Analysis of COSIMA spectra: Bayesian approach
We describe the use of Bayesian analysis methods applied to time-of-flight secondary ion mass spectrometer (TOF-SIMS) spectra. The method is applied to the COmetary Secondary Ion Mass Analyzer (COSIMA) TOF-SIMS mass spectra where the analysis can be broken into subgroups of lines close to inte...
| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2015-06-01
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| Series: | Geoscientific Instrumentation, Methods and Data Systems |
| Online Access: | http://www.geosci-instrum-method-data-syst.net/4/139/2015/gi-4-139-2015.pdf |
| Summary: | We describe the use of Bayesian analysis methods applied to time-of-flight
secondary ion mass spectrometer (TOF-SIMS)
spectra. The method is applied to the COmetary Secondary Ion Mass Analyzer (COSIMA) TOF-SIMS mass spectra
where the analysis can be broken into subgroups of lines close to
integer mass values. The effects of the instrumental dead time are discussed
in a new way. The method finds the joint probability density functions of
measured line parameters (number of lines, and their widths, peak
amplitudes, integrated amplitudes and positions). In the case of two or
more lines, these distributions can take complex forms. The derived
line parameters can be used to further calibrate the mass scaling
of TOF-SIMS and to feed the results into other analysis methods such
as multivariate analyses of spectra. We intend to use the method,
first as a comprehensive tool to perform quantitative
analysis of spectra, and second as a fast tool for studying
interesting targets for obtaining additional TOF-SIMS measurements
of the sample, a property unique to COSIMA. Finally, we point out
that the Bayesian method can be thought of as a means to solve inverse
problems but with forward calculations, only with no
iterative corrections or other manipulation of the observed data. |
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| ISSN: | 2193-0856 2193-0864 |