Plutonium-244 Fission Tracks: Evidence in a Lunar Rock 3.95 Billion Years Old
Abstract
Tracks attributed to the spontaneous fission of plutonium-244 and of uranium-238 were detected in a large whitlockite crystal in the lunar breccia 14321 from the Fra Mauro formation. For a track-retention age of 3.95 × 109 years the number of plutonium tracks relative to the number of uranium tracks is 0.51 ± 0.15, provided that the rock was not heavily neutron-irradiated 3.95 × 109 years ago.
- Publication:
-
Science
- Pub Date:
- May 1972
- DOI:
- 10.1126/science.176.4037.909
- Bibcode:
- 1972Sci...176..909H