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Proton-Electron Detectors

NSSDCA ID: 1962-068A-03

Mission Name: Relay 1
Principal Investigator:Prof. Carl E. McIlwain


Instrumentation for this experiment consisted of an ensemble of particle detectors. An omnidirectional plastic scintillator, detector A, measured the sum of counts due to protons above 34 MeV and electrons above 3.7 MeV. Using magnetometer gating, the remaining detectors (B, C, D) and associated electronic discrimination circuitry measured fluxes of approximately locally mirroring particles. A solid-state surface barrier detector (B) measured protons in the nested intervals 1.1 to 14 MeV, 1.6 to 7.1 MeV, and 2.25 to 4.7 MeV. A two-element, solid-state telescope (C) measured protons in the energy intervals 18.2 to 25 MeV, 25 to 35 MeV, and 35 to 63 MeV. A plastic scintillator (D) measured in four discrimination states the sums of protons with energies above 5.2 MeV and electrons with energies above 0.30, 0.45, 0.62, and 0.82 MeV, respectively. Background counts were accumulated by these detectors when their axes were not perpendicular (to within 10 deg) to the local magnetic field. Detector A cumulative counts were telemetered every second. Detectors B, C, and D directional flux data were transmitted as follows during successive 12-s intervals every 48 s. Counts from the various discrimination states of a given detector were each telemetered once per second while accumulating for 10 s. (The spacecraft spin period was approximately 0.37 s.) Two redundant readouts followed the cessation of counting. Most useful data were telemetered between launch and October 20, 1964. Detector B provided no useful data after May 10, 1963. NSSDC has all the data that now exist from this investigation.

Alternate Names

  • Relay1/Proton-ElectronDetectors


  • 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. R. Walker FilliusOther InvestigatorUniversity of California, San
Prof. Carl E. McIlwainPrincipal InvestigatorUniversity of California, San
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