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Published 1999 | Published
Book Section - Chapter Open

Measurements of the Isotopic Abundances of Galactic Cosmic Rays and Their Implications for Cosmic Ray Origin


We present measurements of the nickel and cobalt isotopes from the Cosmic Ray Isotope Spectrometer (CRJS) which was launched in August, 1997 aboard the NASA Advanced Composition Explorer (ACE). The objectives of CRJS are to measure the isotopic abundances and energy spectra of galactic cosmic rays ~GCRs) with 3 ≤ Z ≤ 30. We find that for these nuclei the measured ^5Ni/^(60)Ni and ^(59)Co/^(60)Ni ratios imply a time delay between nucleosynthesis and acceleration to cosmic ray energies of > 10^5 y.

Additional Information

© Copyright 1988 - 2015 - Astronomical Society of the Pacific. We are grateful to the large number of individuals that contributed significantly to the development of the CRIS instrument (listed in Stone et al. 1998). This research has been supported by NASA at the California Institute of Technology (grant NAG5-6912), the Goddard Space Flight Center, the Jet Propulsion Laboratory, Washington University in St. Louis.

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August 19, 2023
October 20, 2023