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Title: ACCURATE QUANTIFICATION OF RADIOACTIVE MATERIALS BY X-RAY FLUORESCENCE: GALLIUM IN PLUTONIUM METAL.

Conference ·
OSTI ID:801231

Determining the concentration of gallium in plutonium metal is imperative in manufacturing nuclear weapons. X-ray fluorescence (XRF) is an effective method used to quantify the gallium content in plutonium; however, the sample and specimen preparation methods currently employed could be improved from a time and safety standpoint. Recently, a dried residue specimen preparation method was developed as an alternative to the established aqueous approach. The method currently certified to prepare plutonium for gallium analysis by XRF involves dissolving the sample and removing the plutonium with ion exchange chromatography. The gallium remaining in solution is then analyzed. This method has been thoroughly developed, and relative accuracy and precision values less than 1% can be achieved. However, this process is time consuming, and the specimen solution is radioactive due to the presence of residual plutonium and trace americium. Thus, an alternate process was developed to avoid these issues in which the plutonium solution is cast in {mu}L spots on Mylar XRF film, dried, and sealed inside a sample cell for analysis. This specimen preparation method is considerably faster and also safer than the solution process. Previous studies have demonstrated that a very linear calibration can be obtained from dried residue standards. In the present work, accuracy and precision results will be compared from using the aqueous and dried residue specimen preparation methods. The strengths and limitations of each method will also be discussed. In summary, this work will illustrate both the challenges faced with analyzing radioactive materials by XRF and the high accuracy and precision achievable with proper sample and specimen preparation.

Research Organization:
Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
Sponsoring Organization:
US Department of Energy (US)
DOE Contract Number:
W-7405-ENG-36
OSTI ID:
801231
Report Number(s):
LA-UR-02-5596; TRN: US200312%%252
Resource Relation:
Conference: Denver X-Ray Conference 2002, Colorado Springs, CO (US), 07/29/2002; Other Information: PBD: 4 Sep 2002
Country of Publication:
United States
Language:
English