Low Angular Momentum States Populated in the Decay of 178Lu

The low angular momentum states in 178Hf populated in the beta decay of the low spin state (T1/2 = 30 min) of 178Lu are investigated with both high resolution and high efficiency Ge(Li) detectors as well as a NaI(Tl)–Ge(Li) (γ,γ) coincidence system. The sources of 178Lu were produced through the 178Hf(n,p) and 181Ta(n,α) reactions on natural targets of hafnium and tantalum, respectively, using 14.8 MeV neutrons. Sixteen gamma transitions in the energy range 1090.8 to 1730.0 keV have been found to decay with the 30 min period of 178Lu. A decay scheme of 178Lu has been proposed with the excited levels in 178Hf at 93.17(2+), 306.59(4+), 1309.7(0+, 1±), 1362.7(0+, 1±, 2+), 1434.2(0+), 1442.9(0+), 1496.7(2+), 1514.2(2+), 1562.0(2+), 1772.1(0+, 1±, 2+), and 1823.2(0+, 1±, 2+) keV. The weak β-branching ratios and their log ft values are deduced from the observed γ-ray intensities and results thus obtained are discussed.