Actinide imaging in environmental hot particles from Chernobyl by rapid spatially resolved resonant laser secondary neutral mass spectrometry

Radioactive particles, so-called hot particles, are of great importance in the risk assessment of environmental pollution and human health hazards. Since most of these particles are only a couple of micrometers in size and thus have correspondingly small atomic inventory, information on origin and composition is difficult to obtain. Many analytical methods do not give insight into isotopic details or require the complete use up of the particle. Resonant laser secondary neutral mass spectrometry (rl-SNMS) has been proven to be a well-suited method for quasi-non-destructive analysis of trace elements. The technique provides high suppression of isobaric interferences and high spatial resolution without necessitating extensive chemical preparation. To measure multiple elements, it is often necessary to switch between laser excitation schemes, requiring elaborate adaptation of the laser setup. Here we present a novel rL-SNMS system capable of multi-element measurements in short succession without any manual adjustment to the laser system. For demonstration, ten micrometer sized hot particles from the Chernobyl Exclusion Zone are analyzed and the obtained isotopic ratios of uranium, plutonium and americium are discussed.