Plutonium-244 dating I. Initial ratio of plutonium to uranium in the allende meteorite

Re-examination of all known xenon isotope data for the carbonaceous chondrite Allende reveals that this meteorite contains as much as (22±1)·10−1 2 csSTP per gram of fissogenic136Xe (136fXe) from the extinct nuclide244Pu and it appears to have started to retain its xenon more than 4800 million years ago, when the244Pu to238U ratio in the solar system was 0.113±0.006 (atom/atom).