SIMS Analyses of Aerodynamic Fallout from a Uranium-Fueled Test

Lewis, L. A.¹  Univ. of California, Berkeley, CA (United States)]  Knight, K. B.¹  Matzel, J. E.² 

[1] Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States);Lawrence Liver

关键词: SIMS;    trinitite;    fallout;    device debris;    nuclear forensics;   

DOI  :  10.2172/1252626
RP-ID  :  LLNL-TR--660055
PID  :  OSTI ID: 1252626

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来源: SciTech Connect

【 摘 要 】

Five silicate fallout glass spherules produced in a uranium-fueled, near-surface nuclear test were characterized by secondary ion mass spectrometry, electron probe microanalysis, autoradiography, scanning electron microscopy, and energy-dispersive x ray spectroscopy. Several samples display distinctive compositional heterogeneity suggestive of incomplete mixing, and exhibit heterogeneity in U isotopes with 0.02 < ²³⁵U/ ²³⁸U < 11.8 among all five samples and 0.02 < ²³⁵U/ ²³⁸U < 7.81 within a single sample. In two samples, the ²³⁵U/ ²³⁸U ratio is correlated with major element composition, consistent with the agglomeration of chemically and isotopically distinct molten precursors. Two samples are quasi-homogeneous with respect to composition and uranium isotopic composition, suggesting extensive mixing possibly due longer residence time in the fireball. Correlated variations between ²³⁴U, ²³⁵U, ²³⁶U and ²³⁸U abundances point to mixing of end-members corresponding to uranium derived from the device and natural U ( ²³⁸U/ ²³⁵U = 0.00725) found in soil.