Measurements of Cs-135/Cs-137 in debris from the Trinity nuclear test

Cs-135/Cs-137 measurements were performed on a set of debris samples from the first nuclear test, Trinity. Debris from several locations around ground zero of the event were purified and analyzed for Cs-135/Cs-137 by thermal ionization mass spectrometry (TIMS). The Cs-isotopic measurements presented here are the first high precision TIMS Cs-135/Cs-137 measurements of trinitite from variable locations and cooling histories relative to ground zero. Our measurements show a large fractionation from the predicted fission yields, all with a relative enrichment in Cs-137. Cs-135/Cs-137 ratios indicate that condensation times varied between different debris forms, however they are not consistent with an unfractionated decay to Cs from independent fission products. Variations in Cs-135/Cs-137 ratios are observed with relative distance from ground zero as well as Cs-135/Cs-137 heterogeneities between different trinitite lithologies within a single sample.

Automated summary

Cs-135/Cs-137 measurements were conducted on debris samples from the Trinity nuclear test, revealing variations in condensation times and Cs-135/Cs-137 ratios. The measurements also showed heterogeneities in Cs-135/Cs-137 ratios within different trinitite lithologies in a single sample.