Importance of covariances for uncertainty estimates in measurement of radionuclide mixtures by multichannel counting

Multichannel counting is often used when samples containing a mixture of known radionuclides are measured. Solutions to this method have been presented but to our knowledge, none of them took into account the covariances for evaluating the uncertainty of measurement. This paper presents new solutions for estimating uncertainties in measurement of radionuclide mixtures by multichannel counting and shows that covariances may contribute significantly to uncertainty of measurement so that they must be evaluated.