Analysis of nuclear materials by energy dispersive X-ray fluorescence and spectral effects of alpha decay

Abstract

Energy dispersive X-ray fluorescence (EDXRF) spectra collected from alpha emitters are complicated by artifacts inherent to the alpha decay process, particularly when using portable instruments. For example, 239Pu EDXRF spectra exhibit a prominent uranium L X-ray emission peak series due to sample alpha decay rather than source-induced X-ray fluorescence. A portable EDXRF instrument was used to collect qualitative spectra from plutonium and americium, and metal alloy identification was performed on a Pu-contaminated steel sample. Significant alpha decay-induced X-ray fluorescence peaks were observed in spectra obtained from the plutonium and americium samples due to the 235U and 237Np daughters, respectively. The plutonium sample was also analyzed by wavelength dispersive XRF (WDXRF) to demonstrate that alpha decay-induced X-ray emission has a negligible effect on WDXRF spectra.