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Measurement of the Secondary Radionuclides ^(10)Be, ^(26)Al, ^(36)Cl, ^(54)Mn, and ^(14)C and Implications for the Galactic Cosmic-Ray Age

Yanasak, N. E. and Wiedenbeck, M. E. and Mewaldt, R. A. and Davis, A. J. and Cummings, A. C. and George, J. S. and Leske, R. A. and Stone, E. C. and Christian, E. R. and von Rosenvinge, T. T. and Binns, W. R. and Hink, P. L. and Israel, M. H. (2001) Measurement of the Secondary Radionuclides ^(10)Be, ^(26)Al, ^(36)Cl, ^(54)Mn, and ^(14)C and Implications for the Galactic Cosmic-Ray Age. Astrophysical Journal, 563 (2). pp. 768-792. ISSN 0004-637X. https://resolver.caltech.edu/CaltechAUTHORS:20140827-082013151

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Abstract

We report on abundance measurements of ^(10)Be, ^(26)Al, ^(36)Cl, and ^(54)Mn in the Galactic cosmic rays (GCRs) using the Cosmic-Ray Isotope Spectrometer (CRIS) instrument aboard the Advanced Composition Explorer spacecraft at energies from ~70 to ~400 MeV nucleon^(-1). We also report an upper limit on the abundance of GCR ^(14)C. The high statistical significance of these measurements allows the energy dependence of their relative abundances to be studied. A steady-state, leaky-box propagation model, incorporating observations of the local interstellar medium (ISM) composition and density and recent partial fragmentation cross section measurements, is used to interpret these abundances. Using this model, the individual galactic confinement times derived using data for each species are consistent with a unique confinement time value of τ_(esc) = 15.0 ± 1.6 Myr. The CRIS abundance measurements are consistent with propagation through an average ISM hydrogen number density n_H = 0.34 ± 0.04 H atoms cm^(-3). The surviving fractions, f, for each radioactive species have been calculated. From predictions of the diffusion models of Ptuskin & Soutoul, the values of f indicate an interstellar cosmic-ray diffusion coefficient of D = (3.5 ± 2.0) × 10^(28) cm^2 s^(-1).


Item Type:Article
Related URLs:
URLURL TypeDescription
http://iopscience.iop.org/0004-637X/563/2/768PublisherArticle
http://dx.doi.org/10.1086/323842DOIArticle
ORCID:
AuthorORCID
Mewaldt, R. A.0000-0003-2178-9111
Alternate Title:Measurement of the Secondary Radionuclides 10Be, 26Al, 36Cl, 54Mn, and 14C and Implications for the Galactic Cosmic-Ray Age
Additional Information:© 2001 American Astronomical Society. Received 2000 October 6; accepted 2001 August 2. We gratefully acknowledge the individuals responsible for the development of the CRIS instrument (listed in Stone et al. 1998a). We appreciate the helpful discussion of Petr Vogel concerning theoretical calculations of the half-life of ^(54)Mn. We also thank the University of Chicago for providing Climax neutron monitor data (supported by National Science Foundation grant ATM 96-13963). 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, the Goddard Space Flight Center, Washington University, and the McDonnell Center for the Space Sciences at Washington University.
Group:Space Radiation Laboratory
Funders:
Funding AgencyGrant Number
NSFATM 96-13963
NASANAG5-6912
JPLUNSPECIFIED
Goddard Space Flight CenterUNSPECIFIED
Washington University McDonnell Center for the Space SciencesUNSPECIFIED
Subject Keywords:cosmic rays; Galaxy: general; Galaxy: halo; ISM: abundances
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Space Radiation Laboratory2001-34
Issue or Number:2
Record Number:CaltechAUTHORS:20140827-082013151
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20140827-082013151
Official Citation:Measurement of the Secondary Radionuclides 10Be, 26Al, 36Cl, 54Mn, and 14C and Implications for the Galactic Cosmic-Ray Age N. E. Yanasak et al. 2001 ApJ 563 768
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:48958
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:27 Aug 2014 18:20
Last Modified:22 Nov 2019 09:58

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