Incrustation of alpha-particle emitters in the source backing: influence on activity measurements

Resumen

Alpha particles emitted from radioactive sources are often measured using a 2pi counting geometry in order to determine the activity with a low deviation. The ratio C2pi/A (counting rate/activity) can, however, deviate from the theoretical value of 0.5 because of backscattering in the backing material, scattering and absorption of alpha particles in the source. The experimental counting rates are, therefore, corrected for these effects (backscattering for all sources, plus self-absorption for sources of non-negligible thickness) to determine the real source activity. However, the corrections needed for situations corresponding to alpha-particle sources in which the radionuclides are not deposited but incrusted in the backing material have not been considered. The aim of the present work was therefore to study the influence that incrustation in the backing can have on the total detection efficiency, and hence on the activity estimated for the source. To this end, we used the Monte Carlo computer code SRIM to model the behaviour of the alpha particles in the backing material.

Alfonso Fernandez Timon

Profesor Titular de Universidad

Alfonso Fernández Timón es Profesor Titular de Universidad y unos de los investigadores seniors del Grupo de Investigación en Algoritmos de Optimización GRAFO de la Universidad Rey Juan Carlos. Anteriormente fue Becario de la Red de Estaciones Metrológicas y del Plan de Vigilancia Radiológica del CSN en la Universidad de Extremadura. Sus lineas de investigación abarcan desde la aplicación de metaheurísticas para resolver problemas de optimización combinatoria hasta la metrología de radiaciones nucleares.