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Cesium Iodide Dosimeters

NSSDC ID: 1966-073A-04
Mission Name: Lunar Orbiter 1
Principal Investigator: Dr. Trutz Foelsche


The principle 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 in the loopers. The shielding thickness of the cassette and cassette dosimeter was 2 cm/sq sm 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.


  • Space Physics: Heliospheric Studies

Additional Information

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Name Role Original Affiliation E-mail
Dr. Trutz Foelsche Principal Investigator NASA Langley Research Center  
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