Radioactivity of Astatine Isotopes

Abstract

A number of new neutron deficient isotopes of astatine have been identified in the mass number range 200 to 209 following the irradiation of bismuth with high energy helium ions. Their alpha-decay properties fall in line with predictions for isotopes in this region with less than 126 neutrons; that is, the alpha-energies increase with decrease in mass number. Because of the complexity of the isotopic mixtures, half-lives and mass number assignments were made, in most cases, through the identification of decay products of lower atomic number. The decay properties as now known are summarized.