The ATIC long duration balloon project

T. G. Guzik, Louisiana State University
J. H. Adams, NASA Marshall Space Flight Center
H. S. Ahn, University of Maryland, College Park
G. Bashindzhagyan, Lomonosov Moscow State University
J. Chang, Max Planck Institute for Solar System Research
M. Christl, NASA Marshall Space Flight Center
A. R. Fazely, Southern University and A&M College
O. Ganel, University of Maryland, College Park
D. Granger, Louisiana State University
R. Gunasingha, Southern University and A&M College
Y. J. Han, Seoul National University
J. B. Isbert, Louisiana State University
H. J. Kim, Seoul National University
K. C. Kim, University of Maryland, College Park
S. K. Kim, Seoul National University
E. Kouznetsov, Lomonosov Moscow State University
M. Panasyuk, Lomonosov Moscow State University
A. Panov, Lomonosov Moscow State University
B. Price, Louisiana State University
G. Samsonov, Lomonosov Moscow State University
W. K.H. Schmidt, Max Planck Institute for Solar System Research
E. S. Seo, University of Maryland, College Park
R. Sina, University of Maryland, College Park
N. Sokolskaya, Lomonosov Moscow State University
M. Stewart, Louisiana State University
A. Voronin, Lomonosov Moscow State University
J. Z. Wang, University of Maryland, College Park
J. P. Wefel, Louisiana State University
J. Wu, University of Maryland, College Park
V. Zatsepin, Lomonosov Moscow State University

Abstract

Long Duration Balloon (LDB) scientific experiments, launched to circumnavigate the south pole over Antarctica, have particular advantages compared to Shuttle or other Low Earth Orbit (LEO) missions in terms of cost, weight, scientific "duty factor" and work force development. The Advanced Thin Ionization Calorimeter (ATIC) cosmic-ray astrophysics experiment is a good example of a university-based project that takes full advantage of current LDB capability. The ATIC experiment is currently being prepared for its first LDB science flight that will investigate the charge composition and energy spectra of primary cosmic-rays over the energy range from about 10 10 to 10 14 eV. The instrument is built around a fully active, Bismuth-Germanate (BGO) ionization calorimeter to measure the energy deposited by cascades formed by particles interacting in a thick carbon target. A highly segmented silicon matrix, located above the target, provides good incident charge resolution plus rejection of "backscattered" particles from the cascade. Trajectory reconstruction is based on the cascade profile in the BGO calorimeter, plus information from the three pairs of scintillator hodoscope layers in the target section above it. A full evaluation of the experiment was performed during a test flight occurring between 28 December 2000 and 13 January 2001 where ATIC was carried to an altitude of ∼37 km above Antarctica by a ∼850,000 m 3 helium filled balloon for one circumnavigation of the continent. All systems behaved well, the detectors performed as expected, >43 GB of engineering and cosmic-ray event data were returned and these data are now undergoing preliminary data analysis. During the coming 2002-2003 Antarctica summer season, we are preparing for an ATIC science flight with ∼15 to 30 days of data collection in the near-space environment of Long Duration Balloon (LDB) float altitudes. © 2004 COSPAR. Published by Elsevier Ltd. All rights reserved.