Paper AS+BI+MC-WeM12
Global Analysis Peak Fitting for Imaging NEXAFS Data
Wednesday, November 12, 2014, 11:40 am, Room 316
| Session: |
Chemical Imaging in 2D and 3D |
| Presenter: |
Mark H. Van Benthem, Sandia National Laboratory |
| Authors: |
M.H. Van Benthem, Sandia National Laboratory
J.A. Ohlhausen, Sandia National Laboratory
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| Correspondent: |
Click to Email |
We will present a method of analyzing NEXAFS image data to extract chemical information from the complex elemental peak structure in the material under analysis. The method, known as global analysis, fits emission bands to peaks described by nonlinear functions using nonlinear and linear optimization techniques. It can fit multiple types of peaks simultaneously, such as those found in NEXAFS spectra: Gaussian, Lorentzian, Voigt, asymmetric Gaussian and Lorentzian, and step edge with decay. Typically, peak fitting of NEXAFS data is very complex and somewhat arbitrary. Our method takes advantage of the high dimensionality of the image space to yield peaks with potentially greater reliability than single spectrum fitting. The method also employs data compression with principal component analysis (PCA) to rapidly complete the analysis. A discussion of the algorithm along with several examples of its application will be presented. Sandia is a multiprogram laboratory operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000.