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Title: Application of distance correction to ChemCam laser-induced breakdown spectroscopy measurements

Laser-induced breakdown spectroscopy (LIBS) provides chemical information from atomic, ionic, and molecular emissions from which geochemical composition can be deciphered. Analysis of LIBS spectra in cases where targets are observed at different distances, as is the case for the ChemCam instrument on the Mars rover Curiosity, which performs analyses at distances between 2 and 7.4 m is not a simple task. Previously, we showed that spectral distance correction based on a proxy spectroscopic standard created from first-shot dust observations on Mars targets ameliorates the distance bias in multivariate-based elemental-composition predictions of laboratory data. In this work, we correct an expanded set of neutral and ionic spectral emissions for distance bias in the ChemCam data set. By using and testing different selection criteria to generate multiple proxy standards, we find a correction that minimizes the difference in spectral intensity measured at two different distances and increases spectral reproducibility. When the quantitative performance of distance correction is assessed, there is improvement for SiO 2, Al 2O 3, CaO, FeOT, Na 2O, K 2O, that is, for most of the major rock forming elements, and for the total major-element weight percent predicted. But, for MgO the method does not provide improvements while formore » TiO 2, it yields inconsistent results. Additionally, we observed that many emission lines do not behave consistently with distance, evidenced from laboratory analogue measurements and ChemCam data. This limits the effectiveness of the method.« less
Authors:
 [1] ;  [1] ;  [2] ; ORCiD logo [2] ;  [3] ; ORCiD logo [2] ;  [4] ;  [4] ; ORCiD logo [2] ;  [3] ;  [3] ;  [3] ;  [3] ;  [5] ;  [5] ;  [6] ;  [7]
  1. Delaware State Univ., Dover, DE (United States). Optical Science Center for Applied Research
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  3. Univ. of Paul Sabatier, Toulous (France). Inst. for Research in Astrophysics and Planetology (IRAP)
  4. Planetary Science Inst., Flagstaff, AZ (United States)
  5. Mount Holyoke College, South Hadley, MA (United States). Dept. of Astronomy
  6. Univ. of Grenoble (France). Inst. of Earth Sciences
  7. French National Center for Scientific Research (CNRS), Paris (France)
Publication Date:
Report Number(s):
LA-UR-17-26884
Journal ID: ISSN 0584-8547
Grant/Contract Number:
AC52-06NA25396; NNX10AN63H; NNX09AU90A
Type:
Accepted Manuscript
Journal Name:
Spectrochimica Acta. Part B, Atomic Spectroscopy
Additional Journal Information:
Journal Volume: 120; Journal Issue: C; Journal ID: ISSN 0584-8547
Publisher:
Elsevier
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
National Aeronautics and Space Administration (NASA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 36 MATERIALS SCIENCE; Stand-off laser-induced breakdown spectroscopy (ST-LIBS); Mars; Dust; Calibration; Geological analysis
OSTI Identifier:
1394988