Decay of Lu170 to Levels in Yb170

The locations of 70 energy levels in $^{170}\mathrm{Yb}$ were deduced from Compton-suppressed $\ensuremath{\gamma}$-ray singles, three-crystal $\ensuremath{\gamma}$-ray pair, conversion-electron, and Ge(Li)-Ge(Li) $\ensuremath{\gamma}\ensuremath{-}\ensuremath{\gamma}$ coincidence measurements on the electron-capture-${\ensuremath{\beta}}^{+}$ decay of $^{170}\mathrm{Lu}$. Both chemically separated and isotopically separated sources of $^{170}\mathrm{Lu}$ were used in collecting the data. A total of 550 $\ensuremath{\gamma}$-ray transitions have been observed in the $^{170}\mathrm{Lu}$ decay spectrum, 220 of which are definitely assigned to the $^{170}\mathrm{Yb}$ level scheme from 112 coincidence spectra. These definitive transitions account for 93% of the total observed $\ensuremath{\gamma}$-ray intensity. An additional 118 $\ensuremath{\gamma}$-ray transitions were placed on the basis of excited-state energy differences. Eight $E0$ transitions were observed in the conversion-electron data. Each of four excited ${0}^{+}$ states identified has less than 1% $\ensuremath{\beta}$ decay feeding from the ${0}^{+}$ parent. Spin and parity assignments are proposed for 46 levels in addition to the ground-state rotational band members. The $^{170}\mathrm{Yb}$ level structure is compared with available theoretical calculations, and a preliminary interpretation of several features of the decay scheme is presented.