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The Absolute Flux of Protons and Helium at the Top of the Atmosphere Using IMAX

Menn, W. and Hof, M. and Reimer, O. and Simon, M. and Davis, A. J. and Labrador, A. W. and Mewaldt, R. A. and Schindler, S. M. and Barbier, L. M. and Christian, E. R. and Krombel, K. E. and Krizmanic, J. F. and Mitchell, J. W. and Ormes, J. F. and Streitmatter, R. E. and Golden, R. L. and Stochaj, S. J. and Webber, W. R. and Rasmussen, I. L. (2000) The Absolute Flux of Protons and Helium at the Top of the Atmosphere Using IMAX. Astrophysical Journal, 533 (1). pp. 281-297. ISSN 0004-637X. doi:10.1086/308645.

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The cosmic-ray proton and helium spectra from 0.2 GeV nucleon^(-1) to about 200 GeV nucleon^(-1) have been measured with the balloon-borne experiment Isotope Matter-Antimatter Experiment (IMAX) launched from Lynn Lake, Manitoba, Canada, in 1992. IMAX was designed to search for antiprotons and light isotopes using a superconducting magnet spectrometer together with scintillators, a time-of-flight system, and Cherenkov detectors. Using redundant detectors, an extensive examination of the instrument efficiency was carried out. We present here the absolute spectra of protons and helium corrected to the top of the atmosphere and to interstellar space. If demodulated with a solar modulation parameter of Φ = 750 MV, the measured interstellar spectra between 20 and 200 GV can be represented by a power law in rigidity, with (1.42 ± 0.21) × 10^4R^(-2.71±0.04) (m^2 GV s sr)^(-1) for protons and (3.15 ± 1.03) × 10^3R^(-2.79±0.08) (m^2 GV s sr)^(-1) for helium.

Item Type:Article
Related URLs:
URLURL TypeDescription
Hof, M.0000-0003-2884-3037
Labrador, A. W.0000-0001-9178-5349
Mewaldt, R. A.0000-0003-2178-9111
Christian, E. R.0000-0003-2134-3937
Additional Information:© 2000. The American Astronomical Society. Received 1999 July 1; accepted 1999 November 23. We thank the technical crews from New Mexico State University, Goddard Space Flight Center, California Institute of Technology, and the Universität Siegen for their dedicated support. We are grateful to the National Scientific Balloon Facility for carrying out a successful flight of the IMAX payload. IMAX 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 für Bildung, Wissenschaft, Forschung und Technologie (BMBF).
Group:Space Radiation Laboratory
Funding AgencyGrant Number
NASARTOP 353-87-02
Deutsche Forschungsgemeinschaft (DFG)UNSPECIFIED
Bundesministerium für Bildung, Wissenschaft, Forschung und TechnologieUNSPECIFIED
Subject Keywords:cosmic rays; elementary particles; ISM: abundances
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Space Radiation Laboratory2000-14
Issue or Number:1
Record Number:CaltechAUTHORS:20150219-102725410
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:55002
Deposited By: Deborah Miles
Deposited On:23 Feb 2015 20:22
Last Modified:10 Nov 2021 20:40

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