New lifetime measurements in Pd-109 and the onset of deformation at N=60

作者：Bucher B^*; Mach H; Aprahamian A; Simpson G S; Rissanen J; Ghita D G; Olaizola B; Kurcewicz W; Aysto J; Bentley I; Eronen T; Fraile L M; Jokinen A; Karvonen P; Moore I D; Penttila H; Reponen M; Ruchowska E; Saastamoinen A; Smith M K; Weber C

来源：Physical Review C, 2015, 92(6): 064312.

DOI：10.1103/PhysRevC.92.064312

Several new subnanosecond lifetimes were measured in Pd-109 using the fast-timing beta gamma gamma (t) method. Fission fragments of the A = 109 mass chain were produced by bombarding natural uranium with 30 MeV protons at the Jyvaskyla Ion Guide Isotope Separator On-Line (IGISOL) facility. Lifetimes were obtained for excited states in Pd-109 populated following beta decay of Rh-109. The new lifetimes provide some insight into the evolution of nuclear structure in this mass region. In particular, the distinct structure of the two low-lying 7/2(+) states occurring systematically across the Pd isotopic chain is supported by the new lifetime measurements. The available nuclear data indicate a sudden increase in deformation at N = 60 which is related to the strong p-n interaction between pi g(9/2) and vg(7/2) valence nucleons expected in this region.

• 出版日期2015-12-14