Evidence for the doubly magic structure of123Sn

The half lives of the levels at 4,714 keV and 4,415 keV in¹³²Sn have been determined to (20.2±0.8) ns and (4.0±0.3) ns, respectively. The half life of the 4,415 keV level in connection with the existence of aγ transition from this level into the ground state furnishes evidence for the doubly magic character of this nucleus. The transition probabilities which result from both half lives agree well with the theoretical predictions and, thereby, provide information on the structure of the positive parity states in¹³²Sn.