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Galactic and Solar Cosmic Rays

NSSDCA ID: 1974-097A-08

Mission Name: Helios-A
Principal Investigator:Dr. James H. Trainor


The detector complement of this experiment (E7) consisted of three separate dE/dx vs E telescopes and a proportional counter for monitoring solar X rays in the range 2-8 keV. The high-energy telescope had a geometric factor of 0.22 sq cm-sr and measured electrons in three ranges between 2 and 8 MeV, and protons and alpha particles in three ranges between 20 and 56 MeV/n. Protons above 230 MeV were also measured. The first low-energy telescope (geometric factor was 0.155 sq cm-sr) measured protons and Z>1 particles in three ranges between 3 and 21 MeV/n. The second low-energy telescope (geometric factor was 0.015 sq cm-sr) measured protons in several ranges between 0.12 and 2.1 MeV, alpha particles in the ranges 0.6-2.1 and 6-21.2 MeV/n, and electrons in four ranges between 0.12 and 2 MeV. For a number of coincidence modes, counting-rate data sectored into eight 45-deg sectors were obtained. The data cycle time was dependent on the spacecraft telemetry rate (variable between 4096 and 8 bits/s) and format. Under optimum conditions, five events per second were pulse-height analyzed and the rate data cycle was of the order of 5 min. At the slowest combination of bit rate and format, a complete data cycle required about 2.5 h. See IEEE Trans. on Nuc. Sci., NS-22, p. 570, 1975, and Raumfahrtforschung, v. 19, n. 5, pp. 258-260, 1975, for further details.

Alternate Names

  • Helios-A/GalacticandSolarCosmicRays


  • Astronomy: Cosmic Ray
  • Space Physics: Heliospheric Studies

Additional Information

Questions and comments about this experiment can be directed to: Dr. H. Kent Hills



NameRoleOriginal AffiliationE-mail
Dr. Frank B. McDonaldOther InvestigatorUniversity of Maryland
Dr. Bonnard J. TeegardenOther InvestigatorNASA Goddard Space Flight
Dr. Kenneth G. McCrackenOther InvestigatorCommonwealth Scientific and Industrial Research Orqanisation
Dr. Edward C. RoelofOther InvestigatorApplied Physics
Dr. James H. TrainorPrincipal InvestigatorNASA Goddard Space Flight Center
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