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VG2 NEP CRS RESAMPLED SUMMARY D1 RATE ELEC 96SEC V1.0 (PDS)

NSSDCA ID: PSFP-00608

Availability: Archived at NSSDC, accessible from elsewhere

Time span: 1989-08-24 to 1989-08-25

Description

This description was generated automatically using input from the Planetary Data System.

Data Set Overview ================= This data set describes the 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 : 96.0 seconds Minimum available sampling interval : 96.0 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.

These data are available on-line from the Planetary Data System (PDS) at:

https://pds-ppi.igpp.ucla.edu/data/VG2-N-CRS-4-SUMM-D1-96SEC-V1.0/

Alternate Names

  • VG2-N-CRS-4-SUMM-D1-96SEC-V1.0

Discipline

  • Planetary Science: Fields and Particles

Additional Information

Spacecraft

Experiments

Questions and comments about this data collection can be directed to: Dr. Edwin V. Bell, II

 

Personnel

NameRoleOriginal AffiliationE-mail
Prof. Edward C. Stone, Jr.Data ProviderCalifornia Institute of Technologyecs@srl.caltech.edu
Dr. Richard S. SelesnickGeneral ContactCalifornia Institute of Technologyrss@srl.caltech.edu
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