Expert performing isotopic measurements on uranium particles with Secondary Ion Mass Spectrometer (SIMS) at the Seibersdorf Analytical Laboratory in Austria.

(Source: Dean Calma/IAEA)

A technique for measuring the isotopic composition of nuclear material in micrometer size environmental particles by mounting them on a conducting substrate and bombarding them in vacuum with energetic ions. This results in the ejection of secondary ions which are analyzed by a mass spectrometer to measure the isotopic composition of uranium and plutonium in the particle.