Decay of mass-separated 156Yb

The isotope 156Yb was produced via the 147Sm(16O,7n) reaction and was mass separated with an on-line isotope separator. Its decay properties were studied by using γ-ray, x-ray, and α-particle detectors. The half-life and α decay energy extracted were found to agree with values from earlier α-decay investigations. In addition, the (EC+β+) decay of 156Yb was identified for the first time. This decay to 156Tm is accompanied by only one strong γ ray, an E1 transition of 115.2 +- 0.2 keV. It is proposed that, as in the case of the /sup 148,150,152/Dy decays to odd-odd terbium nuclei, essentially all of the 156Yb β decay proceeds to a 1+ level in 156Tm at approx.115 keV by an allowed transition, logftapprox.3.9. This 1+ level then depopulates to a 2- at or near the ground state. Alpha-decay branching ratios were deduced for 156Yb, 156Tm, 152Er, and 152Ho