Determination of Fe and Tb concentrations in geological and environmental samples using the instrumental neutron activation analysis method combined with the γ − γ coincidence technique

Abstract

The instrumental neutron activation analysis (INAA) method was combined with the γ − γ coincidence technique to measure Iron (Fe) and Terbium (Tb) concentrations in geological (Montana II Soil) and environmental (Coal Fly Ash) standard materials. The measured concentrations, which agree well with the corresponding certified values, are compared with those obtained from the traditional INAA method. It is demonstrated that employing the γ − γ coincidence technique slightly improves the accuracy of the analysis. Furthermore, the coincidence technique enhances the detection limits of Tb by ∼4.5 and ∼5.5 times in environmental and geological samples, respectively, but has almost no enhancement in those of Fe. The γ − γ coincidence technique therefore does not always promote the analysis quality of the INAA method, but it is effective for analyzing elements whose characteristic γ rays sustain a high Compton background and/or are overlapped with other γ rays.