Emission probability of the 66.7 keV γ transition in the decay of ${}^{171}\mathrm{Tm}$

The γ-emission probability of the 66.73 keV line in the decay of ${}^{171}\mathrm{Tm}$ has been experimentally determined using γ spectrometry and inductively coupled mass spectrometry. Using a set of two reference sources, namely ${}^{60}\mathrm{Co}$ as primary standard and ${}^{44}\mathrm{Ti}/{}^{44}\mathrm{Sc}$ in secular equilibrium as secondary standard, we were able to deduce the detection efficiency at 66.73 keV of the used γ-spectrometry setup. The emission probability of the 66.73 keV γ transition in the decay of ${}^{171}\mathrm{Tm}$ has been determined afterwards with a set of three radioisotopically pure ${}^{171}\mathrm{Tm}$ samples to be 0.159(5)%.

Figure 1

Superimposed γ spectra of the ${}^{60}\mathrm{Co}$, ${}^{44}\mathrm{Ti}/{}^{44}\mathrm{Sc}$, and ${}^{171}\mathrm{Tm}$ samples.