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Proton-Alpha Telescope

NSSDCA ID: 1969-097A-02

Mission Name: Azur
Principal Investigator:Dr. Dieter K. Hovestadt


This experiment consisted of two identical proton-alpha particle telescopes, one oriented perpendicular and one oriented at 45 deg with respect to the local magnetic field vector. In the northern hemisphere, the 45-deg telescope pointed upwards. The telescopes were to detect protons and alpha particles in the earth's trapping region. The experiment was also used in conjunction with experiment 69-097A-04 (proton-electron detectors) to provide pitch angle distributions for protons above 20 MeV. Each telescope was composed of seven fully depleted silicon surface barrier detectors (D1 through D7) surrounded by a plastic anticoincidence scintillator (D8) and a heavy shielding (proton threshold energy of 75 MeV). The seven energy channels for which data were obtained are as follows: protons 1.5 to 2.7, 2.7 to 5.2, 5.2 to 10.4, 10.4 to 22, 22 to 49, and 49 to 104 MeV, and alpha particles 6 to 19 MeV. The telescopes had geometric factors of about 0.0580 sq cm sr. The acceptance cone of both telescopes was 31-deg full angle. The experiment performed normally throughout the mission.

Alternate Names

  • Azur/Proton-AlphaTelescope
  • Proton-Alpha Telescope, EI88 (GRS-A Code)

Facts in Brief

Mass: 5 kg
Power (avg): 2.6 W


  • Space Physics: Magnetospheric Studies

Additional Information

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



NameRoleOriginal AffiliationE-mail
Dr. Dieter K. HovestadtPrincipal InvestigatorMax-Planck-Institut fur Extraterrestrische Physik
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