Data Set Overview
      =================

      Data Set Description
      --------------------
      This browse data consists of resampled data from the Low
      Energy Charged Particle (LECP) experiment on Voyager 2 while
      the spacecraft was in the vicinity of Saturn. This instrument
      measures the intensities of in-situ charged particles (>26 keV
      electrons and >30 keV ions) with various levels of
      discrimination based on energy, mass species, and angular
      arrival direction. A subset of almost 100 LECP channels are
      included with this data set. The LECP data are globally
      calibrated to the extent possible (see below) and they are
      time averaged to about 15 minute time intervals with the exact
      beginning and ending times for those intervals matching the
      LECP instrumental cycle periods (the angular scanning
      periods). The LECP instrument has a rotating head for
      obtaining angular anisotropy measurements of the medium energy
      charged particles that it measures. The cycle time for the
      rotation is variable, but during encounters it is always
      faster than 15 minutes. For this browse data set only scan
      average data is given (no angular information). The data is in
      the form of 'rate' data which has not been converted to the
      usual physical units. The reason is that such a conversion
      would depend on uncertain determinations such as the mass
      species of the particles and the level of background. Both
      mass species and background are generally determined from
      context during the study of particular regions. To convert
      'rate' to 'intensity' for a particular channel one performs
      the following tasks: 1) decide on the level of background
      contamination and subtract that off the given rate level.
      Background is to be determined from context and from making
      use of sector 8 rates (sector 8 has a 2 mm Al shield covering
      it). 2) Divide the background corrected rate by the channel
      geometric factor and by the energy bandpass of the channel.
      The geometric factor is found in entry
      'channel_geometric_factor' as associated with each channel
      'channel_id'. To determine the energy bandpass, one must judge
      the mass species of the of the detected particles (for ions
      but not for electrons). The energy band passes are given in
      entries 'minimum_instrument_parameter' and
      'maximum_instrument_parameter' in table 'FPLECPENERGY', and
      are given in the form 'energy/nucleon'. For channels that
      begin their names with the designations 'ch' these bandpasses
      can be used on mass species that are accepted into that
      channel (see entries 'MINIMUM_INSTRUMENT_PARAMETER' and
      'MAXIMUM_INSTRUMENT_PARAMETER' in table 'FPLECPCHANZ', which
      give the minimum and maximum 'Z' value accepted -- these
      entries are blank for electron channels). For other channels
      the given bandpass refers only to the lowest 'Z' value
      accepted. The bandpasses for other 'Z' values are not all
      known, but some are given in the literature (e.g.
      [KRIMIGISETAL1979A]). The final product of these instructions
      will be the particle intensity with the units:
      counts/(cm^2 str sec keV).

      Processing Level Id            : 4
      Software Flag                  : Y
      Processing Start Time          : 1988-08-01

      Parameters
      ==========

      Electron Rate
      -------------
      Sampling Parameter Name        : TIME
      Data Set Parameter Name        : ELECTRON RATE
      Sampling Parameter Resolution  : 15.000000
      Sampling Parameter Interval    : 15.000000
      Data Set Parameter Unit        : COUNTS/SECOND
      Noise Level                    : 0.000000
      Sampling Parameter Unit        : MINUTE

      A measured parameter equaling the number of electrons hitting
      a particle detector per specified accumulation interval. The
      counted electrons may or may not be discriminated as to their
      energies (e.g. greater than E1, or between E1 and E2).

      Ion Rate
      --------
      Sampling Parameter Name        : TIME
      Data Set Parameter Name        : ION RATE
      Sampling Parameter Resolution  : 15.000000
      Sampling Parameter Interval    : 15.000000
      Data Set Parameter Unit        : COUNTS/SECOND
      Noise Level                    : 0.000000
      Sampling Parameter Unit        : MINUTE

      A measured parameter equaling the number of ions striking a
      particle detector per specified accumulation interval. The
      counted ions may or may not be discriminated as to their
      energies (e.g. energy/nucleon or energy/charge between E1 and
      E2 or greater than E1) and/or as to their ion composition
      (atomic number Z or mass number greater than Z1 or M1, or
      between Z1 and z2 or M1 and M2).

      Source Instrument Parameters
      ============================
      Instrument Host ID              : VG2
      Data Set Parameter Name         : ION RATE
      Instrument Parameter Name       : ION RATE
      Important Instrument Parameters : 1

      Instrument Host ID              : VG2
      Data Set Parameter Name         : ELECTRON RATE
      Instrument Parameter Name       : ELECTRON RATE
      Important Instrument Parameters : 1

      Processing
      ==========

      Processing History
      ------------------
      Source Data Set ID          : VG2-S-LECP-2-
      Software                    : PFAT:VGER
      Product Data Set ID         : VG2-S-LECP-4-BR-15MIN


      Software 'PFAT:VGER'
      --------------------
      Software Name               : PFAT:VGER
      Software Type               : PIN
      Software Release Date       : N/A
      Node ID                     : N/A
      Cognizant Engineer          : N/A
      Software Access Description : N/A

      Data Coverage
      =============
      Filename Records Start                     Stop
      ----------------------------------------------------------------------
      Volume ID: VG_1601
      AVERAGE.TAB   668  1981-08-24T00:07:29.560   1981-08-30T23:52:30.430

      Missing Data Flag
      =================
      Any data column whose value is -9.9e+10 is a missing data
      value.

Confidence Level Overview
      =========================
      At all times during this planetary encounter there exist data
      in this data set that can be rated with the highest confidence
      level. However, some of the channels of data are contaminated
      by various kinds and various levels of contaminations. It is
      therefore imperative, in using this data set, that the
      contamination tables within the catalog be examined. Also, not
      all kinds of contamination have been fully documented. When in
      doubt the data supplier must be contacted.

      Some channels are subject to serious contaminations, and many
      of these contaminations cannot be removed except with a region-
      by-region analysis, which has not been done for this data.
      Thus, to use this data it is absolutely vital that the
      contamination types ('CONTAMINATION_ID' , 'CONTAMINATION_DESC')
      and the levels of contamination ('DATA_QUALITY_ID'
      corresponding to the definitions 'DATA_QUALITY_DESC') be
      carefully examined for all regions of study. A dead time
      correction procedure has been applied in an attempt to correct
      the linear effects of detector overdrive (pulse-pileup). This
      procedure does not fix severely overdriven detectors. A
      procedure is available for correcting Voyager 2 LECP electron
      contamination of low energy ion channels, but its
      effectiveness has been evaluated only for the Uranus data set.
      Thus, corrections have been applied only to the Uranus data
      set.