Emission probability measurement of 94.7 keV γ-ray for 165Dy

Emission probability of γ-ray is one of the most important decay parameters of radionuclide and improvement of certainty is desired in many fields of research and application. 165Dy decays to the ground or excited states of 165Ho with a half-life of 2.334 h and emits 55 γ-rays. The emission probability of the most intense 94.7 keV γ-ray is evaluated to be 3.6±0.4% in Nuclear Data Sheets (50 (1987) 137). To improve the certainty, measurement was carried out using a 4πβ–γ coincidence apparatus with two-dimensional data-acquisition system. The measured emission probability of 94.7 keV γ-ray was 3.80±0.05% that was larger than the evaluated value by about 5% and the uncertainty was greatly improved.