DECAY OF MASS-SEPARATED TL-197 (2.83-H) TO HG-197

The decay of Tl197 to Hg197 has been studied with mass and radiochemically separated sources. Multiscaled singles spectra of γ rays, x rays, and conversion electrons; and, γ-γ and γ-x coincidences were obtained. The half-life of Tl197 was measured to be 2.83 ± 0.15 hours. A decay scheme has been constructed that incorporates 99.95% of the decay intensity assigned to Tl197. The ground state feeding is deduced to be 53 ± 12% of all decays. A level of 1009 keV is observed to decay by an E0 transition to the 12- ground state. The Hg197 level scheme is compared with recent particle-vibrator models. RADIOACTIVITY Tl197 [from W (O16,pxn), E=143 MeV; Pb197 decay, from W (O16, xn), E=143 MeV, Re (O16, pxn), E=129,141 MeV]; mass and radiochemically separated sources. Measured T12, Eγ, Iγ, Ice, Ix, γγ-coin., γx-coin., ICC. Deduced Iβ, log ft, β+EC, Hg197 deduced levels, J, π, γ-mult. Ge(Li), Si(Li). © 1979 The American Physical Society.