Production and investigation of tungsten α emitters including the new isotopes, 165W and 166W

Neutron-deficient tungsten isotopes were produced by bombarding an enriched ¹⁵⁶Dy target with ¹⁶O ions accelerated in the Oak Ridge isochronous cyclotron. A gas-jet-capillary system was used to transport product nuclei to an area where their α-decay properties could be investigated. The data of Eastham and Grant concerning ^162,163,164W were confirmed. In addition, two new weak α groups were observed. On the basis of excitation functions, ¹⁴N + ¹⁵⁶Dy cross bombardments, and α-decay energy systematics they were assigned to the new isotopes ¹⁶⁵W and ¹⁶⁶W. Their decay properties are as follows: (1) ¹⁶⁵W, E_α=4.909+/-0.005 MeV, T₁₂=5.1+/-0.5 sec, and (2) ¹⁶⁶W, E_α=4.739+/-0.005 MeV, T₁₂=16+/-3 sec. RADIOACTIVITY ^{162,163,164,165,166}W; measured E_α, T₁₂; discovered new isotopes ^165,166W.