Cosmogenic-Nuclide Production by Primary Cosmic-Ray Protons

摘要

The production rates of cosmogenic nuclides were calculated for the primary protons in the galactic and solar cosmic rays. At 1 AU, the long-term average fluxes of solar protons usually produce many more atoms of a cosmogenic nuclide than the primary protons in the GCR, the exceptions being nuclides made only by high-energy reactions (like Be-10). Because the particle fluxes inside meteorites and other large objects in space include many secondary neutrons, the production rates and ratios inside large objects are often very different from those by just the primary GCR protons. Thus it is possible to determine, by examining its cosmogenic nuclides, if a small object, such as found among deep-sea spherules, was small in space or broken from a meteorite. Because heliospherical modulation and other interactions change the GCR particle spectrum, the production of cosmogenic nuclides by the GCR particles outside the heliosphere will be different from that by modulated GCR primaries. Production rates and ratios for cosmogenic nuclides would be able to identify small particles, possibly interstellar in origin, that were exposed to an unmodulated spectrum of GCR particles and to characterize the spectrum of particles to which they were exposed. 6 refs., 1 tab. (ERA citation 10:037920)