########## Overview ########### This bundle contains supplementary data for the publication listed in the "Publication Information" section. The data are described in the "File Description" section as well as by the respective .xml labels. The data included are derived spectra, oxide concentrations, and associated metadata from the Mars Exploration Rover (MER) Alpha Particle X-ray Spectrometers (APXS) on the Spirit and Opportunity rovers. The derived spectra, referred to as composites, are produced through the summation of energy-normalized individual raw spectra. The summation of spectra of similar characteristics yields spectra of better statistics than individual measurements alone. This improvement in statistics benefits spectral analyses of weaker spectral signals, such as trace elements that may be below quantification limits within individual spectra. Individual composite spectra are provided by the "mer_apxs_composites_spectra.csv" which also contains the unique composite number. This unique composite number is also referenced in other archived tables. The characteristics of each composite are noted in "mer_apxs_composites_metadata.csv" alongside the unique composite number. The raw APXS spectral data (i.e., EDRs) included in a composite are provided by the "mer_apxs_composites_edr.csv". This file lists unique raw spectra data identifiers (via the nine-digit SCLK within an EDR filename) included within each unique composite number. Note, individual raw spectra data files can contain up to 12 new spectra associated with the measurement. Not all "sub spectra" within a data file are used as some may be prone to poor spectral resolution (e.g., due to temperature) and thus were discarded to maintain the integrity of the composite. The oxide concentrations and precision errors for select composite spectra are provided in "mer_apxs_composites_oxides.csv". The characteristics of individual raw APXS spectral data are noted in "mer_apxs_comopsites_target_characteristics.csv" alongside the EDR filename. Thus, pivoting between data tables is done by: mer_apxs_comopsites_target_characteristics | EDR SCLK | mer_apxs_composites_edr | |--Unique Composite Number-------.-----------------------------. | | | mer_apxs_composites_metadata , mer_apxs_composites_spectra , mer_apxs_composites_oxides ### Publication Information ### Knight, A. L. (2024) Composite spectral library of MER APXS observations. PDS Geosciences Node. doi:10.17189/fmmx-db70 This bundle contains supporting information for the manuscript: "Trace element concentrations from the MER Alpha Particle X-ray Spectrometers: Implications for the geologic histories of Meridiani Planum and Gusev crater" Abigail L. Knight (1), Scott J. VanBommel (1, 2), Ralf Gellert (3), Jeff A. Berger (4), Jeffrey G. Catalano (1, 2), Juliane Gross (5, 6). Journal of Geophysical Research: Planets. (1) Department of Earth and Planetary Sciences, Washington University in St. Louis, St. Louis, Missouri 63130, USA. (2) McDonnell Center for the Space Sciences, Washington University in St. Louis, St. Louis, Missouri 63130, USA. (3) Department of Physics, University of Guelph, Guelph, Ontario, Canada. (4) Jacobs JETSII at NASA Johnson Space Center, Houston, Texas 77058, USA. (5) NASA Johnson Space Center, Houston, Texas 77058, USA. (6) Department of Earth and Planetary Sciences, Rutgers University, Piscataway, New Jersey 08901, USA. ###### File Description ####### -- mer_apxs_composites_metadata.csv -- This table lists the shared characteristics within a given composite. The unique composite number is given in the first column. The remaining columns capture metadata shared among the individual data products ingested into the composite. -- mer_apxs_composites_edr.csv -- This table lists all the EDRs (by column) integrated into a given composite. The unique composite number is given by the first column. EDR SCLK values noted in the following columns correspond to the nine-digit SCLK time within the EDR (raw product) filename. Blank cells are noted by -999999999 as not all composites contain the same number of ingested raw data products. -- mer_apxs_composites_spectra.csv -- This table provides the resulting spectrum from the integration of several energy-normalized individual spectra (i.e., per mer_apxs_composites_edr.csv) of shared characteristics (i.e., per mer_apxs_composites_metadata.csv). The first column corresponds to the unique composite number. The remaining 512 columns correspond to the channel 1 through 512 of the composite spectrum, increasing monotonically by 32 eV per channel from 0 eV at channel 0. Channel 1 corresponds to the spectrum livetime in seconds. Channel 512 corresponds to the overflow channel, representative of all detected photons above the energy of channel 511. -- mer_apxs_composites_target_characteristics.csv -- This table captures the metadata of individual raw spectra. The inclusion of a raw data product within a composite was determined based on the desired shared characteristics (i.e., mer_apxs_composites_edr.csv and mer_apxs_composites_metadata.csv). The contents of this table were provided in part by existing mission data archived on the PDS, including the following products: -urn:nasa:pds:mer1_apxs_raw:document:mer1_apxs_obs::1.0 -urn:nasa:pds:mer2_apxs_raw:document:mer2_apxs_obs::1.0 -urn:nasa:pds:mer_cs_target_list:data:mera_cs_activity_list::1.0 -urn:nasa:pds:mer_cs_target_list:data:merb_cs_activity_list::2.0 -urn:nasa:pds:mer_cs_target_list:data:mera_cs_target_list::1.0 -urn:nasa:pds:mer_cs_target_list:data:merb_cs_target_list::2.0 -- mer_apxs_composites_target_oxides.csv -- This table provides the oxide concentrations and precision errors for select MER APXS composite spectra. ###### Archive Structure ####### Each document and data product in this bundle is described by a PDS4 label in a separate file with the same name but with the extension XML. PDS4 labels are XML (eXtended Markup Language) files that conform to the PDS4 Information Model XML schema at https://pds.nasa.gov/pds4/schema/released/. They are best viewed in an XML-aware text editor, and may be used by software that can manipulate XML documents. See these sources for more information. - For information about PDS4, see https://pds.nasa.gov/pds4/about/.