Level structure and band mixing in 232U

Abstract

The energy and relative intensities of gamma transitions in 232 following the radioactive decay of 1.3 d 232Pa. have been measured with a Ge(Li) spectrometer and with the Caltech bent crystal spectrometer. Relative intensities of internal conversion electrons have been measured with a Si(Li) detector. Coincidence measurements have also been made using NaI and Ge(Li) detectors. The following rotational bandheads have been established: octupole vibrational band ( K π = 0 − at 563.2 keV),β-band (0 + at 691.3 keV), γ-band(2 + at 866.7kev) and two negative parity bands (2 − at 1016.8 kev) and (1 −? at 1132.4 keV). Transitions from the γ-band to the ground state band are in good agreement with a single parameter band mixing model, with z 2 = 0.025 ± 0.005. However, the relative B(E2) for the 2 γ−0 β transition is five times that for the 2 γ−0 g.s. transition. Good agreement with predictions of the rotational model for the E1 transitions from the octupole O − band to the ground state band has been found. There is evidence for strong mixing of the proposed negative parity bands at higher energy.