Beta decay of Lu154 and Yb154

Using mass-separated sources, the -decay properties of Lu154 and Yb154 were investigated. Limits of Lu154 decay to the first 8+ and 6+ levels in Yb154 suggest a 7+ spin for the odd-odd parent; also delayed proton emission and an indication of delayed -particle emission were observed to follow Lu154 decay. The -decay branch of the -emitting nucleus Yb154 was identified for the first time by the observation of one intense 133.2-keV ray. This transition deexcites a 1+ 133.2-keV level in Tm154 which is fed by an allowed 0+1+ transition with a logft value of 3.6 0.3.