NASA Logo, National Aeronautics and Space Administration
NASA Space Science Data Coordinated Archive Header

VG2 URA LECP RESAMPLED SUMMARY SCAN AVERAGED 24SEC V1.0 (PDS)

NSSDCA ID: PSFP-00626

Availability: Archived at NSSDC, accessible from elsewhere

Time span: 1989-01-24 to 1989-01-27

Description

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

This data consists of resampled data from the Low Energy Charged Particle (LECP) Experiment on the Voyager 2 Spacecraft for the period when Voyager 2 was in the vicinity of the planet Uranus. The period covered is 1986/day 24/0000 SCET to 1986/day 27/0000 SCET. This data approximates a time series of charged particle fluxes from a selection of channels available from the instrument. The word approximates is used because the angle scanning modes of the instrument complicates the nature of the data. At times the instrument mechanically scans, and at times it is fixed to look at a specific direction. With the type of data given here, the fluxes are angle averaged for those time periods when the instrument is scanning, and are time averaged over an arbitrary period (24 seconds) for the periods when the detectors are stationary. The angle averaged records represent periods of time equal to 96 or 384 sec (see below). This kind of data presentation has been called the LECP Scan data. Another form that is also available is the LECP Step data that gives the angle distributions sampled during the scanning periods. Two scanning situations occurred during the time of this data. They are: 1) continuous 48 sec stepping (48 seconds for each of 8 look directions for a total of 6.4 minutes per scan; note that sector 8 is shielded with 2 mm Al), and 2) a special Uranus scan cyclic with the following sequence: 7, scan, scan, 7, scan, scan, repeat; where the 7 represents a 10.4 minute period when the instrument is fixed in sector 7, and where the word scan represents a period of scanning (6 sec stepping for a total scan time of 48 sec). For this Uranus Scan data the two adjacent scans within the Uranus scan cyclic have been averaged together into a single, 96 sec record. The records of the 48 sec stepping mode (Mode 1 above) are for 6.4 minutes. As stated in the first paragraph, the records for the periods of no stepping during the Uranus scan cyclic (mode 2 above) are for 24 sec periods. The schedule of mode changes is as follows: prior to day 24/0420: Mode (1) 24/0420 to 25/ 1357: Mode (2) after day 25/1357: Mode (1) Please note that the change-over between modes is not instantaneous, and that for a few minutes the state of the scanning is not regular. Not also that there were brief interruptions to, and changes in time phase in, the Mode (2) scan cyclic during the transitions into and out of the movable block periods that bracketed the close approach position (not shown above). Obviously these stepping mode changes, and the angle sample switching that occurs during stepping mode (2), gives the data a disjointed appearance. The LECP channels utilized with this data set are: EB01: electrons, 22 to 35 keV EB02: electrons, 35 to 61 keV EB03: electrons, 61 to 112 keV EB04: electrons, 112 to 183 keV EG06-EG07: electrons, 252 to 480 keV EG07-EG08: electrons, 480 to 853 keV EG08-EG09: electrons, 853 to 1200 keV PL01: ions, 28 to 43 keV PL02: ions, 43 to 80 keV PL03: ions, 80 to 137 keV PL04: ions, 137 to 215 keV PL05: ions, 215 to 540 keV PL06: ions, 540 to 990 keV PL07: ions, 990 to 2140 keV PL08: ions, 2140 to 3500 keV Please note that 3 of the electron channels are derived from 4 of the instrumental channels by taking differences between adjacent (in energy) channels. The channel data is given in units of intensity: counts/(cm^2.sec.str.keV). For the ions, it has been assumed that they consist only of protons. Intensity is derived from the raw count rates via the relation: I = CR/(eG.(E2-E1), where eG is geometric factor times detector efficiency, and (E2-E1) is the band pass of the channel in energy. The proton values of these parameters were used in deriving the intensities for this data set. To obtain the Intensities under the assumption that some other mass species dominates, one must convert back to count rate (CR) utilizing the proton parameters, and then convert to intensity using the parameters corresponding to the mass species in question. The parameters can be found in Table 1 of Krimigis et al. (Journal of Geophysical Research, V. 86, page 8227, 1981). The corresponding parameters for electrons can be found in Mauk et al. (Journal of Geophysical Research, V. 92, page 15283, 1987). Prior to the conversion to intensity, the count rates have been corrected for: (1) Background, (2) electron contamination of the lower energy ion channels, and (3) solar UV contamination of the lowest energy ion channel. The uncertainty parameters given with the data associated with each channel (expressed as a percent) is the largest of the two quantities: (i) one standard deviation Poisson statistical error, and (ii) a percentage assigned by the data supplier based on the amount of contamination correction that has been performed on each data channel. Also supplied with each record of this data set is the fraction of the data accumulations that correspond to each of the 8 angle sectors. For example, during a sector 7 stow period, this number will be 1.0 for sector 7 and 0.0 for all of the other sectors. A sector 9 has also been defined corresponding to those accumulations with no known sector assignment. Additionally supplied for each data channel is a one bit code that tells whether that channel had any accumulations at all associated with it (1 = yes; 0 = no). This code must be used to distinguish between accumulations that yielded no counts and situations where the channel simply had no accumulations (results in Intensity = 0.0). Processing Level Id : 4 Software Flag : Y Processing Start Time : 1991-07-24 Processing Stop Time : 1991-07-25 Parameters ========== Data Set Parameter 'PARTICLE FLUX INTENSITY' -------------------------------------------The channel data is given in units of intensity: counts/(cm^2.sec.str.keV). For the ions, it has been assumed that they consist only of protons. Intensity is derived from the raw count rates via the relation: I = CR/(eG.(E2-E1), where eG is geometric factor times detector efficiency, and (E2-E1) is the band pass of the channel in energy. The proton values of these parameters were used in deriving the intensities for this data set. To obtain the Intensities under the assumption that some other mass species dominates, one must convert back to count rate (CR) utilizing the proton parameters, and then convert to intensity using the parameters corresponding to the mass species in question. The parameters can be found in Table 1 of Krimigis et al. (Journal of Geophysical Research, V. 86, page 8227, 1981). The corresponding parameters for electrons can be found in Mauk et al. (Journal of Geophysical Research, V. 92, page 15283, 1987). Prior to the conversion to intensity, the count rates have been corrected for: (1) Background, (2) electron contamination of the lower energy ion channels, and (3) solar UV contamination of the lowest energy ion channel. Sampling Parameter Name : TIME Data Set Parameter Name : PARTICLE FLUX INTENSITY Sampling Parameter Resolution : 24.000000 Sampling Parameter Interval : 24.000000 Minimum Available Sampling Int : 6.000000 Data Set Parameter Unit : COUNTS/(CM**2*SECOND*STERRADIAN*KEV) Sampling Parameter Unit : SECOND Source Instrument Parameters ============================ Instrument Host ID : VG2 Data Set Parameter Name : PARTICLE FLUX INTENSITY Instrument Parameter Name : PARTICLE MULTIPLE PARAMETERS Important Instrument Parameters : 1 Processing ========== Processing History -----------------Source Data Set ID : N/A Software : UNK Product Data Set ID : VG2-U-LECP-4-SUMM-SCAN-24SEC-V1.0

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

https://pds-ppi.igpp.ucla.edu/data/VG2-U-LECP-4-SUMM-SCAN-24SEC-V1.0/

Alternate Names

  • VG2-U-LECP-4-SUMM-SCAN-24SEC-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
Dr. Stamatios M. KrimigisData ProviderApplied Physics Laboratorytom.krimigis@jhuapl.edu
Dr. Barry H. MaukGeneral ContactApplied Physics Laboratory
[USA.gov] NASA Logo - nasa.gov