Data Set Information
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| DATA_SET_NAME |
VG2 URA LECP RESAMPLED SUMMARY SCAN AVERAGED 24SEC V1.0
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| DATA_SET_ID |
VG2-U-LECP-4-SUMM-SCAN-24SEC-V1.0
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| NSSDC_DATA_SET_ID |
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| DATA_SET_TERSE_DESCRIPTION |
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| DATA_SET_DESCRIPTION |
This data consists of resampled data from the Low EnergyCharged Particle (LECP) Experiment on the Voyager 2 Spacecraftfor the period when Voyager 2 was in the vicinity of the planetUranus. The period covered is 1986/day 24/0000 SCET to1986/day 27/0000 SCET. This data approximates a time seriesof charged particle fluxes from a selection of channels availablefrom the instrument. The word approximates is used becausethe angle scanning modes of the instrument complicates thenature 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 averagedfor those time periods when the instrument is scanning, and aretime averaged over an arbitrary period (24 seconds)for the periods when the detectors are stationary. The angleaveraged records represent periods of time equal to 96 or 384sec (see below). This kind of data presentation has been calledthe LECP Scan data. Another form that is also available isthe LECP Step data that gives the angle distributions sampledduring the scanning periods. Two scanning situations occurred during the time of thisdata. They are: 1) continuous 48 sec stepping (48 seconds foreach 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 specialUranus scan cyclic with the following sequence: 7, scan, scan,7, scan, scan, repeat; where the 7 represents a 10.4 minuteperiod when the instrument is fixed in sector 7, and where theword scan represents a period of scanning (6 sec steppingfor a total scan time of 48 sec). For this Uranus Scan datathe two adjacent scans within the Uranus scan cyclic have beenaveraged together into a single, 96 sec record. The recordsof the 48 sec stepping mode (Mode 1 above) are for 6.4 minutes.As stated in the first paragraph, the records for the periodsof 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 notinstantaneous, and that for a few minutes the state of thescanning is not regular. Not also that there were briefinterruptions to, and changes in time phase in, the Mode (2)scan cyclic during the transitions into and out of themovable block periods that bracketed the close approachposition (not shown above). Obviously these stepping mode changes, and the angle sampleswitching that occurs during stepping mode (2), gives the dataa 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 keVPlease note that 3 of the electron channels are derived from4 of the instrumental channels by taking differences betweenadjacent (in energy) channels. The channel data is given in units of intensity:counts/(cm^2.sec.str.keV). For the ions, it has been assumedthat they consist only of protons. Intensity is derived fromthe 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 protonvalues of these parameters were used in deriving the intensitiesfor this data set. To obtain the Intensities under the assumptionthat some other mass species dominates, one must convert backto count rate (CR) utilizing the proton parameters, and thenconvert to intensity using the parameters corresponding to themass species in question. The parameters can be found inTable 1 of Krimigis et al. (Journal of Geophysical Research,V. 86, page 8227, 1981). The corresponding parameters for electronscan 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 witheach channel (expressed as a percent) is the largest of thetwo quantities: (i) one standard deviation Poisson statisticalerror, and (ii) a percentage assigned by the data supplierbased on the amount of contamination correction that has beenperformed on each data channel. Also supplied with each record of this data set is thefraction of the data accumulations that correspond to eachof the 8 angle sectors. For example, during a sector 7 stowperiod, this number will be 1.0 for sector 7 and 0.0 for allof the other sectors. A sector 9 has also been definedcorresponding to those accumulations with no known sectorassignment. Additionally supplied for each data channel is a one bit codethat tells whether that channel had any accumulations atall associated with it (1 = yes; 0 = no). This code must beused to distinguish between accumulations that yielded no countsand situations where the channel simply had no accumulations(results in Intensity = 0.0).Processing Level Id : 4Software Flag : YProcessing Start Time : 1991-07-24Processing Stop Time : 1991-07-25Parameters==========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 assumedthat they consist only of protons. Intensity is derived fromthe 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. Theproton values of these parameters were used in deriving theintensities for this data set. To obtain the Intensitiesunder the assumption that some other mass species dominates,one must convert back to count rate (CR) utilizing the protonparameters, and then convert to intensity using theparameters 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 inMauk et al. (Journal of Geophysical Research, V. 92, page15283, 1987). Prior to the conversion to intensity, thecount 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 : TIMEData Set Parameter Name : PARTICLE FLUX INTENSITYSampling Parameter Resolution : 24.000000Sampling Parameter Interval : 24.000000Minimum Available Sampling Int : 6.000000Data Set Parameter Unit : COUNTS/(CM**2*SECOND*STERRADIAN*KEV)Sampling Parameter Unit : SECONDSource Instrument Parameters============================Instrument Host ID : VG2Data Set Parameter Name : PARTICLE FLUX INTENSITYInstrument Parameter Name : PARTICLE MULTIPLE PARAMETERSImportant Instrument Parameters : 1Processing==========Processing History------------------Source Data Set ID : N/ASoftware : UNK Product Data Set ID : VG2-U-LECP-4-SUMM-SCAN-24SEC-V1.0
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| DATA_SET_RELEASE_DATE |
1993-02-01T00:00:00.000Z
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| START_TIME |
1989-01-24T12:00:00.000Z
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| STOP_TIME |
1989-01-27T12:00:00.000Z
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| MISSION_NAME |
VOYAGER
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| MISSION_START_DATE |
1972-07-01T12:00:00.000Z
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| MISSION_STOP_DATE |
N/A (ongoing)
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| TARGET_NAME |
URANUS
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| TARGET_TYPE |
PLANET
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| INSTRUMENT_HOST_ID |
VG2
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| INSTRUMENT_NAME |
LOW ENERGY CHARGED PARTICLE
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| INSTRUMENT_ID |
LECP
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| INSTRUMENT_TYPE |
CHARGED PARTICLE ANALYZER
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| NODE_NAME |
planetary plasma interactions
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| ARCHIVE_STATUS |
ARCHIVED
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| CONFIDENCE_LEVEL_NOTE |
Confidence note for the PDS Uranus LECP Scan data. High quality data is available from the LECP instrumentthroughout the time period addressed with this data set.The data is subject to errors associated with Poissonstatistics and associated with various kinds and levels ofcontamination. The known contaminations are: i) penetratingbackground, ii) Solar UV contamination within the lowest energyion channel when the detector faces sunward, and iii) electroncontamination of the lower energy ion channels (the contaminatingelectrons are measured). Corrections have been made to the datain attempts to remove the effects of these contaminations. An error parameter is given for each particle intensityvalue given in the data set. This error is expressed as apercentage. This number is the larger of the followingitems: 1) the one standard deviation Poisson error, and 2) avalue assigned by the data supplier associated with the degreeof correction that was required with regard to the contaminationslisted above. Missing data is indicated with a binary flag associatedwith each energy channel. Each channel's flag will read 1if at least one instrumental accumulation occurred for thatchannel and for that record. The flag reads 0 for noaccumulations. This parameter must be utilized to distinguishbetween accumulations that yielded no counts, and the situationwhere there simply were no accumulations (the error parameterreads 100 for both cases).
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| CITATION_DESCRIPTION |
Mauk, B.H., VG2-U-LECP-4-SUMM-SCAN-24SEC-V1.0, VG2 URA LECP RESAMPLED SUMMARY SCAN AVERAGED 24SEC V1.0, NASA Planetary Data System, 1993.
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| ABSTRACT_TEXT |
This data consists of resampled datafrom the Low Energy Charged Particle (LECP) Experiment on the Voyager 2Spacecraft for the period when Voyager 2 was in the vicinity of the planetUranus.
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| PRODUCER_FULL_NAME |
DR. BARRY MAUK
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| SEARCH/ACCESS DATA |
Planetary Plasma Interactions Website
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