Level structure of Ac221 and Fr217 from decay spectroscopy, and reflection asymmetry in

Abstract

225 Pa and 221 Ac were produced at the IGISOL facility through proton-induced fusion-evaporation reactions and have been studied using α-particle spectroscopy, as well as α-γ and α-electron coincidence spectroscopy. The level scheme of 221 Ac, daughter of 225 Pa, and of 217 Fr, daughter of 221 Ac were reconstructed. An interpretation of 221 Ac levels as K = 5/2 ± and K = 3/2 ± parity-doublet bands is proposed. Such bands appear in reflection-asymmetric models and would be an indication of a static reflection asymmetric shape for 221 Ac.