The 1333.1 and 1559.4 keV isomers in 176Hf

The half-lives of the 1333.1 and 1559.4 keV isomers in 176 Hf have been determined to be 9.5 ± 0.2 and 9.8 ± 0.2 μs respectively. The upper isomer feeds the lower by means of a 226.25 ± 0.06 keV (M2) transition and a 53.49 ± 0.07–172.75 ± 0.04 keV cascade. The multipolarities of the members of the cascade are E1 and {M1(76 ± 13%) + E2(24 ± 13%)} respectively. Because it is fed from the upper state, the 1333.1 keV state appears to decay with a half-life significantly longer than its true value. The half-life of this state was therefore determined by using a TAC to measure the elapsed time between the detection of a gamma ray feeding the state and one deexciting it.