PDS_VERSION_ID       = PDS3
LABEL_REVISION_NOTE  = "
  2000-09-14 SDU:Taylor   Initial version;
  2004-06-30 NAIF:Semenov Pre 2004 peer-review update;
  2005-04-05 NAIF:Semenov Post 2004 peer-review update
  "

RECORD_TYPE          = STREAM

OBJECT               = INSTRUMENT
  INSTRUMENT_HOST_ID = "SDU"
  INSTRUMENT_ID      = "DFMI"

  OBJECT             = INSTRUMENT_INFORMATION
    INSTRUMENT_NAME  = "DUST FLUX MONITOR INSTRUMENT"
    INSTRUMENT_TYPE  = "DUST IMPACT DETECTOR"
    INSTRUMENT_DESC  = "

      This description was assembled from various Stardust project 
      documents (with permission from the Stardust project) and  
      direct contributions from the instrument science lead, Dr.
      Anthony J. Tuzzolino.


      Instrument Overview
      ===================
      The Dust Flux Monitor Instrument (DFMI) is part of the STARDUST
      instrument payload. It provides data on the particle flux and
      mass distribution in the coma of the comet.


      Scientific Objectives
      =====================
      The prime goal of the DFMI was to measure the particle flux and
      mass distribution during passage through the coma of Comet Wild-2
      in 2004. This information is valuable for assessment of
      spacecraft risk and health, and also for interpretation of the
      laboratory analysis of dust captured by the Aerogel dust
      collectors and returned to Earth.

      A secondary science goal was to measure the particle flux and mass
      distribution during the ~7 year interplanetary portions of the
      mission, where, in addition to measurements of the background
      interplanetary dust over the radial range 0.98 AU to 2.7 AU,
      multiple opportunities exist for possible detection by the DFMI
      of interplanetary particles, meteor-stream particles, and
      interstellar dust. This part of the investigation was not achieved
      due to problems with the instrument's power supply.


      Calibration
      ===========
      A description of the calibration of the DFMI sensors is provided
      in the calibration report document provided with the DFMI data
      set(s).


      Operational Considerations
      ==========================
      A problem with the power supply detected during post-launch
      checkout precluded operation of the instrument for more than
      thirty minutes. Fear of complete failure of the instrument led to
      its use being restricted to about thirty minutes each at the
      Annefrank and Wild 2 encounters.


      Detectors
      =========
      The DFMI consists of two different dust detector systems --  a
      polyvinylidene fluoride (PVDF) DUST SENSOR UNIT (SU), which
      measures particles with mass < ~10^-4 g, and a DUAL ACOUSTIC
      SENSOR SYSTEM (DASS), which utilizes two quartz piezoelectric
      accelerometers mounted on the first two layers of the spacecraft
      Whipple dust shield to measure the flux of particles with mass >
      10^-4 g. The large Whipple shield structures provide the large
      effective sensitive area required for detection of the expected
      low flux of high-mass particles. At the encounter speed of 6.1
      km/s, the DFMI measurements will extend over the particle mass
      range of 8 decades, from 10^-11 to >10^-3 g. More detailed
      description of the detectors is provided in Tuzzolino et al,
      2003.


      Electronics
      ===========
      A detailed description of instrument electronics and internal
      data processing is provided in Tuzzolino et al, 2003.


      Location
      ========
      The DSU sensor is mounted on the first layer of the central
      Whipple shield, as is one of the DASS sensors. The second DASS
      sensor is mounted on the second layer of the central Whipple
      shield.


      Operational Modes
      =================
      During the Wild 2 encounter DFMI operated in ENCOUNTER mode. In
      this mode the instrument provides measurements at least once per
      second, and up to 10 times per second, depending on the dust
      particle flux. In this mode the counters are not reset upon
      readout, providing accurate cumulative particle fluencies.


      Subsystems
      ==========
      A detailed description of the DFMI subsystems is provided in
      Tuzzolino et al, 2003.


      Measured Parameters
      ===================
      The DFMI PDVF sensors measure differential and cumulative
      particle fluxes over the particle mass range 10^-11 to 10^-4 g
      and cumulative particle fluxes for masses > 10^-4 g. The acoustic
      sensors measure particle fluxes for particles having mass greater
      than 10^-4 g."

  END_OBJECT          = INSTRUMENT_INFORMATION

  OBJECT              = INSTRUMENT_REFERENCE_INFO
    REFERENCE_KEY_ID  = "TUZZOLINOETAL2003"
  END_OBJECT          = INSTRUMENT_REFERENCE_INFO

END_OBJECT            = INSTRUMENT

END