Abundances of Ultra-Heavy Galactic Cosmic Rays from the SuperTIGER Instrument
The SuperTIGER (Trans-Iron Galactic Element Recorder) experiment was launched on a long-duration balloon flight from Williams Field, Antarctica, on December 8, 2012. SuperTIGER flew for a total of 55 days at a mean atmospheric depth of 4.4 g/cm^2. The instrument measured the abundances of galactic cosmic rays in the charge (Z) range Z ≥ 10 with excellent charge resolution, displaying well resolved individual element peaks for 10 ≤ Z ≤ 40. SuperTIGER collected ∼ 3.95 × 10^6 Iron nuclei, ∼ 7.1 times as many as detected by TIGER. We will present details of the data analysis techniques and the elemental abundances in the range 30 ≤ Z ≤ 40. The data presented contain more than 600 events in this charge range, with charge resolution at _(26)Fe of < 0.18 cu. Our measured abundances are generally consistent with those measured by TIGER and ACE. Our results confirm the earlier results from TIGER, supporting a model of cosmic-ray origin in OB associations, with preferential acceleration of refractory elements over volatile elements.
Additional InformationCopyright owned by the author(s) under the term of the Creative Commons Attribution-NonCommercial-ShareAlike. This research was supported by NASA under grants NNX09AC17G, NNX14AB25G, the Peggy and Steve Fossett Foundation, and the McDonnell Center for the Space Sciences at Washington University in St. Louis. We thank the NASA Columbia Scientific Balloon Facility, the NASA Balloon Program Office, and the NSF United States Antarctic Program for the excellent and highly professional efforts that resulted in the record long-duration balloon flight and recovery for SuperTIGER.
Published - ICRC2015_438.pdf