Seaborg's Plutonium? A Case Study in Nuclear Forensics

Passive X-ray and gamma--ray analysis was performed on UC Berkeley's EH{\&}S Sample S338. The object was found to contain $^{239}$Pu. No other radioactive isotopes were observed. The mass of $^{239}$Pu contained in this object was determined to be 2.0 $+$- 0.3 $\mu $g. These observations are consistent with the identification of this object as containing the 2.77-$\mu $g PuO$_{2}$ (2.44 $\mu $g $^{239}$Pu) sample produced in 1942 and described by Glenn Seaborg and his collaborators as the first sample of $^{239}$Pu that was large enough to be weighed [1,2].\\[4pt] [1] G. T. Seaborg, ``The Plutonium Story,$'' $LBL-13492 (1981) and http://www.osti.gov/scitech/biblio/5808140.\\[0pt] [2] B. B. Cunningham and L. B. Werner, ``The First Isolation of Plutonium,'' Journ. Amer. Chem. Soc. \textbf{71(5)} 1521-1528 (1949).