APPLICATION OF CORRELATIVE MICROSCOPY IN THE IDENTIFICATION OF URANIUM-BEARING MICROPARTICLES

摘要

This paper demonstrates the capabilities of a new core instrument for correlative microscopy analyses of micrometre-sized particles. It is a Tescan Lyra3 scanning electron microscope equipped with all major types of imaging detectors: in-beam SE and BSE, scintillation BSE and SE, as well as an EDS and an EBSD. A major distinction of this instrument is the time-of-flight mass spectrometry extension. The large sample chamber further hosts a residual gas analyser and RF plasma cleaner. A number of instruments revolve around this central hub: a Zeiss Z2m optical microscope, a HORIBA u-Raman spectrometer and an MMI laser micro-dissection microscope. By means of correlative microscopy techniques, the ex-situ identification and characterisation of the same uranium-bearing micro-artefact of safeguards interest (particle of interest or POI) is further extended to a laser ablation inductively coupled mass spectrometer and a large geometry secondary ion mass spectrometer, all located at the Office of Safeguards Analytical Laboratories (SGAS) in Seibersdorf, Austria. This methodological setup was developed in such a way that the POIs could also be analysed using external micro-analytical instruments such as μ-XANES and NEXAFS at synchrotron facilities.