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High-Energy Cosmic X-Ray Spectra

NSSDCA ID: 1974-077A-05

Mission Name: Ariel 5
Principal Investigator:Prof. Harry Elliot


This experiment was designed to extend the spectral information on selected X-ray sources in the energy region above 20 keV. The detector was an 8 sq cm x 4 cm csi (na) scintillator actively collimated to provide 8 deg fwhm. Measurements were possible up to 2 MeV, although the efficiency of the detector fell steeply at this energy. The detector axis was inclined a few deg with respect to the satellite spin axis so that it coned as the satellite spun. The counting rate resulting from a point source a few deg from the spin axis was thus modulated with the spin period. This modulation was detected by dividing the spin cycle into four sectors and analyzing the different counting rates in each. In this way, the source intensity could be determined from the amplitude of the modulation. For pulsar observations, a large energy window at the lower end of the detector range was used. The observations in this energy region were analyzed for a pulsar periodicity in a special system that was part of the spacecraft handling electronics.

Alternate Names

  • Ariel5/High-EnergyCosmicX-RaySpectra
  • Pointed High Energy Experiment

Funding Agency

  • Unknown (United Kingdom)


    Additional Information

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



    NameRoleOriginal AffiliationE-mail
    Dr. A. R. EngelOther InvestigatorImperial
    Dr. John J. QuenbyOther InvestigatorImperial
    Prof. Harry ElliotPrincipal InvestigatorImperial College
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