Data Set Overview
  =================
    This data set is used to study the mineralogic
    composition of iron-bearing phases in Martian rocks and soils. For a
    Moessbauer experiment on any target, MIMOS II stores in memory for
    return to the Earth the following information: (1) a PHA spectrum
    for each of the 5 detectors; (2) five Moessbauer spectra
    (one reference and four sample spectra) for each of the 13
    temperature intervals for a total of 65 spectra; (3) reference and
    sample temperatures; and (4) engineering data (e.g., the error
    signal for the velocity transducer). The Moessbauer spectra are in
    counts per channel for 512 channels. In (2), the four sample
    Moessbauer spectra in each temperature interval can selected in a
    number of ways. For example, they can be the 14.4 keV spectrum from
    each of the four detectors or the sum of the 14.4 and 6.4 keV
    spectra for each of the four detectors. Alternatively, the four
    spectra can be 14.4 and 6.4 keV spectra, each summed over two
    detectors. The spectra can be analyzed individually or combined to
    produce higher quality spectra. Combining spectra from different
    temperature intervals will depend on how strongly the spectra depend
    on temperature.
 
 
  Processing
  ==========
    This SIS uses the Committee On Data Management And Computation
    (CODMAC) data level numbering system to describe the processing
    level of EDR data products. MB EDR data products are considered
    CODMAC Level 2 or Edited Data (equivalent to NASA level 0)
    products. The EDR data files are generated from Level 1 or
    Raw Data, which are the telemetry packets within the project
    specific Standard Formatted Data Unit (SFDU) record.
 
    The MB EDR data products will be generated by the MIPL (Multimission
    Image Processing Laboratory) at JPL under the OPGS using the
    telemetry processing software, mertelemproc. The EDR data products
    will be raw uncalibrated data reconstructed from telemetry data
    products generated by the SSW team and formatted according to this
    EDR SIS. Meta-data acquired from the telemetry data headers will be
    used to populate the PDS label. There will not be multiple versions
    of an MB EDR. If telemetry data is missing partial data sets will be
    created and the missing data will be filled with zeroes. The data
    will be reprocessed after all data are received and the original
    version will be overwritten.
 
 
  Data
  ====
    A MB EDR data product consists of five contiguous blocks of binary
    data or a single block and a detached ASCII PDS label. Each data
    block is 32 Kbytes long for a total size of 160 Kbytes or 32 Kbytes.
    The five data blocks are a copy of the instrument's memory buffer.
    The EDR file contains Moessbauer spectra for a given target measured
    in thirteen temperature windows, along with temperature data, an
    energy spectrum, a drive error signal spectrum, copies of the
    instrument parameter block and logbook. In addition, the file
    contains ten compressed Moessbauer spectra stored in the EEPROM as
    backup in case the instrument loses power. The backup spectra are
    updated during data acquisition, approximately every 6 minutes.
 
    Data from the instrument's SRAM occupy the first four blocks in the
    Moessbauer EDR data product. It contains three copies of the
    instrument parameter block, a drive error signal, temperature data,
 an energy spectrum, and Mossbauer spectra from 13 temperature
    windows.
 
    Each copy of the instrument parameter block in the SRAM is 512 bytes
    long. The SRAM has three copies of the parameter block for a total
    of 1536 bytes. The drive error signal, which monitors the operation
    of the MB drive unit, has 512 channels with two bytes per channel.
    The drive error signal values are stored in LSB first order. The MB
    EDR file contains temperature data recorded by three sensors: one on
    the electronics board, one on the sensor head, and one on the
    reference sensor. Each temperature value is scaled and stored as a
    two byte integer in MSB first order. The file contains 256
    temperature records. Within each record, the order of values is
    board sensor, sample sensor, and reference sensor. The following
    equations contain the conversion of the scaled temperatures into
    Kelvin:
 
    Board sensor = 273.2 + 25 + (scaled value * 1.638*2500/4096+608)/2
    Sample sensor = (scaled value)/10
    Reference sensor = (scaled value)/10
 
    The energy spectrum, which monitors the operation of the detectors,
    contains 256 channels of data for each of 5 detectors. Each value is
    a three byte integer stored in LSB first order. The data are
    aggregated so that data for the first detector are followed by data
    for the second detector and so on.
 
    Moessbauer data collected during a measurement are divided into
    temperature windows defined by a selectable lookup table. Each
    Moessbauer temperature window consists of five spectra (one for each
    detector). One spectrum contains 512 channels with three bytes per
    channel stored in LSB first order. The first channel of each
    spectrum gives the measurement lifetime, where lifetime is the
    number of cycles that the MB drive unit has executed during the
    measurement. The collection of MB spectra can be described as a
    three-dimensional array with axes of temperature window, detector,
    and channel, with the channel axis varying the fastest.
 
    The fifth data block of the MB EDR data file contains a copy of the
    instrument FRAM and EEPROM memory, along with copies of one
    Moessbauer temperature window, the drive error signal, instrument
    parameter block, and temperature data. The FRAM consists of three
    copies of the instrument parameter block and the instrument logbook.
    The logbook has 256 records with eight bytes in each record. The
    structure of the logbook is described in the Moessbauer Spectrometer
    Information Interface Control Document. The EEPROM contains ten
    compressed MB spectra. The data are compressed by combining data
    from several temperature windows or from several detectors. Each
    compressed MB spectrum has 512 channels with three bytes per channel
    stored in LSB first order.
 
 
  Software
  ========
    A reader program, called mb2asc, will be available for a variety of
    computer platforms to convert the MB EDR binary format data into
    ASCII format. This reader will be archived with the EDR data
    products. The ASCII format data can be imported into spread sheet
    and plotting programs.
 
 
  Media/Format
  ============
    The data set will initially be delivered and kept online. Upon
    Mission completion, the Moessbauer EDRs will be delivered to PDS on
    DVD as part of the complete MER EDR data set.

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