Gamma Spectrometry of Nuclear Material Samples

Gamma ray spectrometry is widely used in safeguards laboratories to measure the isotopic abundance of various U and Pu isotopes but also their concentration, as well as the concentration of alternative nuclear elements (see Sect. 14.4.4.8) fission and decay isotopes (Parus and Raab 1996 Parus et al. 1987). Laboratory applications make use of the developments of NDA technology mentioned in Sect. 63.3.1, but are usually part of DA procedures. 

The abundance of LEU products is determined with a total uncertainty of 0.13% (Is) by measuring the 186 keV gamma rays with a Nal or GeLi well detector on 5 ml solutions containing a well-known amount of uranium, close to 0.5 g. The volume of the sample and synthetic calibration test solutions, their acid and U concentrations are kept in a very narrow range so that the self-absorption and coimting geometry be constant factors or minor variations be accurately 

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