The 160.44 day 177mLu as a new gamma calibration standard

Gamma emissions in the decay of 160.44 day isomer 177mLu were analyzed with a 60 cc, coaxial HPGe detector. The energies and intensities of 50 gamma transition – 40 of which belong to the daughter 177Hf, that was excited by beta decay of the isomer, and 10 to the isomeric transition in 177Lu were precisely determined. These precise values have resulted in an internally consistent decay scheme for 177mLu. These gamma intensity and gamma emission probability measurements will help in making the long lived 177mLu available as a calibration standard for HPGe detectors and also for other applications.

► γ-Intensityγ-Intensity measurements in 177mLu decay taken for the first time with a 60 cc HPGe. ► Precision of about 1–3% in relative gamma intensities. ► Energy and intensities determined for all 50 transitions in the decay. ► Mixing ratio for all M1+E2 transitions. ► Precise measurement of γγ emission probabilities enabling 177mLu as a γγ calibration standard.