Experiment for synthesis of neutron-deficient protactinium isotopes

The complete fusion reaction 40 Ca+ 175 Lu 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-positiontime correlation measurement, neutron-deficient nuclei − 208 213 Ac, 212 Pa and 211 Th produced in this reaction were identified. Previously reported decay properties of the ground state in 212 Pa were confirmed and improved values of − + 5.1 1.7 ms and 8.250(20) MeV for the half-life and α-particle energy of 212 Pa were obtained. No correlated decay chain arising from 211 Pa was observed and an upper limit for the cross section of 211 Pa was estimated.