Exposing all the decay paths of 152Eu and their probabilities

Abstract

Checking the 152Eu 13-year very complex decay scheme, the aim of this paper is the identification, followed by a graphical presentation of all its decay paths and their probabilities, based on the information about particles, emitted energies and probabilities. The decay path followed in the course of the decay process is defined by the cascade transitions from the parent ground state to the daughter ground state. They are 74 paths to the 152Gd ground state and 285 to 152Sm, totalizing 359 cascades. As the decay path is seen as a time-series, the probability to follow this path, calculated here by an excel spreadsheet, can simply be seen as a product of transition probabilities. All such data is necessary for the accurate primary standardization of 152Eu solution through methods as the CIEMAT/NIST for liquid scintillation counting or even the sum peak method, an absolute measurement technique used for activity standardization by gamma-ray spectrometry techniques. The idea is to expose and highlight the difficulties arising from the complexity of such decay, meeting the needs of a didactic presentation to the user community not specifically available in the literature.