Investigation of A=152 radioactivities with mass-separated sources: Identification of Lu152

Nuclides with A=152 were produced in Ni58 bombardments of Ru96 and their decay properties were investigated following on-line mass separation. The isotope Lu152 (T1/2=0.70.1 s) was identified by rays in its -decay daughter, Yb152. Based on its decay characteristics, the parent state has a probable spin and parity assignment of (4,5,6-). Several new transitions were observed to follow the decays of Yb152 and the Tm152 low-spin isomer; they established previously unknown levels in both Tm152 and Er152. The additional rays in Yb152 decay reduce from 100% to 88% the direct feeding to the one excited state in Tm152 that had been known earlier. Nevertheless, the corresponding logft value is calculated to be 3.5, indicating that this is an allowed transition which connects the 0+ parent with a 1+ excited state in Tm152. By comparing the -decay rates of Dy148 and Ho152, and the - and -decay rates of Er152, an branch of 904 % was deduced for Er152.