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Cosmic-ray time scales using radioactive clocks

Yanasak, N. E. and Wiedenbeck, M. E. and Binns, W. R. and Christian, E. R. and Cummings, A. C. and Davis, A. J. and George, J. S. and Hink, P. L. and Israel, M. H. and Leske, R. A. and Lijowski, M. and Mewaldt, R. A. and Stone, E. C. and von Rosenvinge, T. T. (2001) Cosmic-ray time scales using radioactive clocks. Advances in Space Research, 27 (4). pp. 727-736. ISSN 0273-1177. doi:10.1016/S0273-1177(01)00114-4.

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Radionuclides in the galactic cosmic rays serve as chronometers for measuring the characteristic time of physical processes affecting cosmic ray energy spectra and composition. The radionuclide ^(59)Ni, present in the ejecta of supernovae, will decay to ^(59)Co via electron-capture with a halflife of T_(1/2) = 7.6 × 10^4 yr. However, if the cosmic ray acceleration time scale is shorter than the decay halflife, ^(59)Ni will become fully-stripped of electrons and will be present in the cosmic rays. Abundances of cosmic ray ^(59)Ni and ^(59)Co measured with the Cosmic Ray Isotope Spectrometer (CRIS) are consistent with the decay of all source ^(59)Ni, implying an acceleration time delay > 10^5 yr. Abundances of the β-decay radioactive secondaries, produced by fragmentation of the cosmic rays during transport in the interstellar medium (ISM), depend on the time scales for spallation and escape from the Galaxy. Consequently, measurement of these abundances can be used to derive the galactic confinement time, τ_(esc), for cosmic rays. Using the abundances of the β-decay species ^(10)Be, ^(26)Al, ^(36)Cl, and ^(54)Mn measured by CRIS, we find a confinement time τ_(esc) ∼ 15 Myr.

Item Type:Article
Related URLs:
URLURL TypeDescription
Wiedenbeck, M. E.0000-0002-2825-3128
Binns, W. R.0000-0001-6110-3407
Christian, E. R.0000-0003-2134-3937
Cummings, A. C.0000-0002-3840-7696
Israel, M. H.0000-0002-8104-208X
Leske, R. A.0000-0002-0156-2414
Mewaldt, R. A.0000-0003-2178-9111
Stone, E. C.0000-0002-2010-5462
Additional Information:© Published by Elsevier Science Ltd on behalf of COSPAR. Available online 3 August 2001. This work was supported by NASA (under NAG5-6912} at the California Institute of Technology, the Jet Propulsion Laboratory, Washington University, and Goddard Space Flight Center.
Group:Space Radiation Laboratory
Funding AgencyGrant Number
Washington UniversityUNSPECIFIED
Goddard Space Flight CenterUNSPECIFIED
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Space Radiation Laboratory2001-59
Issue or Number:4
Record Number:CaltechAUTHORS:20140826-115932195
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Official Citation:N.E. Yanasak, M.E. Wiedenbeck, W.R. Binns, E.R. Christian, A.C. Cummings, A.J. Davis, J.S. George, P.L. Hink, M.H. Israel, R.A. Leske, M. Lijowski, R.A. Mewaldt, E.C. Stone, T.T. von Rosenvinge, Cosmic-ray time scales using radioactive clocks, Advances in Space Research, Volume 27, Issue 4, 2001, Pages 727-736, ISSN 0273-1177, (
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:48918
Deposited On:26 Aug 2014 20:28
Last Modified:10 Nov 2021 18:37

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