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Title: Improved accuracy in quantitative laser-induced breakdown spectroscopy using sub-models

We report that accurate quantitative analysis of diverse geologic materials is one of the primary challenges faced by the Laser-Induced Breakdown Spectroscopy (LIBS)-based ChemCam instrument on the Mars Science Laboratory (MSL) rover. The SuperCam instrument on the Mars 2020 rover, as well as other LIBS instruments developed for geochemical analysis on Earth or other planets, will face the same challenge. Consequently, part of the ChemCam science team has focused on the development of improved multivariate analysis calibrations methods. Developing a single regression model capable of accurately determining the composition of very different target materials is difficult because the response of an element’s emission lines in LIBS spectra can vary with the concentration of other elements. We demonstrate a conceptually simple “submodel” method for improving the accuracy of quantitative LIBS analysis of diverse target materials. The method is based on training several regression models on sets of targets with limited composition ranges and then “blending” these “sub-models” into a single final result. Tests of the sub-model method show improvement in test set root mean squared error of prediction (RMSEP) for almost all cases. Lastly, the sub-model method, using partial least squares regression (PLS), is being used as part of the currentmore » ChemCam quantitative calibration, but the sub-model method is applicable to any multivariate regression method and may yield similar improvements.« less
Authors:
ORCiD logo [1] ;  [2] ; ORCiD logo [3] ;  [2] ;  [4] ;  [5] ;  [6] ;  [7]
  1. U.S.Geological Survey Astrogeology Science Center, Flagstaff, AZ (United States)
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  3. Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Univ. of Copenhagen, Copenhagen (Denmark)
  4. State Univ. of New York at Stony Brook (SUNY), Stony Brook, NY (United States)
  5. NASA Johnson Space Center, Houston, TX (United States)
  6. California Inst. of Technology (CalTech), Pasadena, CA (United States). Division of Geological and Planetary Sciences
  7. Mt. Holyoke College, South Hadley, MA (United States). Dept. of Astronomy
Publication Date:
Report Number(s):
LA-UR-16-28669
Journal ID: ISSN 0584-8547
Grant/Contract Number:
AC52-06NA25396
Type:
Accepted Manuscript
Journal Name:
Spectrochimica Acta. Part B, Atomic Spectroscopy
Additional Journal Information:
Journal Name: Spectrochimica Acta. Part B, Atomic Spectroscopy; Journal ID: ISSN 0584-8547
Publisher:
Elsevier
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE; National Aeronautic and Space Administration (NASA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; 47 OTHER INSTRUMENTATION; Planetary Sciences
OSTI Identifier:
1337117