Radioactive Decay ofLu168

Ytterbium oxide enriched to 30.9% in the 168 mass number was irradiated with 6-Mev protons. An activity decaying by electron capture with a half-life of 7.1±0.2 minutes was produced and assigned to ${\mathrm{Lu}}^{168}$. The activity consists of gamma rays with energies of 87±1, 900±7, 987±7, 1410±20, 1800±40, 2130±60 kev in addition to the ytterbium $K$ x ray. An energy level scheme for this decay is presented.