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Published 2001 | public
Journal Article

The isotopic source composition of cosmic-ray iron, cobalt, and nickel


The isotopic composition of cosmic-ray Fe, Co, and Ni at energies ∼150–500 MeV/nucleon has been measured with the Cosmic-Ray Isotope Spectrometer (CRIS) instrument on ACE. Source abundances have been derived from a leaky-box propagation model using secondary species in the range 41 ≤ A ≤ 55 to constrain the calculated secondary contributions to the Fe, Co, and Ni isotopes. The derived relative source abundances bear a strong resemblance to solar-system values. The most significant difference, an excess of ∼ (70 ± 30)%, is found for the source abundance ratio ^(58)Fe/^(56)Fe. Some implications of the derived source composition for the origin of cosmic rays are discussed.

Additional Information

© 2001 COSPAR. Published by Elsevier Science Ltd. Available online 3 August 2001. This research was supported by the National Aeronautics and Space Administration at the California Institute of Technology (under grant NAG5-6912), the Jet Propulsion Laboratory, NASA's Goddard Space Flight Center, and Washington University.

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August 19, 2023
October 17, 2023