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Cosmic-Ray Proton (R vs DE/DX)

NSSDCA ID: 1967-051A-03

Mission Name: IMP-F
Principal Investigator:Dr. John A. Simpson


The experiment was designed to measure separately the contributions of solar nuclei and of galactic nuclei (Z<=14) using a solid-state cosmic ray telescope designed for energy-loss vs range or total energy measurements. The particle energy per nucleon intervals were approximately proportional to Z squared/A. For example, protons had intervals of 0.8 to 9.6 MeV, 9.6 to 18.8 MeV, 29.5 to 94.2 MeV, and 94.2 to 170 MeV and above. The detector viewing angle was perpendicular to the satellite spin axis. A second, smaller, solid-state telescope mounted parallel to the spacecraft spin axis was used to detect electrons in the ranges 80 to 130 keV and 175 to 390 keV. The electron detector was designed to provide information concerning the shape and intensity of the magnetospheric electron spectra. The detector accumulators for each energy interval were telemetered four times every 20.48 s. Each accumulation was 4.8 s long (spacecraft initial spin period was about 2.6 s). The output from three 256-channel nuclear-particle telescope pulse-height analyzers was obtained every 5.12 s and was telemetered along with the detector accumulators. The D3 element of the first telescope began to be intermittently noisy November 16, 1967, necessitating a more complex analysis to maintain data usefulness. After September 1968, no useful data above 30 MeV/nucleon were obtained. Otherwise, this telescope functioned until spacecraft reentry. The electron telescope provided useful data for only the first six days after launch. The instrument and its performance are discussed in detail in Garcia-Munoz, et al., Astrophys. J., v. 184, pp. 967-994, 1973.

Alternate Names

  • IMP-F/Cosmic-RayProton_RvsDE/DX_

Facts in Brief

Mass: 4.2 kg
Power (avg): 2.1 W
Bit rate (avg): 0.1 kbps

Funding Agency

  • NASA-Office of Space Science (United States)


  • Space Physics: Heliospheric Studies

Additional Information

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



NameRoleOriginal AffiliationE-mail
Dr. Gordon LentzGeneral ContactUniversity of Chicago
Dr. John A. SimpsonPrincipal InvestigatorUniversity of Chicago
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