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Cesium Iodide Dosimeters

NSSDCA ID: 1967-041A-04

Mission Name: Lunar Orbiter 4
Principal Investigator:Dr. Trutz Foelsche


The principal purpose of the Lunar Orbiter radiation measuring systems was to monitor, in real time, particle fluxes that would damage processed film in case of major solar cosmic-ray events. This would make it possible for the mission control to minimize darkening of the film by operational maneuvers. A secondary purpose was to acquire a maximum amount of information on radiations on the way to the moon and near the moon. The sensor system consisted of two separately monitored thin cesium iodide scintillators (2-Pi solid angle acceptance) that were positioned and shielded in the same way as the film in the cassette and in the loopers. The shielding thickness of the cassette and cassette dosimeter was 2 gm/sq cm aluminum. The shielding of the loopers and the looper dosimeter was 0.17 gm/sq cm aluminum. These shielding thicknesses also corresponded approximately to the thickness of the Apollo module wall and of a space suit. In the case of protons at verticle incidence, particles with energy greater than 40 and 11 MeV penetrated 2 and 0.17 gm/sq cm, respectively.

Alternate Names

  • LunarOrbiter4/CesiumIodideDosimeters
  • Radiation Measurements


  • 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. Trutz FoelschePrincipal InvestigatorNASA Langley Research Center

Selected References

  • Foelsche, T., Radiation measurements in LO 1-5 (period August 10, 1966 - January 30, 1968), Unpublished, Unnumbered, 1968.
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