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Heavy Primary Cosmic Rays

NSSDCA ID: 1959-009A-03

Mission Name: Explorer 7
Principal Investigator:Dr. Martin A. Pomerantz


This experiment was designed to measure the omnidirectional flux of heavy primary cosmic rays in the rigidity range 1 to 15.5 GV. Particles with atomic numbers Z>5, Z>8, and Z>15 were counted separately by an ionization chamber in which each incident particle yielded a pulse. Pulse amplitude was substantially independent of the energy of the incident particle but was proportional to the square of its Z value. Each of the three counting rates was determined every 15 s. The experiment performed as planned from launch until October 25, 1959. About 80% of the data acquired for the October 25, 1959, to May 31, 1960, period are useful, with most problems occurring in the lowest Z mode. Very little useful data were acquired after May 31, 1960.

Alternate Names

  • Explorer7/HeavyPrimaryCosmicRays


  • Space Physics: Heliospheric Studies

Additional Information

Questions and comments about this experiment can be directed to: Coordinated Request and User Support Office



NameRoleOriginal AffiliationE-mail
Dr. Martin A. PomerantzPrincipal InvestigatorBartol Research Foundation
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