Nuclear forensics: searching for nuclear device debris in trinitite-hosted inclusions

This study documents the 3D morphology of trinitite-hosted metallic inclusions and the first observations of alloys consisting primarily of Pb, Ta, Ga, and W. Scanning electron and backscatter electron imaging, as well as energy dispersive X-ray spectra chemical composition data are reported for heavy metal inclusions in 14 different samples of trinitite. Inclusions consisting of Fe–Ti–Si are the most abundant and presumably derived predominantly from the explosion tower. Grains of Cu, Pb, Ta + Ga + W were also observed and are likely derivatives of the trinitite device wiring, tamper, and tamper and core, respectively. Additionally, a Ba-rich grain and multiple zircons (ZrSiO4) were observed in a large majority of samples. The spherical morphology and the ubiquitous positioning of the heavy metal inclusions on the crater walls of the glassy trinitite surfaces indicate a two-step formation. Stage one involves formation of the glassy trinitite, while the second stage involved the precipitation of the inclusions that were incorporated onto the surface of the trinitite. Furthermore, the precarious positioning of these inclusions further emphasizes the need for analysis using non-destructive techniques prior to methods employing a bulk sample digestion approach.