High-spin excitations in Ru nuclei near N=60

The level structures of several Ru isotopes near A = 104 have been studied in the fission of the compound nucleus Pb-197, formed in the Mg-24 + Yb-173 reaction at 134.5 MeV. A sequence of five transitions, observed in coincidence with known transitions in the Sr-86 and Sr-87 complementary fragments, has been assigned to Ru-105. Comparison with the neighboring odd-mass Ru isotopes supports assignment of this sequence as built on the h(l1/2) excitation in Ru-105. Th, positive-parity band built on the 7/2(+) state of Ru-103 has been extended above the backbending induced by the alignment of two h(l1/2) neutrons. In addition, the ground-state bands of Ru-104 and Ru-106 have been extended to higher spins. [S0556-2813(98)04110-7].