Pk. Kuroda et Wa. Myers, PU-244 DATING .9. FISSION XENON IN CARBONACEOUS CHONDRITES, Journal of radioanalytical and nuclear chemistry, 173(2), 1993, pp. 219-227
Re-examination of a vast amount of xenon isotope data which have been
accumulated since the 1960s reveals that the so-called CCF (carbonaceo
us chondrite fission) xenon is a mixture of Pu-244 fission xenon and a
severely mass-fractionated primordial xenon, whose isotopic compositi
on has been further altered by neutron-capture and spallation reaction
s, which occurred in the vicinity of a supernova that most likely expl
oded sometime more than 4.8 billion years ago. T integrated flux of 10
KeV (stellar temperature) neutrons to which the xenon was exposed app
ears to have been in excess of 10(23) n/cm2.