Combinatory use of time-of-flight secondary ion mass spectrometry (SIMS) and sector-field SIMS for estimating elemental and isotopic compositions of nuclear forensic samples

Abstract

This paper describes an alternative approach to nuclear forensic analysis by employing time-of-flight (TOF) SIMS and sector-field (SF) SIMS collaboratively. A set of synthetic samples consisting of UO2 and other metal (Gd, Mo or Zr) oxide was analyzed by the both instruments. With TOF–SIMS, qualitative elemental analysis was possible in U-dominant or low-U samples. TOF–SIMS was also useful for investigating potential isobars for U isotopes induced by the other metals. To avoid the isobaric interferences, particle search and major U isotope analysis using SF–SIMS were performed by measuring UO2 + instead of U+, and thus the effects of interference were reduced.