Investigation ofA=152radioactivities with mass-separated sources: Identification ofLu152

Nuclides with A=152 were produced in ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$ bombardments of ${}_{}{}^{96}{}_{}{}^{}\mathrm{Ru}$ and their decay properties were investigated following on-line mass separation. The isotope ${}_{}{}^{152}{}_{}{}^{}\mathrm{Lu}$ ($T_{1/2}$=0.7±0.1 s) was identified by γ rays in its β-decay daughter, ${}_{}{}^{152}{}_{}{}^{}\mathrm{Yb}$. Based on its decay characteristics, the parent state has a probable spin and parity assignment of (4,5,$6^{\mathrm{-}}$). Several new transitions were observed to follow the β decays of ${}_{}{}^{152}{}_{}{}^{}\mathrm{Yb}$ and the ${}_{}{}^{152}{}_{}{}^{}\mathrm{Tm}$ low-spin isomer; they established previously unknown levels in both ${}_{}{}^{152}{}_{}{}^{}\mathrm{Tm}$ and ${}_{}{}^{152}{}_{}{}^{}\mathrm{Er}$. The additional γ rays in ${}_{}{}^{152}{}_{}{}^{}\mathrm{Yb}$ decay reduce from 100% to 88% the direct feeding to the one excited state in ${}_{}{}^{152}{}_{}{}^{}\mathrm{Tm}$ that had been known earlier. Nevertheless, the corresponding logft value is calculated to be 3.5, indicating that this is an allowed β transition which connects the $0^{+}$ parent with a $1^{+}$ excited state in ${}_{}{}^{152}{}_{}{}^{}\mathrm{Tm}$. By comparing the β-decay rates of ${}_{}{}^{148}{}_{}{}^{}\mathrm{Dy}$ and ${}_{}{}^{152}{}_{}{}^{}\mathrm{Ho}$, and the α- and β-decay rates of ${}_{}{}^{152}{}_{}{}^{}\mathrm{Er}$, an α branch of 90±4 % was deduced for ${}_{}{}^{152}{}_{}{}^{}\mathrm{Er}$.