SuperTIGER Abundances of Galactic Cosmic-Rays for the Charge Interval Z=41-56

Abstract

On December 8, 2012 the SuperTIGER (Super Trans-Iron Galactic Element Recorder) instrument was launched from Williams Field, Antarctica on a long-duration balloon flight that lasted 55 days and maintained a mean altitude of 125,000 feet. SuperTIGER measured the relative abundances of Galactic cosmic-ray nuclei with high statistical precision and well resolved individual element peaks from Neon to Zirconium (charges Z=10-40). SuperTIGER also made exploratory measurements of the relative abundances up to Barium (Z=56). Although the statistics are low for elements heavier than Zirconium, we will show how the relative abundances of charges Z=41-56 compare to those reported by HEAO3-HNE during 1979-81. The relative abundances of elements Zirconium through Neodymium (Z=60) are of particular interest because they are likely formed both by supernova explosions and by binary neutron star mergers. A well resolved measurement of this range of elements can constrain the contributions to the Galactic cosmic-ray composition from both of these possible sources.

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