Half-life of the 1552 keV level in 234U

Abstract The half-life of the 1552 keV level in 234 U was measured in the decay of 6.7 h 234 Pa by delayed coincidences with a time-to-amplitude converter to be 2.20±0.25 ns. This half-life determines the transition probability of the 131 keV E1 transition between the two neutron states 5 + { 5 2 + [622]↑+ 5 2 + [633]↓} and 6 − { 7 2 − [743]↑+ 5 2 + [633]↓} . The hindrance factors ( F W = 3.5 × 10 4 and F N = 0.27) are compared to those of the E1 transition between the same Nilsson states in the odd-mass nucleus 239 Pu ( F W = 2.2 × 10 6 and F N = 13). The difference of the reduced transition probabilities is discussed in terms of pairing interactions. It was confirmed that the 1552 keV level is only depopulated by the 131 keV E1 transition.