Isotopes of Krypton and Xenon Were Sorted by Mass
In 1972 measurements revealed that isotopes of spallation-free Kr (left) and Xe (right) in lunar soil #15601.64 had also been sorted by mass. Kr and Xr in AIR and in AVCC (Average Carbobaceous Chondrites) lie on these same mass-fractionation lines, except for the presence of excess Xe-129 in AIR from the decay of extinct I-129 in the Earth and the presence of excess Xe-134 and Xe-136 in lunar soils from fission. These are Figure 4 and Figure 8 of the paper by Srinivasan, Hennecke, Sinclair, and Manuel [Third Lunar Science Conference, vol. 2 (1972) 1927-1945].