The Cosmic Ray ^3He/^4He Ratio from 200 MeV/nucleon^(-1) to 3.7 GeV/nucleon^(-1)
Abstract
The abundances of cosmic-ray helium isotopes between 0.2 and 3.7 GeV nucleon^(-1) were measured by the Isotope Matter Antimatter Experiment (IMAX) during a flight from Lynn Lake, Manitoba, Canada on 1992 July 16-17. The IMAX balloon-borne magnetic spectrometer realized a direct measurement of the charge, the velocity, and the rigidity of cosmic rays using plastic scintillators, a high-resolution time-of-flight system, and two silica-aerogel Cerenkov counters in conjunction with a drift chamber/multiwire proportional chamber tracking system. About 75,000 helium isotopes are identified by their mass using the velocity versus magnetic rigidity technique. The measured ^3He/^4He ratios are corrected to the top of the atmosphere, and a comparison with previous data is given. The observed isotopic composition is found to be generally consistent with the predictions of a standard leaky box model of cosmic-ray transport in the Galaxy.
Additional Information
Received 1997 May 19, accepted for publication 1997 October 24. 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 Scientific Balloon Facility for carrying out a successful flight 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 Bundesrninisterium ftir Bildung, Wissenschaft, Forschung, und Technologie (BMBF).Attached Files
Published - 0004-637X_496_1_490.pdf
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Additional details
- Alternative title
- The Cosmic Ray 3He/4He Ratio from 200 MeV/nucleon-1 to 3.7 GeV/nucleon-1
- Eprint ID
- 50742
- DOI
- 10.1086/305358
- Resolver ID
- CaltechAUTHORS:20141023-131745397
- NASA
- RTOP 353-87-02
- NASA
- NAGW-1418
- NASA
- NAGW- 1919
- Deutsche Forschungsgemeinschaft (DFG)
- Bundesministerium fur Bildung, Wissenschaft, Forschung, und Technologie
- Created
-
2014-11-20Created from EPrint's datestamp field
- Updated
-
2021-11-10Created from EPrint's last_modified field
- Caltech groups
- Space Radiation Laboratory
- Other Numbering System Name
- Space Radiation Laboratory
- Other Numbering System Identifier
- 1997-24