Decay of 170Ho isomers to levels in 170Er

Beta- and gamma-rays emitted in the decay of 170 Ho isomers have been studied with Ge(Li), NaI(Tl) and plastic detectors. Sources were prepared by the 170 Er(n, p) 170 Ho reaction with about 15 MeV neutrons. Fifty γ-rays have been observed and thirty-six of them are assigned to the 170 Er level scheme including seven new levels at 1010.5, 1217.3, 1900.5, 1982.6, 2039.3, 2684.8 and 3606.2 keV. The most probable spin assignments of 1 ± and 4 ± are proposed for the 43 sec and 2.8 min 170 Ho, respectively. Both Q β values are 4.0±0.2 MeV. The K =0 assignment for the 2 + state at 959.8 keV is proposed from the E2 branching rations to the ground-state band. It is found that the relative B (E2) values from γ-vibrational band can not be explained by a single value of the band mixing parameter z 2.