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M.E. Wiedenbeck N.E. Yanasak A.C. Cummings A.J. Davis J.S. George R.A. Leske R.A. Mewaldt E.C. Stone P.L. Hink M.H. Israel M. Lijowski E.R. Christian T.T. von Rosenvinge 《Space Science Reviews》2001,99(1-4):15-26
Cosmic-ray isotope observations from NASAs Advanced Composition Explorer (ACE) mission have been used to investigate the composition of cosmic-ray source material. Source abundances relative to 56Fe are reported for eleven isotopes of Ca, Fe, Co, and Ni, including the very rare isotopes 48Ca and 64Ni. Although the source abundances range over a factor 104, most of the ratios to 56Fe are consistent with solar-system values to within 20%. However, there are some notable differences, the most significant being an excess of (70±30)% relative to the solar system for the cosmic-ray source ratio 58Fe/56Fe. The possible association of such an excess with a contribution to the cosmic-ray source from Wolf–Rayet star ejecta is discussed. 相似文献
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R.A. Mewaldt N.E. Yanasak M.E. Wiedenbeck A.J. Davis W.R. Binns E.R. Christian A.C. Cummings P.L. Hink R.A. Leske S.M. Niebur E.C. Stone T.T. Von Rosenvinge 《Space Science Reviews》2001,99(1-4):27-39
There are a number of radioactive clocks in the cosmic radiation that can be used to measure the time scales for cosmic ray processes in the Galaxy. With high-resolution isotope measurements available from ACE it is now possible to read these clocks with greatly improved accuracy and address key questions about the origin and lifetime of cosmic rays. This paper discusses the status of three such investigations. 相似文献
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Stone E.C. Cohen C.M.S. Cook W.R. Cummings A.C. Gauld B. Kecman B. Leske R.A. Mewaldt R.A. Thayer M.R. Dougherty B.L. Grumm R.L. Milliken B.D. Radocinski R.G. Wiedenbeck M.E. Christian E.R. Shuman S. Trexel H. von Rosenvinge T.T. Binns W.R. Crary D.J. Dowkontt P. Epstein J. Hink P.L. Klarmann J. Lijowski M. Olevitch M.A. 《Space Science Reviews》1998,86(1-4):285-356
The Cosmic-Ray Isotope Spectrometer is designed to cover the highest decade of the Advanced Composition Explorer's energy
interval, from ∼50 to ∼500 MeV nucl−1, with isotopic resolution for elements from Z≃2 to Z≃30. The nuclei detected in this
energy interval are predominantly cosmic rays originating in our Galaxy. This sample of galactic matter can be used to investigate
the nucleosynthesis of the parent material, as well as fractionation, acceleration, and transport processes that these particles
undergo in the Galaxy and in the interplanetary medium.
Charge and mass identification with CRIS is based on multiple measurements of dE/dx and total energy in stacks of silicon
detectors, and trajectory measurements in a scintillating optical fiber trajectory (SOFT) hodoscope. The instrument has a
geometrical factor of ∼r250 cm2 sr for isotope measurements, and should accumulate ∼5×106 stopping heavy nuclei (Z>2) in two
years of data collection under solar minimum conditions.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
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