A rapid method for simultaneously determining activity of ⁸⁹Sr and ⁹⁰Sr in a non-equilibrated ⁹⁰Sr/⁹⁰Y system without Cerenkov counting

A method for determining activity of ⁸⁹Sr and ⁹⁰Sr in a sample where ⁹⁰Sr and ⁹⁰Y are not in equilibrium is presented. The method consists of an experimental design and equations for accurately calculating activity of ⁸⁹Sr and ⁹⁰Sr based on ⁹⁰Y β particle counts and the total counts of β particles emitted from ⁸⁹Sr, ⁹⁰Sr, and ⁹⁰Y in a sample. The equations are derived based on chemical separation sequences, β particle counting sequences, and the Bateman equation. The presented method allows simultaneously obtaining the activity of ⁸⁹Sr and ⁹⁰Sr in a non-equilibrated ⁹⁰Sr/⁹⁰Y system without the need of Cerenkov counting.