Data Set Overview
  =================
    This data set describes the data of the high time resolution counting
    rate from the D1 detector in the Cosmic Ray System (CRS) electron
    telescope (TET) on Voyager 2 during the Neptune encounter.
    The D1 detector nominally responds to electrons with kinetic energies
    above approximately 1 MeV (see detector description for details).

  Parameters
  ==========

      Sampling parameter name             : time
      Sampling parameter resolution       : 6.0 seconds
      Minimum sampling parameter          : n/a
      Maximum sampling parameter          : n/a
      Sampling parameter interval         : 6.0 seconds
      Minimum available sampling interval : 6.0 seconds
      Data set parameter name             : D1 rate
      Noise level                         : 0.000 counts/second
      Data set parameter unit             : counts/second

      The D1 rate is the counting rate from the D1 detector
      of the Cosmic Ray System (CRS) electron telescope (TET).
      When the rate is above background it is approximately
      proportional to the omnidirectional flux of electrons
      with kinetic energy greater than ~1 MeV.
      To obtain an accurate flux the D1 calibration tables
      should be used (see below).  When the rate is near
      background, the background rate should be subtracted.
      The background rate is due to gamma rays generated in
      the spacecraft RTG and to penetrating cosmic rays.  It
      varies slightly with time on the time scale of months,
      but is generally near 25 counts per second.  When the
      rate is near saturation, corrections for discriminator
      deadtime should be made.  The discriminator deadtime is
      approximately 20 micro-seconds (it varies slightly with
      the electron energy spectrum), so that the saturation
      level is approximately 50,000 counts per second.
      When the correction is near a factor of two or less
      a reliable corrected rate can be obtained from the formula
      {corrected rate} = {uncorrected rate}/(1+deadtime*{uncorrected rate})
      When the deadtime correction is substantially larger than
      a factor of two, reliable corrections are not available.
      In this case, electron pileup and baseline shift may also
      be important, which may increase or decrease the expected
      rate.  The data points are 6 second averages taken
      once every 96 seconds.

      Table 1 below provides the D1 response function R(E,theta)
      which is a function of electron energy E in MeV (column at left)
      and angle theta in degrees from the TET axis (row at top).
      Each table entry is R in cm**2 for the corresponding E and theta.
      The D1 electron rate is related to the differential intensity
      j(E,alpha) in (cm**2 s sr MeV)**-1, where alpha is the electron
      pitch-angle, by integrating the product R*j over E and solid angle.
      Note that the angle between the TET axis and the local magnetic
      field direction is also required.  The D1 RATE is then obtained
      by adding the background rate and applying the inverse of the
      deadtime correction described above.  At energies above the
      maximum provided R can be approximated by the value at the
      highest provided energy.  At angles above the maximum provided R
      can be approximated by zero.

    -------------------------------------------------------------------
    Table 1. D1 response function
    -------------------------------------------------------------------
            |  11.    15.    23.    32.    41.    51.    61.
    -------------------------------------------------------------------
            |
      0.618 | 0.014  0.005  0.007  0.007  0.006  0.003  0.001
      0.801 | 0.151  0.134  0.103  0.087  0.038  0.016  0.008
      0.989 | 1.384  1.440  1.219  0.998  0.610  0.311  0.143
      1.179 | 2.233  2.402  2.095  1.796  1.255  0.689  0.380
      1.372 | 2.829  2.938  2.593  2.241  1.636  0.956  0.583
      1.567 | 3.212  3.283  2.936  2.536  1.940  1.167  0.724
      1.763 | 3.495  3.534  3.206  2.772  2.161  1.356  0.860
      1.959 | 3.708  3.705  3.404  2.964  2.357  1.495  0.969
      2.157 | 3.620  3.790  3.452  3.053  2.427  1.602  1.049
      2.355 | 3.995  3.948  3.576  3.231  2.617  1.758  1.155
      2.553 | 4.096  4.091  3.735  3.395  2.735  1.875  1.263
      2.752 | 4.154  4.098  3.808  3.426  2.792  1.927  1.298
      2.951 | 4.043  4.054  3.727  3.371  2.819  1.951  1.339
      3.150 | 3.946  4.029  3.700  3.335  2.648  1.956  1.358
      3.350 | 3.876  4.194  3.611  3.573  2.863  1.927  1.290

    -------------------------------------------------------------------
    Table 1. D1 response function (continued)
    -------------------------------------------------------------------
            |  70.    80.    90.   100.
    -------------------------------------------------------------------
      0.618 | 0.002  0.001  0.000  0.000
      0.801 | 0.010  0.007  0.004  0.001
      0.989 | 0.163  0.095  0.047  0.018
      1.179 | 0.386  0.217  0.113  0.056
      1.372 | 0.526  0.301  0.163  0.087
      1.567 | 0.617  0.366  0.201  0.117
      1.763 | 0.679  0.413  0.241  0.146
      1.959 | 0.730  0.461  0.270  0.179
      2.157 | 0.760  0.484  0.296  0.207
      2.355 | 0.809  0.518  0.329  0.242
      2.553 | 0.836  0.551  0.363  0.292
      2.752 | 0.856  0.564  0.392  0.319
      2.951 | 0.845  0.548  0.401  0.348
      3.150 | 0.837  0.559  0.400  0.374
      3.350 | 0.792  0.486  0.440  0.375


  Processing
  ==========
    The ENCYCLOPEDIA GENERATOR program was run by Nand Lal at Goddard
    Space Flight Center to read the EDR tape, check for error
    conditions, and reformat the data to generate a CRS encyclopedia
    tape. The resulting tape was sent to CalTech for subsequent data
    analysis.

    The VCRUSH program was run at CalTech to select data of interest
    from CRS encyclopedia tapes. In the case of counting rate data,
    no further analysis was done to produce the data in the PDS
    data sets.

    Note: Neither the ENCYCLOPEDIA GENERATOR or VCRUSH software are
    available for public use.

Confidence Level Overview
  =========================
    Each data point represents a six-second accumulation,
    so that the statistical uncertainty is obtained according
    to Poisson statistics by taking the square root of one sixth
    of the counting rate. However, larger uncertainties are
    associated with the conversion from counting rate to flux.


  Data Coverage and Quality
  =========================
    The following table contains hourly summaries of the percentage of
    the data available, data quality, and contamination codes. A data
    quality id of -1 indicates that no attempt has been made to specify
    a data quality for this time range. A contamination code of -1
    signifies that no evaluation of possible contamination has been
    made.

    -------------------------------------------------------------------
    Table 2. Hourly Data Coverage and Quality Summaries
    -------------------------------------------------------------------
    Start Time            Mode  Percent  Quality  Contam  NumGood
    -------------------------------------------------------------------
    1989-Aug-25 05:21:02  D1     19.833    -1       -1     357