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Solar X-Ray (2-8A) and Lyman-Alpha (1030-1350A) Radiation

NSSDCA ID: 1959-009A-02

Mission Name: Explorer 7
Principal Investigator:Dr. Herbert D. Friedman


The solar X-ray and Lyman-alpha radiation were measured by means of gas ionization chambers mounted on opposite sides of the upper portion of the double cone configuration of the Explorer 7 satellite. Intensities were monitored in order to obtain a long-term history of solar X-ray and Lyman-alpha fluxes and to correlate these with terrestrial atmospheric responses. The two X-ray detectors (2.5 cm deep) were filled with argon gas and had beryllium windows (.021 g/sq cm) resulting in a sensitivity to X rays in the 2 to 8-A range. The Lyman-alpha detectors (on the opposite side), which were circular ionization chambers (1.9 cm in diameter) filled with nitric oxide gas, had lithium fluoride windows. Their sensitivity was in the 1050 to 1350-A interval. The data, however, were impossible to interpret in terms of incident solar radiation due to both the saturation of detector circuits by Van Allen radiation (150 keV electrons) and electronic difficulties in the feedback amplifier.

Alternate Names

  • Explorer7/SolarX-Ray_2-8A_andLyman-Alpha_1030-1350A_Radiation


  • Solar Physics: X-Ray
  • Solar Physics: Ultraviolet

Additional Information

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NameRoleOriginal AffiliationE-mail
Dr. Herbert D. FriedmanPrincipal InvestigatorUS Naval Research Laboratory
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