Gamow-Teller decay of 142Te to 142I

Abstract

The beta decay of 142Te90 to 142I89 was investigated for the first time. The parent nucleus was produced by the in-flight fission of a 238U beam with an energy of 345 MeV per nucleon, impinging on a 9Be target at the Radioactive Isotope Beam Factory of RIKEN. Excited states in 142I were established by beta-delayed gamma-ray spectroscopy. The observed (1+) states in 142I could be interpreted to be predominantly the nu 0h9/2 (R) pi 0h11/2 configuration formed by a Gamow-Teller transition between a neutron in the 0h9/2 orbital and a proton in the 0h11/2 orbital. Additional features of the (1+) states are discussed by comparing with neighboring heavier isotones, such as 144Cs and 146La. In the context of deformed shell-model calculations, the (1+1 ) state is closely related to the nu[5, 3, 2]3/2 (R) pi[5, 5, 0]1/2 configuration, which may be related to the weak Gamow-Teller transition strength.