File: P11GTT_11_FMT.txt                     Version: NSSDC 11/15/2001 JFC
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Data Format for Hourly Average Parameters from Pioneer 11 GTT Experiment

Principal Investigator: Prof. James A. Van Allen
                        Dept. of Physics and Astronomy
                        University of Iowa
                        Iowa City, IA

Dataset Description:

The Pioneer 11 Geiger-Mueller Tube (GTT) experiment measures cosmic ray  
and magnetospheric energetic electron and proton intensities in the energy 
range of 0.06 to 10**2 MeV. This data set consists of hourly averages of 
selected interplanetary counting rates computed by NSSDC staff from 15-min. 
averaged data in the full binary data set 73-019A-11E in the NSSDC tape 
archive and described in the SFDU document P11GTT_15M.sfdu. 

Date Coverage: 1973-04-06 to 1991-06-06

Data Parameters:

NYY NDOY MHR MMN NSEC NTSAMP RATGG RATA RATB RATC RATD RSCS HLATSC

Data Parameter Definition:

NYY - YEAR (SCET)
NDOY- DAY OF YEAR (SCET)
MHR - HOUR
MMN - MINUTE
NSEC - SECONDS
NTSAMP - DATA SAMPLES NORMALIZED TO 2048 BPS TELEMETRY RATE
RATGG- G+G COUNTING RATE (ELECTRONS > 0.06 MeV, PROTONS > 25 MEV)
RATA- A CHANNEL COUNTING RATE (ELECTRONS > 5 MEV, PROTONS > 30 MEV)
RATB- B CHANNEL COUNTING RATE (ELECTRONS > 0.55 MEV, PROTONS > 6.6 MEV)
RATC- C CHANNEL COUNTING RATE (ELECTRONS > 21 MEV, PROTONS > 80 MEV)
RATD- D CHANNEL COUNTING RATE (ELECTRONS > 31 MEV, PROTONS > 80 MEV)
RSCS- SUN-SPACECRAFT DISTANCE (AU)
HLATSC- HELIOGRAPHIC LATITUDE OF SPACECRAFT (DEGREES)

Due to low energy thresholds in some detectors on Pioneer 11 the GTT
data fields may overflow during solar energetic particle events. In this
case each affected field is filled with astericks (*). Data which completely
fill the allowed fields are otherwise okay but need to read with fixed
format read statements.

FORTRAN Statement for Data File Format:

      WRITE(IPRT,1234) NYY,NDOY,MHR,MMN,NSEC,NTSAMP,RATGG,RATA,RATB,
     *   RATC,RATD,RSCS,HLATSC
1234  FORMAT(1X,I2,1X,I3,3(1X,I2),1X,I5,1X,3F8.3,2F7.3,2(1X,F8.4))

File Structure:

The COHO data files are divided into six-month blocks. For example, 
P11GT73A.asc includes data for Jan.-Jun. of 1973 while P11GT73B.asc has
data for Jul.-Dec. of 1973.

Related Information and Data:

Further details on the spacecraft, experiment, data sets at NSSDC, and related
WWW sites can be found on the Pioneer 10/11 flight project page under

http://nssdc.gsfc.nasa.gov/space/

Hour averages of the interplanetary solar wind data from, and hourly heliocentric
coordinates of, Pioneer 10/11 and other interplanetary spacecraft may be also
be accessed and plotted on-line through the COHOWeb service based at the same
WWW site as above.

Acknowledgement:

Use of these data in publications should be accompanied at minimum by
acknowledgements of the National Space Science Data Center and the responsible
Principal Investigator defined in the experiment documentation provided here.