Activity Standardization of ¹⁵²Eu by Anti-coincidence Method

¹⁵²Eu has a complex decay scheme, which decays 27.9% by β-emission and 72.1% by electron capture. The nuclide emits more than 140 γ-rays which include 12 main γ-rays in the range of 122-1 408 keV. ¹⁵²Eu is an important radionuclide for the energy and efficiency calibration of the HPGe gamma-spectrometers. It is very important to study the absolute measurement methods of the activity. A solution of ¹⁵²Eu was absolutely standardized by the 4πβ(PPC)-γ(HPGe) anti-coincidence counting system and the results were compared with that by 4πβ-4πγ coincidence counting efficiency extrapolation, HPGe gamma-spectrometer and 4πγ high pressurized ionization chamber. It is shown that all the results from the above methods are in good agreements within the uncertainties.