Decay ofTb162and the Excited States ofDy162

Sources of 7.5-min ${\mathrm{Tb}}^{162}$ were produced by the ${\mathrm{Dy}}^{162}\mathrm{}(n,p)\mathrm{}{\mathrm{Tb}}^{162}$ and ${\mathrm{Ho}}^{165}(n,\alpha ){\mathrm{Tb}}^{162}$ reactions with 14.8-MeV neutrons. The decay properties of ${\mathrm{Tb}}^{162}$ were investigated with the help of standard scintillation-counter techniques. In the beta- and gamma-ray measurements, the beta groups with end-point energies of 1.72±0.1 MeV (13%) and 1.45±0.1 MeV (87%), and the gamma rays with energies of 45±5, 80±5, 130±5, 185±10, 195±10, 265±5, 390±10, 630±10, 690±15, 810±10, 880±10, 890±10, 1070±15, and 1205±15 keV, all decaying with a half-life of 7.5 min, have been observed. The sum-spectrum and coincidence studies show that the following are gamma-ray cascades: 130-265-810-80; 130-265-890; 130-265-625-185-89; 130-195-880-80; 130-195-690-185-80; 130-1070-80; 395-810-80; 395-890; and 1205-80 keV. The beta-gamma coincidences taking each of the 80-, 810-, and 890-keV gamma rays as a gate show both of the above beta groups; while in those taking the 190- and 265-keV gamma rays as a gate, only a single beta group with the end-point energy of 1.45±0.1 MeV was observed. Based on these results, a decay scheme for ${\mathrm{Tb}}^{162}$ is proposed with levels in ${\mathrm{Dy}}^{162}$ at 890 ($2^{+},k=2\mathrm{}$), 924 ($8^{+},k=0\mathrm{}$), 960 ($3^{+},k=2\mathrm{}$), and 1155 keV ($2^{-},k=2\mathrm{}$) and is discussed in terms of the unified model.