Measurement of the relative abundances of the ultra-heavy galactic cosmic rays (30 ≤ Z ≤ 40) with the Trans-Iron Galactic Element Recorder (TIGER) instrument

The Trans-Iron Galactic Element Recorder (TIGER) is a long duration balloon (LDB) borne instrument designed to measure the relative elemental abundances of the ultra-heavy (UH) (30 ≤ Z ≤ 40) galactic cosmic rays (GCR). TIGER measures charge (Z) and energy ( E) using a combination of four scintillator and two Cherenkov detectors, and employs a scintillating fiber hodoscope for event trajectory determination. TIGER has made two successful flights from McMurdo, Antarctica in December of 2001 and 2003 for a combined flight time of over 50 days. The data from each flight have been analyzed to correct for instrument effects and to eliminate events interacting in the instrument. The relative elemental abundances of the GCR source (GCRS) have been derived using atmospheric and interstellar propagations of the relative abundances for the combined TIGER dataset. The TIGER GCRS results agree best with an OB-association/super-bubble environment model with a source composition comprised of 20% supernova and Wolf-Rayet processed material mixed with 80% Solar System (SS) material, and with preferential acceleration ordered by chemical volatility and atomic mass (A).