Application of a liquid scintillation counter to the measurement of tracing radioactivity in experiments on suspended matter uptake in aquatic environments

¹ Departamento de Fisica Atomica, Molecular y Nuclear, Facultad de Fisica, University of Seville, Apdo. 41060 Sevilla, Spain
² Departamento de Fisica 2, University of Seville, ETSA, Avda. Reina Mercedes s/n, 41012 Sevilla, Spain
³ Departamento de Fisica Aplicada 1, University of Seville, EUITA, Carretera de Utrera km 1, 41013 Sevilla, Spain

Abstract

The experiments on the study of the kinetic transfer coefficients of conservative and non-conservative radionuclides, in aquatic environments, need to determine radionuclide activity in large number of samples. Different radioactivity measurement techniques can be selected for analyses, but the liquid scintillation technique is preferred due to its easy sample treatment and its low time consumption. Samples are initially traced with a known activity of a selected radionuclide (²³⁹Pu, ²⁴¹Am or ⁹⁹Tc). The transference of radionuclides, from the water to the suspended matter, is studied through the determination of the residual activity in aliquots of water sample, which are successively collected with time. In this work, we present the experimental procedures used for the ²³⁹Pu, ²⁴¹Am and ⁹⁹Tc activity measurement by liquid scintillation counting, using a Wallac Quantulus 1220 spectrometer. Results of the application of this technique to traced water samples are also shown in this study.