General activation and decay formulas and their application in neutron activation analysis with k_o standardization

A general formula for nuclear activation and decay is presented. Besides decay processes, it deals with burnup and successive activation. The representation is compact and has a structure comparable to the classical NAA formulas, used in absence of burnup and activation of daughter products. A solution is presented to the mathematical singularities appearing when different products have equal time constants. Explicit expressions are given for typical situations encountered in neutron activation analysis. Its incorporation into the k₀ standardization is demonstrated for several decay types.