Passive X-ray and gamma-ray analysis was performed on a curious sample from UC Berkeley's Hazardous Material Facility inventory, and the object was found to contain Pu-239. No other radioactive isotopes were observed. The mass of Pu-239 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 PuO2 (2.44 mu g Pu-239) sample produced in 1942 and described by Seaborg and his collaborators as the first sample of Pu-239 that was large enough to be weighed. (C) 2015 American Association of Physics Teachers.
展开▼
