Alpha Decay Of The New Neutron-Deficient Isotope Ac-205

The newneutron-deficient isotope Ac-205 was synthesized in the complete-fusion reaction Tm-169(Ca-40, 4n)Ac-205. The evaporation residues were separated in-flight by the gas-filled recoil separator SHANS in Lanzhou and subsequently identified by the alpha-alpha position and time correlation method. The alpha-decay energy and half-life of Ac-205 were determined to be 7.935(30) MeV and 20(-9)(+97) ms, respectively. Previously reported decay properties of the ground state in Ac-206 were confirmed.