Normalization of the SAM Spectra Using PFTBA
Student: Raul Garcia-Sanchez
Howard University, Washington, D.C.
Degree Level: Ph. D.
Internship Site: NASA Goddard Space Flight Center, Greenbelt, Maryland
Mentor: Dr. Paul Mahaffy
Abstract: The organic contaminants library was developed as part of the contamination control plan for the Mars Science Laboratory rover mission. Work to normalize the data taken from Sample Analysis at Mars (SAM) to match standardized organic compound databases such as the National Institute of Standards and Technology (NIST) is needed in order to increase its availability to other potential users. To do this, we analyzed a standard fragmentation pattern, in this case Perfluorotributyl amine (PFTBA), using the SAM Gas Chromatography and Mass Spectroscopy GCMS settings that will be used for the actual mission and then calculated the ratio differences between the SAM PFTBA data and the NIST standard for PFTBA. This library is submitted as a New Technology Report, and will be readily available in the future. Carrying out a correction of the SAM spectral response, developing and providing an algorithm that makes these corrections to match with more standard libraries like NIST, will allow general users to use this library and correct SAM data for their work. The data is processed by correcting for instrumental calibration, and other specific instrumental behaviors. The processing is documented in a linked location related to the data directories. This works for a large number of the continuing satellite missions. The lower level data is primarily available from the mission operations groups. Although this work is intensive in terms of the GCMS Spectral library, the changes to the spreadsheets that contain entries supplementing the contaminants library should be minimal, and only needed when the normalization changes the spectra enough to change the chemical formula (in those cases the compound is properly identified by the library).
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