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    • Keywords


      Geomagnetic Latitude; Equatorial Latitude; Atmospheric Depth; Latitude Variation; Cosmic Origin

    • Abstract


      The results of the first low energy gamma-ray (0.2 to 1 MeV) measurements at equatorial latitudes conducted by two-balloon flights over Hyderabad, India (7.6° N GM), are presented. The energy resolution of the detectors was sufficient to detect the γ-ray peak at 0.5 MeV due to the electron-positron annihilation. The flux of the 0.5 MeV photons was found to be 0.090 ± 0.012 photons/cm2 sec at an atmospheric depth of 10 gm cm2 and 0.048 ± 0.011 photons/cm2 sec at the top of the atmosphere. Comparison of our results with those obtained at higher latitudes, show the existence of a considerable latitude variation of the 0.5 MeV flux, about a factor of 4 between 55° and 7° latitudes at an altitude of 10 gm/cm2.

    • Author Affiliations


      A S Prakasarao1 V S Iyengar1 2 U R Rao1

      1. Physical Research Laboratory, Ahmedabad, India
      2. Tata Institute of Fundamental Research, Bombay, India
    • Dates


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