Extinct lunar radioactivities: Xenon from 244Pu and 129I in Apollo 14 breccias

Plutonium-244 fission xenon and primordial xenon in lunar samples and meteorites

“…Table 4 shows the results of calculations which have been carried out on the xenon isotope data reported by REYNOLDS et al 54 for the Apollo 11 lunar fines 10084,59. The content of 244pu fission xenon 036fXe) thus calculated from the xenon isotope data reported by REYNOLDS et al is: 136fXe = (136Xe)~* = = (13,700)(0.0165)(10 10) = (6) = 226.10 12 (cm3STP/g) which is in reasonable agreement with the value of 212.10 12 cm3STP/g obtained earlier from the Apollo 11 lunar finesfl 5 Table 5 shows a comparison of the isotopic composition of the trapped xenon in the Apollo 11 lunar fines 10094, 59 and that of TAKAOKA'S 1 primitive xenon. The difference between the isotopic composition of xenon found in the bulk samples of 10084, 59 and that of the trapped xenon is again very small and hence it is virtually impossible to determine the content of 244pu fission xenon 036fXe) in this sample by the use of the graphical method alone.…”

“…BEHRMANN et al 59 also found an excess fission xenon component in the Apollo 14 lunar breccias 14318 and 14313 and reported that the gases were not due to in situ decay. Instead, they appeared to have been implanted in the surface crustal layer of the primitive moon nearly simultaneously with production by 244pu and 129I in the lunar interior.…”

Solar wind and other gases in the regoliths of the Pesyanoe parent object and the moon

“…In contrast to Pesyanoe, Xe data from many lunar breccia and soil samples plot well above the mixing line of 244 Pu-fission Xe and SWXe. Excess 128 Xe in lunar regolith samples may either be produced in situ by neutron-capture on 127 I or may indicate reimplanted "excess 128 Xe," as was extensively discussed for 129 Xe in regolith breccia samples (Behrmann et al 1973;Reynolds et al 1974;Swindle et al 1985). While the 128 Xe excesses in bulk lunar breccias are typically ~20 to 50‰, those in stepped releases are about twice as high, and lunar soils show a larger range in 128 Xe excesses of up to 150‰.…”

“…3 to 6 include the following published soil data: bulk and grain size separates of 10084, Apollo 12 fines, grain size separates of Apollo 15 fines, and Luna 16 fines; bulk, grain size, and ilmenite separates of 12001, bulk and grain size separates of Apollo 14, 15, and 17, bulk 67701, ilmenite separate of 71501, metal separate of 68501, bulk Apollo 17 deep drill core, and bulk 74261. The following lunar regolith breccia data are also included: 10046, 14301, 14318, 14313, 60019, 60275, 67455, 60255, and bulk and ilmenite separates of 79035 (Podosek et al 1971;Drozd et al 1972;Bogard and Nyquist 1972;Basford et al 1973;Behrmann et al 1973;Bogard et al 1974;Reynolds et al 1974;Bernatowicz et al 1978;Swindle et al 1985;Frick et al 1988;Pepin 1989, 1994;Wieler and Baur 1994;Eugster et al 2001). All Xe literature data are renormalized and corrected for spallation Xe components following the same procedure adopted for Pesyanoe.…”

Plutonium-244 in the early solar system and the Pre-Fermi natural reactor.

“…The case of sample 14301 soon ceased to be an exception and the presence of 244Pu fission xenon in lunar samples was reported by several investigators (see, for example, Drozd et al, 1972;Behrmann et al, 1973;Drozd et al, 1975Drozd et al, , 1976Swindle et al, 1985). These investigators have concluded that the excesses of 2`l4Pu fission xenon were not due to in situ decay of 244Pu, but they were "parentless".…”