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Low pressure radon diffusion - A laboratory study and its implications for lunar ventingResults of a study of radon migration through columns of fine particulate materials, at total pressures of 0.02-0.2 torr, are reported. Materials studied were: NBS Glass Spheres (SRM 1003), Emerson & Cuming Eccospheres (IG-101), activated coconut charcoal, Lipaci obsidian, and W-1 Standard Diabase. Rates of diffusion were used to derive heats of adsorption for radon on the materials tested. The most reliable values found clustered around 8-9 kcal/mole. These high heats of adsorption, if typical for most materials, combined with low percentages of radon emanation by lunar soils found by other researchers, imply that random walk diffusion will not be an important mechanism for redistributing the radon and the radon daughters produced in the lunar regolith. In particular, since random walk migration is not a sufficient mechanism to account for localized high concentrations of radon-222 and its daughter polonium-210 observed by the Apollo 15 and 16 command modules, an alternative mechanism is proposed, in which radon would be swept to the surface by other gases during intermittent venting events.
Document ID
19760046614
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Friesen, L. J.
(Georgia, University Athens, Ga., United States)
Adams, J. A. S.
(Rice University Houston, Tex., United States)
Date Acquired
August 8, 2013
Publication Date
April 1, 1976
Publication Information
Publication: Geochimica et Cosmochimica Acta
Volume: 40
Subject Category
Lunar And Planetary Exploration
Accession Number
76A29580
Funding Number(s)
CONTRACT_GRANT: NGR-44-006-142
Distribution Limits
Public
Copyright
Other

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