Preparation of Standard Radioactive Solution of ¹⁵²Eu

¹⁵²Eu is an important radionuclide for the energy and efficiency calibration of the HPGe gamma-detector. The preparation procedure is as following: purification and identify for purity of ¹⁵²Eu , homogeneity test, stability test, and measurement. According to the statistical tools, the spot-check samples from the solution in ampoule are measured for homogeneity test by 4πβ(PPC)-γ. The minimum sample for spot-check foe measurement by 4πβ(PPC)-γ is about 10-40 mg solution. The solution in ampoule have been stored for one year, then the spot-check samples are measured for stability test by 4πβ(PPC)-γ, the results prove that the solutions are stable. The certified value was measured by different laboratories using different ways. The last result of ¹⁵²Eu is 499.1（1±0.5%）kBq/g（α=0.05）.