UV laser‐induced fluorescence spectroscopy as a non‐destructive technique for mineral and organic detection in carbonaceous chondrites

Abstract

AbstractHere, we discuss the merits of non‐destructive UV laser‐induced fluorescence spectroscopy (LIF) as a flight or laboratory instrument to analyze organic and mineral material in samples on or returned from carbon‐rich asteroids such as (101955) Bennu by NASA’s OSIRIS‐REx mission. LIF is a unique instrument that is non‐destructive while acquiring data, and allows for no sample preparation, crushing, or cutting. This method provides spectral data indicative of specific minerals and organics in less time than Raman spectroscopy, and can be set up to produce 2‐D raster images of areas of interest. Furthermore, if an LIF system is set up with a gated CCD camera, time‐resolved fluorescence spectroscopy can be performed, providing a unique identification tool for organic and mineral contents using fluorescence decay over several nanoseconds. This technique was used to analyze millimeter‐sized chondrules and calcium‐aluminum‐rich inclusions on four carbonaceous chondrite samples provided by the Royal Ontario Museum: Murchison (CM2), Allende (CV3), NWA 11554 (CV3), and NWA 12796 (CK3). The LIF 2‐D maps, point spectra, and time‐resolved fluorescence data and mineral identifications using LIF were compared to that of well‐known techniques such as Raman spectroscopy and SEM/EDS.