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Abstract-We present Ne data from plagioclase separates from the solar noble-gas-rich meteorite Kapoeta, obtained mainly by in vucuo etching. Samples rich in solar gases contain an excess of cosmogenic Ne compared to solar-gas-poor samples, testifying to an exposure to cosmic rays in the parent body regolith. The 21Ne/22Ne ratio of the excess component is slightly lower than that of the Ne acquired during the meteoroid flight. Model calculations indicate that the observed isotopic composition of the excess Ne can be produced by galactic cosmic rays at a reasonable mean shielding of around a hundred to a few hundred grams per square centimeter. No substantial contribution from Ne produced by solar cosmic rays is needed to explain the data. We therefore conclude that they do not offer evidence for a substantially enhanced flux of solar energetic particles early in solar history, contrary to other claims. This conclusion is in agreement with solar flare track data.

This paper is dedicated to Peter Signer on his 65th birthday.Abstract-Solar noble gases He, Ne, Ar and Kr implanted in the H3-6 meteorite regolith breccia Acfer III agree in their elemental composition with that in present-day solar wind and, except for a 25% deficit of 4He, also with adopted solar abundances. The presence of such unfractionated solar gases makes Acfer III unique (until now). Closed system stepped etching releases noble gases that can be explained as mixtures oftwo distinct types of He, Ne, and Kr of isotopic compositions as they have been derived previously from meteorites and lunar samples that contain heavily fractionated solar gases. Since the same putative end members, ascribed to the solar wind (SW) and supra-thermal solar energetic particles (SEP), are also present in Acfer Ill, we argue that these end members represent two truly independent components. We discount the possibility that one isotopic composition derived from the other by diffusion ofthe gases within, or upon their release from, their host phases. The isotopic signatures of noble gases in Acfer III agree with those in a lunar ilmenite of young antiquity ""100 Ma) but are in disagreement with the noble gases in lunar ilmenite 79035 of 1-2 Ga antiquity. Systematic changes are discussed of the nuclide abundance ratios as etching proceeds; they are ascribed to differences in trapping efficiency and in penetration depth of the different noble gas ion species upon their implantation.