-62,Fe-64 and the 11/2(1)(-) states in Co-61,Co-63 and Mn-59 were measured at the Grand Accelerateur National d'Ions Lourds (GANIL) facility by using the Advanced Gamma Tracking Array (AGATA) and the large-acceptance variable mode spectrometer (VAMOS++). The states were populated through multinucleon transfer reactions with a U-238 beam impinging on a Ni-64 target, and lifetimes in the picosecond range were measured by using the recoil distance Doppler shift method. The data show an increase of collectivity in the iron isotopes approaching N = 40. The reduction of the subshell gap between the nu 2p(1/2) and nu 1g(9/2) orbitals leads to an increased population of the quasi-SU(3) pair (nu 1g(9/2), nu 2d(5/2)), which causes an increase in quadrupole collectivity. This is not observed for the cobalt isotopes withN < 40 for which the neutron subshell gap is larger due to the repulsive monopole component of the tensor nucleon-nucleon interaction. The extracted experimental B(E2) values are compared with large-scale shell-model calculations and with beyond-mean-field calculations with the Gogny D1S interaction. A good agreement between calculations and experimental values is found, and the results demonstrate in particular the spectroscopic quality of the Lenzi, Nowacki, Poves, and Sieja (LNPS) shell-model interaction.

• 出版日期2017-2-9
• 单位中国地震局