Decay studies of neutron-deficient odd-mass At and Bi isotopes

Alpha-decay properties of the isotope 191At were investigated for the first time and the decay properties of 193At and 195At were studied with improved accuracy. The nuclei were produced in fusion-evaporation reactions of 54Fe and 56Fe ions with 141Pr and 142Nd targets. The fusion products were separated in-flight using the gas-filled recoil separator RITU and implanted into a position-sensitive silicon detector. The isotopes were identified using position, time and energy correlations between the implants and subsequent alpha decays. New information concerning the low-lying states in the corresponding alpha-decay daughter nuclei 187Bi, 189Bi and 191Bi was also gained using alpha-gamma coincidences.