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Title: Locating trace plutonium in contaminated soil using micro-XRF imaging

Micro-X-ray fluorescence (MXRF) was used to locate minute quantities of plutonium in contaminated soil. Because the specimen had previously been prepared for analysis by scanning electron microscopy, it was coated with gold to eliminate electron beam charging. However, this significantly hindered efforts to detect plutonium by MXRF. The gold L peak series present in all spectra increased background counts. Plutonium signal attenuation by the gold coating and severe peak overlap from potassium in the soil prevented detection of trace plutonium using the Pu Mα peak. However, the 14.3 keV Pu Lα peak sensitivity was not optimal due to poor transmission efficiency through the source polycapillary optic, and the instrument silicon drift detector sensitivity quickly declines for peaks with energies above ~10 keV. Instrumental parameters were optimized (eg. using appropriate source filters) in order to detect plutonium. An X-ray beam aperture was initially used to image a majority of the specimen with low spatial resolution. A small region that appeared to contain plutonium was then imaged at high spatial resolution using a polycapillary optic. Small areas containing plutonium were observed on a soil particle, and iron was co-located with the plutonium. Zinc and titanium also appeared to be correlated with themore » plutonium, and these elemental correlations provided useful plutonium chemical state information that helped to better understand its environmental transport properties.« less
Authors:
 [1] ;  [1] ;  [1] ;  [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
OSTI Identifier:
1221418
Report Number(s):
LA-UR--15-22161
Journal ID: ISSN 1097-0002
Grant/Contract Number:
AC52-06NA25396
Type:
Accepted Manuscript
Journal Name:
Advances in X-ray Analysis (CD-ROM)
Additional Journal Information:
Journal Name: Advances in X-ray Analysis (CD-ROM); Journal Volume: 58; Journal ID: ISSN 1097-0002
Publisher:
International Centre for Diffraction Data
Research Org:
Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY XRF plutonium trace environment