The new isotope Th.

The new neutron-deficient isotope Th was produced in the complete-fusion reaction Ni + Sm $ \rightarrow$Th + 3n . Evaporation residues were separated in-flight by the velocity filter SHIP and subsequently identified on the basis of energy-, position- and time-correlated $ \alpha$ -decay chains. The measured $ \alpha$ -decay energy and half-life value of Th are 8044(30)keV and 1.7 ms, respectively. Improved data on the $ \alpha$ -decay of Th , Th , Th and Ra were obtained using complete-fusion reactions of Ni with Sm , Sm , and Sm targets. [ABSTRACT FROM AUTHOR]