14C in lunar soil: temperature-release and grain-size dependence.
Abstract
C-14 is released from surface soils by heatings between 600 and 1000 C. The amounts of 600-1000-C C-14 obtained increase inversely with grain diameter for the 10-30 and 74-125-micron size fractions. The inverse relation shows that the 600-1000-C C-14 is located on the surface of grains and probably is of solar-wind origin. The amount released at these temperatures gives 0.002 C-14 ions per sq cm/sec for the implantation rate and corresponds to a C-14/H ratio of the order of 4 hundred-billionths for the solar wind. This result from the grain-size dependence is in accord with C-14 depth-variation studies. The C-14 released above melting temperatures can be attributed to spallation production.
- Publication:
-
Lunar and Planetary Science Conference Proceedings
- Pub Date:
- 1977
- Bibcode:
- 1977LPSC....8.3749F
- Keywords:
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- Carbon 14;
- Lunar Soil;
- Solar Wind;
- Temperature Effects;
- Grain Boundaries;
- Ion Implantation;
- Lunar Composition;
- Lunar Surface;
- Vertical Distribution;
- Lunar and Planetary Exploration