33RD INTERNATIONAL COSMIC RAY CONFERENCE, RIO DE JANEIRO 2013 THE ASTROPARTICLE PHYSICS CONFERENCE In-flight Performance of the Super-TIGER Cherenkov Counters

Abstract: The Super-TIGER (Trans Iron Galactic Element Recorder) balloon payload completed its first flight from Antarctica (Dec 9, 2012-Feb 2, 2013). The instrument is designed to address the question of the sources of cosmic rays by precisely measuring the abundances of elements heavier than iron in the galactic cosmic radiation with high statistical accuracy and single charge resolution in the range 30 Z 42. In addition, it will provide exploratory charge measurements up to Z = 56. Super-TIGER has an effective geometrical acceptance that is 6.4 times larger than its predecessor TIGER. The first Super-TIGER flight recorded over 67.8 million CR events transmitted to the ground via TDRSS. For the charge identification of incident cosmic rays, the Super-TIGER instrument employs three layers of plastic scintillator, which can also reject interacting events in the detector, and two light-diffusion Cherenkov counters, one with an acrylic radiator (n = 1.49) and the other with a silica-aerogel radiator (n = 1.043 and 1.025). Each Cherenkov counter has an aperture of 118 cm x 240 cm and is 20 cm tall, is lined with highly reflective Gore-Tex, and is viewed by 42 5-inch Hamamatsu R877-100 photomultiplier tubes. In addition to a Z2 charge response, the Cherenkov counters also provide velocity information and allow for spectral information of the more abundan