Nuclear forensic methods

Abstract A short history and treatment of the various aspects of nuclear forensic analysis is followed by a discussion of the most common chemical procedures, including applications of tracers, radioisotopic generators, and sample chronometry. Analytic methodology discussed includes sample preparation, radiation detection, various forms of microscopy, and mass-spectrometric techniques. The chapter concludes with methods for the production and treatment of special nuclear materials and with a description of several actual case studies conducted at Livermore. 

The solvent extraction method with which the analytical chemist is most familiar involves placing both liquid phases in a separatory funnel and agitating by hand to effect the partition due to issues of contamination control and limited solution volumes, this implementation is little used in nuclear forensic analysis. Often, phases are mixed in a capped centrifuge cone using a vortex mixer this is particularly convenient in a gloved box, where the loss of manual dexterity impedes the manipulation of a separatory funnel and stopcock. Phase separation is facilitated through the use of a centrifuge. 

Using a variety of techniques, the radiochemical analyst measures the concentrations of various radioactive and stable nuclides in a nuclear forensic sample. The resultant table of concentrations is the radioanalytical fingerprint of the sample. However, unlike an actual fingerprint, which is interpreted by comparison with a database, the fingerprint of a sample of special nuclear material is forged by the methods used in its creation, and information about the origin of the material can be obtained from scientific principles by the informed analyst. 

Analytic methods for nuclear forensic analysis (adapted from Kristo et al. 2006)... 

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