EVEN-PARITY BANDS OF Ru-108,Ru-110,Ru-112

High-spin, even-parity bands in neutron-rich Ru-108,Ru-110,Ru-112 nuclei were reinvestigated and considerably expanded by measuring many-fold prompt.-ray coincidence events following the spontaneous fission of Cf-252 with Gammasphere. Our high statistics data allow us to detect weaker transitions and bands not previously published. Also, gamma branching ratios, which are important for theory, are carefully measured from all levels. In Ru-110, we find a doubling of levels for both ground and quasi-gamma bands above the 8(+) levels. There are likely two-phonon quasi-gamma bands in Ru-110,Ru-112, as well as a bandhead level in Ru-108. The odd-even spin energy band staggering observed in the quasi-gamma bands in Ru-108,Ru-110,Ru-112 and the doubling of levels in Ru-110 present a challenge to theory.