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Measurements of the Isotopic Composition of Anomalous Cosmic Ray N, O, and Ne from ACE

Leske, R. A. and Mewaldt, R. A. and Christian, E. R. and Cohen, C. M. S. and Cummings, A. C. and Stone, E. C. and von Rosenvinge, T. T. and Wiedenbeck, M. E. (1999) Measurements of the Isotopic Composition of Anomalous Cosmic Ray N, O, and Ne from ACE. In: Proceedings of the 26th International Cosmic Ray Conference. Vol.7. International Union of Pure and Applied Physics , pp. 539-542.

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We have measured the elemental and isotopic composition of anomalous cosmic rays (ACRs) with energies > 8 Me V /nucleon during solar quiet periods between August 1997 and March 1998, using the Solar Isotope Spectrometer (SIS) on the Advanced Composition Explorer (ACE). The capabilities of the SIS instrument allow the examination of spectra of individual ACR isotopes. In addition to the well-known low-energy ACR enhancements in the intensity of elemental 0 and Ne, similar enhancements are found in ^(18)O and ^(22)Ne, with relative abundances of ^(18)O/^(16)O ~ 0.002 and ^(22)Ne/(20)Ne ~ 0.1. The neon abundance ratio appears more similar to that found in the solar wind than in meteorites, and is far below that deduced for the galactic cosmic ray (GCR) source, indicating that GCRs are not simply an accelerated sample of the local interstellar medium.

Item Type:Book Section
Related URLs:
URLURL TypeDescription
Leske, R. A.0000-0002-0156-2414
Mewaldt, R. A.0000-0003-2178-9111
Christian, E. R.0000-0003-2134-3937
Cohen, C. M. S.0000-0002-0978-8127
Cummings, A. C.0000-0002-3840-7696
Stone, E. C.0000-0002-2010-5462
Wiedenbeck, M. E.0000-0002-2825-3128
Additional Information:Copyright University of Utah. Provided by the NASA ADS. We thank the technical crews from New Mexico State University, Goddard Space Flight Center, California Institute of Technology, and the Universitat Siegen for their dedicated support. We are grateful to the National ScientiÐc Balloon Facility for carrying out a successful Ñight of the IMAX payload. The IMAX project was supported in the United States by NASA under RTOP 353-87-02 (GSFC) and grants NAGW-1418 (NMSU/BBMF) and NAGW-1919 (Caltech) and in Germany by the Deutsche Forschungsgemeinschaft (DFG) and the Bundesministerium fur Bildung, Wissenschaft, Forschung, und Technologie (BMBF).
Group:Space Radiation Laboratory
Funding AgencyGrant Number
NASARTOP 353-87-02
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Other Numbering System NameOther Numbering System ID
Space Radiation Laboratory.1999-22
Record Number:CaltechAUTHORS:20150212-103610912
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:54779
Deposited By: Deborah Miles
Deposited On:13 Feb 2015 19:41
Last Modified:09 Mar 2020 13:19

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