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Title: Measurements Conducted on an Unknown Object Labeled Pu-239

Measurements were carried out on 12 November 2013 to determine whether Pu-239 was present on an object discovered in a plastic bag with label “Pu-­239 6 uCi.” Following initial survey measurements to verify that the object was not leaking or contaminated, spectra were collected with a High Purity Germanium (HPGe) detector with object positioned in two different configurations. Analysis of the spectra did not yield any direct evidence of Pu-­239. From the measured spectra, minimum detectable activity (MDA) was determined to be approximately 2 uCi for the gamma-­ray measurements. Although there was no direct evidence of Pu-239, a peak at 60 keV characteristic of Am-­241 decay was observed. Since it is very likely that Am-­241 would be present in aged plutonium samples, this was interpreted as indirect evidence for the presence of plutonium on the object. Analysis of this peak led to an estimated Pu-­239 activity of 0.02–0.04 uCi, or <1x10-6 grams.
Authors:
 [1]
  1. National Security Technologies, LLC. (NSTec), Mercury, NV (United States)
Publication Date:
OSTI Identifier:
1171118
Report Number(s):
DOE/NV/25946--2302
TRN: US1600007
DOE Contract Number:
AC52-06NA26946
Resource Type:
Technical Report
Research Org:
National Security Technologies, LLC. (NSTec), Mercury, NV (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; PLUTONIUM 239; HIGH-PURITY GE DETECTORS; GAMMA SPECTRA; KEV RANGE; APPROXIMATIONS; PEAKS; RADIOMETRIC ANALYSIS