Experiment for synthesis of neutron-deficient protactinium isotopes

The complete fusion reaction Ca-40+Lu-175 was studied at a beam energy of 5.1 MeV u(-1). Evaporation residues recoiled from the target were separated from the primary beam by the gas-filled recoil separator SHANS and then implanted into the focal plane detection system. Based on the energy-position-time correlation measurement, neutron-deficient nuclei Ac208-213, Pa-212 and Th-211 produced in this reaction were identified. Previously reported decay properties of the ground state in Pa-212 were confirmed and improved values of 5.1(-1.7)(+5.1) ms and 8.250(20) MeV for the half-life and alpha-particle energy of Pa-212 were obtained. No correlated decay chain arising from Pa-211 was observed and an upper limit for the cross section of Pa-211 was estimated.