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Analytical Processes
Thermal Ionization Mass Spectroscopy

TIMS Sample Preparation

Alpha-Spec Pu Sample Preparation - Separation

Alpha-Spec Pu Sample Preparation - Electroplating

Plutonium Analysis by Alpha-Spectrometry


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The solution is electroplated onto a rhenium filament, which is inserted into the ion source of the mass spectrometer. A current is passed through the filament, which causes the plutonium isotopes in the sample to ionize. The ions are accelerated through a magnetic field, resulting in separation of the ions by mass, with heavier ions having more momentum. An electron multiplier allows the number of ions of each isotope to be counted. The amount of Pu-239 in the original sample is calculated by comparing the number of those ions to those resulting from a known amount of Pu-242 spike. The Pu-242 tracer was added to the sample prior to electroplating. These operations are conducted in a Clean Room environment, and there are two mass spectrometers available for sample analysis. The nominal detection limit for this analytical method is 0.5 fCi/l. Approximately 1,000 samples, plus QCs, are analyzed per year for the LANL Bioassay Project.