Neutron deficient radioactive isotopes of tantalum have been produced by bombardment of lutetium with $\alpha$-particles, of hafnium with 10 Mev protons, and of tantalum with fast neutrons and protons from 10 to 70 Mev energy. In addition, wolfram isotopes produced by 10 to 70 Mev proton bombardments of tantalum, together with their respective tantalum daughter activities were studied. The radiation characteristics of the new activities of tantalum and wolfram are described.

• Received 12 June 1950

DOI:https://doi.org/10.1103/PhysRev.80.495