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The structure of the odd-odd 232Ac nucleus, produced in the β– decay of 232Ra, was investigated through γ-ray spectroscopy at the ISOLDE Decay Station at ISOLDE, CERN. A radioactive beam of 232Fr was implanted in the IDS. The γ-rays originating from the β – decay chain 232Fr - 232Ra - 232Ac - 232Th were registered using a mixed array consisting of 4 HPGe Clover and 2 LaBr3(Ce) detectors arranged in a close geometry.
Prior to our study, only very limited information was available for the 232Ra - 232Ac β– decay coming from a study in 1986. In that experiment, the multinucleon transfer reaction was used to produce the precursor 232Ra. Due to low statistics and the absence of γ-γ coincidences, only a few γ-ray transitions were associated with 232Ac. In this work, we report a revised and considerably extended level scheme for 232Ac by ascribing 25 new γ-transitions that link 15 new excited states. An isomeric state at Ex=97.7 keV was identified and its lifetime was measured using the HPGe detectors. The experimental results will be discussed and compared with the available literature data for the neighbouring 230Ra β– decay.
