PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM INSTRUMENT_HOST_NAME = "2001 MARS ODYSSEY" INSTRUMENT_NAME = "GAMMA RAY SPECTROMETER" TARGET_NAME = MARS OBJECT = TEXT PUBLICATION_DATE = 2003-07-31 NOTE = "Introduction to Odyssey GRS DND Data" END_OBJECT = TEXT END 2001 MARS ODYSSEY GAMMA RAY SPECTROMETER DERIVED NEUTRON DATA Introduction ------------ The Odyssey Gamma Ray Spectrometer (GRS) Derived Neutron Data (DND) products are a time series collection of measurements from the NS sub-system of the Mars Odyssey Gamma Ray Spectrometer. The DND are generated by processing GRS neutron spectrometer EDRs (Experiment Data Records, or raw data). These data are intermediate products that must be derived from the raw data before a set of calculations can be run that will result in thermal, epithermal, and fast neutron fluxes. Information about the DND product can be found in the GRS IDR (Intermediate Data Product) Software Interface Specification (SIS) in the DOCUMENT directory of this archive. File Formats ------------ The GRS DND data products are stored as binary files with detached ASCII-text PDS labels. Each file contains corrected spectra acquired over a 24-hour time period. Files are grouped into directories by Earth day. The file naming convention for GRS DND data files is "DND_" followed by a date in the format YYYYMMDD. An example file name is DND_20020321.DAT. Each data file is described by a PDS label in a separate file with the same name, extension ".LBL", in the same directory as the data file. The labels contain identification and observation parameters associated with the data files and definitions for the TIME_SERIES objects. The PDS labels include a pointer to a format file that contains column definitions (extension ".FMT"). The format file is found in the LABEL directory. Volume Contents --------------- The GRS DND archive volume includes the following files and directories. Root directory AAREADME.TXT - the file you are reading ERRATA.TXT - notes and errata, if any VOLDESC.CAT - volume description for the PDS catalog INDEX directory INDXINFO.TXT - description of contents of this directory INDEX.TAB - index of all products in the archive INDEX.LBL - PDS label that describes INDEX.TAB DOCUMENT directory DOCINFO.TXT - description of contents of this directory GRS_NS_PROCESSING.PDF - Description of processing applied to NS data GRS_NS_PROCESSING.LBL - PDS label for GRS_NS_PROCESSING.PDF GRS-IDR-SIS.PDF - Detailed data product description in PDF format GRS-IDR-SIS.LBL - PDS label for GRS-IDR-SIS.PDF TIME_CONVERSION_TABLES.PDF - Tables for converting Earth to Mars time TIME_CONVERSION_TABLES.LBL - PDS label for TIME_CONVERSION_TABLES.PDF CATALOG directory CATINFO.TXT - description of contents of this directory *.CAT - descriptions of dataset, instrument, spacecraft, mission, and personnel for the PDS catalog LABEL directory LABINFO.TXT - description of contents of this directory DERIV_NEUTRON_DATA_COLS.FMT - format of columns in DND data file SOFTWARE directory GRS_CODE.ZIP - Library of Java source code for parsing data files GRS_CODE.LBL - PDS label for GRS_CODE.LBL GRS_CODE_DOC.ZIP - Documentation for source code library GRS_CODE_DOC.LBL - PDS label for GRS_CODE_DOC.LBL SOFTINFO.TXT - description of contents of this directory Data directories Data files are aggregated by day, with a separate subdirectory for each day, named according to the format YYYYMMDD. These subdirectories are in turn grouped into directories by year, with names in the format YYYY. Contacts -------- For questions concerning these data products and documentation, contact: PDS Geosciences Node Washington University Dept. of Earth and Planetary Sciences 1 Brookings Drive St. Louis, MO 63130 314-935-5493 WWW Site: http://pds-geosciences.wustl.edu/ Electronic mail address: geosci@wunder.wustl.edu