October 1, 2017.
PIXL (Planetary Instrument for X-Ray Lithochemistry) is an instrument that will be aboard the MARS 2020 rover. This X-Ray Fluorescence Spectrometer will have the ability to identify the chemical elements of a soil or rock sample at a sub-millimeter scale with the help of a software program called PIQUANT which will be used for quantitative analysis of the elemental distribution of the rocks and soils. In order to quantify the elemental composition, ECF’s (element calibration factors) are created and derived from the measurements made from the PIXL instrument. Glass standards (BIR1, BCR2, BHVO2, NIST_610, XRF_U27, XRF_U34, BR_U38) are used in the calibration process to create a master ECF. To create the master ECF, inverse variance weighted mean is utilized to average out the ECFs from different standards while the error associated with the element is taken into account. This master ECF will correct the quantification values of the samples so that it may be used on “unknown” samples. We use actual rock powder samples such as GYP-B which is gypsum, as our “unknown” samples and use the master ECF made from the glass standards to quantify the elemental concentration of each samples. In our data, we notice that some elements are not present in any samples and as a result, we interpolate the sample’s ECF by noting trends in the data. All of this will be used in the exploration of the Mars surface.
NASA Jet Propulsion Laboratory (JPL)
The 2017 STEM Teacher and Researcher Program and this project have been made possible through support from Chevron (www.chevron.com), the National Marine Sanctuary Foundation (www.marinesanctuary.org), the California State University Office of the Chancellor, and California Polytechnic State University, in partnership with NASA Jet Propulsion Laboratory.