Study of XK and gamma photon emission following decay of 154Eu.

A joint project has been established between VNIIM (D.I. Mendeleyev Institute for Metrology) and LNHB (Laboratoire National Henri Becquerel) to determine as accurately as possible the X- and gamma-ray emission probabilities of 154Eu. Point sources were prepared by VNIIM, and absolute measurements of activity per unit mass were undertaken by both laboratories using coincidence, anti-coincidence and 4pi-gamma counting methods. Other point sources and one aliquot were also prepared for precise gamma-ray spectrometry measurements. Absolute photon emission probabilities were determined with a maximum uncertainty of 0.5% for the most intense lines, supporting the development of this nuclide as a multigamma standard.