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Proceedings Paper

Laser-ablation optical-cavity isotopic spectrometer for Mars rovers
Author(s): Alexander A. Bol'shakov; Xianglei Mao; Christopher P. McKay; Richard E. Russo
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Paper Abstract

A concept of a compact device for analyzing key isotopic composition in surface materials without sample preparation is presented. This design is based on an advanced modification of Laser Induced Breakdown Spectroscopy (LIBS). First, we developed Laser Ablation Molecular Isotopic Spectrometry (LAMIS) that involves measuring isotope-resolved molecular emission, which exhibits significantly larger isotopic spectral shifts than those in atomic transitions. Second, we used laser ablation to vaporize the sample materials into a plume in which absorption spectra can be measured using a tunable diode laser. The intrinsically high spectral resolution of the diode lasers facilitates measurements of isotopic ratios. The absorption sensitivity can be boosted using cavity enhanced spectroscopy. Temporal behavior of species in a laser ablation plasma from solid samples with various isotopic composition was studied. Detection of key isotopes associated with signs of life (carbon, nitrogen, hydrogen) as well as strontium and boron in laser ablation plume was demonstrated; boron isotopes were quantified. Isotope-resolved spectra of many other molecular species were simulated. The experimental results demonstrate sensitivity to 86Sr, 87Sr, and 88Sr with spectrally resolved measurements for each of them. It is possible to measure strontium isotopes in rocks on Mars for radiogenic age determination. Requirements for spectral resolution of the optical measurement system can be significantly relaxed when the isotopic abundance ratio is determined using chemometric analysis of spectra.

Paper Details

Date Published: 25 May 2012
PDF: 7 pages
Proc. SPIE 8385, Sensors and Systems for Space Applications V, 83850C (25 May 2012); doi: 10.1117/12.919905
Show Author Affiliations
Alexander A. Bol'shakov, Applied Spectra, Inc. (United States)
Xianglei Mao, Lawrence Berkeley National Lab. (United States)
Christopher P. McKay, NASA Ames Research Ctr. (United States)
Richard E. Russo, Applied Spectra, Inc. (United States)
Lawrence Berkeley National Lab. (United States)


Published in SPIE Proceedings Vol. 8385:
Sensors and Systems for Space Applications V
Khanh D. Pham; Joseph L. Cox; Richard T. Howard; Henry Zmuda, Editor(s)

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