Coincidence Counting Techniques For The Determination of ²²⁶Ra Concentrations in Water

Abstract

<p>Three coincidence counting techniques for the assay of ²²⁶Ra in water samples are evaluated and compared. The techniques are based on the detection of alpha-gamma, beta-gamma, and gamma-gamma coincident radiations. Samples were prepared by co-precipitating ²²⁶Ra with barium sulphate. Details of this chemical procedure are presented in this thesis. The lower limit of detection, sensitivity to sample thickness, and system precision are investigated. Finally, two data analysis techniques, the method of Least Squares and the method of Maximum Likelihood, for determining -ray peak areas as applied to low counting rates, are discussed.</p>