Plutonium-244 and strange xenon components in the solar system

Abstract

A number of strange xenon components have been reported in the literature during the past three decades; for example, AVCC (average carbonaceous chondrite), CCF (carbonaceous chondrite fission) xenon, xenon-X, xenon-H, xenon-L, xenon-S, xenon-U, SUCOR (surface correlated xenon), BEOC (Bern Oberflachen-Correliert) xenon, and so on. It is often assumed that they reprsent the isotopic compositions of more or less ‘pure’ or ‘primordial’ components of xenon. If one attempts to interpret the existing xenon isotope data for meteorites and lunar samples, assuming that they are ‘pure’ or ‘primordial’, however, one encounters all sorts of problems and no coherent theory concerning the variation of the isotopic composition of xenon in the solar system emerges. We have therefore re-examined over 4,000 sets of existing xenon isotope data for meteorites and lunar samples. The results indicate that these strange xenon components are mixtures of244Pu fission xenon and atmospheric xenon, whose isotopic compositions have been altered by the processes of a) mass-fractionation, b) spallation and c) neutron-capture reactions.