https://spdf.gsfc.nasa.gov/pub/data/imp/imp5/00readme.txt
      

Directory "particles_apl" provides access to hourly resolution
energetic proton and alpha particle data from the
JHU/APL Solar Proton Monitoring Experiment (SPME)
on the IMP 5 spacecraft.  IMP 5 is
also known as IMP G and Explorer 41.  
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Related data and directories:
SPDF Data and Orbits Services <http://spdf.gsfc.nasa.gov/>
NSSDC Master Catalog <http://nssdc.gsfc.nasa.gov/nmc/sc-query.html>

NSSDC Contact: Natalia Papitashvili <Natalia.E.Papitashvili.1@gsfc.nasa.gov>,
 <request@mail630.gsfc.nasa.gov>

Please acknowledge NASA's National Space Science Data Center and
 Space Physics Data Facility for data usage.

Authorizing NASA Official: Dr. R.E. McGuire, Head, SPDF, NASA Goddard Space Flight Center
                        301-286-7794, e-mail:  Robert.E.McGuire@nasa.gov
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