The electron spectrum above 20 GeV measured by ATIC-2

J. Chang, Purple Mountain Observatory Chinese Academy of Sciences
W. K.H. Schmidt, Max Planck Institute for Solar System Research
J. H. Adams, George Marshall Space Flight Center
H. S. Ahn, University of Maryland, College Park
G. Bashindzhagyan, Lomonosov Moscow State University
K. E. Batkov, Lomonosov Moscow State University
M. Christl, Louisiana State University
A. R. Fazely, Southern University and A&M College
O. Ganel, University of Maryland, College Park
R. M. Gunasingha, Southern University and A&M College
T. G. Guzik, Louisiana State University
J. Isbert, Louisiana State University
K. C. Kim, University of Maryland, College Park
E. Kouznetsov, Lomonosov Moscow State University
M. Panasyuk, Lomonosov Moscow State University
A. Panov, Purple Mountain Observatory Chinese Academy of Sciences
E. S. Seo, University of Maryland, College Park
N. Sokolskaya, 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

The Advanced Thin Ionization Calorimeter (ATIC) Balloon Experiment has been flown from McMurdo, Antarctica in 2000-01 (test flight) and 2002-03 (science flight). ATIC is composed of a segmented BGO calorimeter following a carbon target with scintillator tracking layers and a Silicon matrix detector at the entrance. ATIC measures the composition and energy spectra of the nuclei plus electrons. We present the electron spectrum derived from the ATIC-2 science flight, from 20 GeV to 1.5 TeV, and compare it to existing very high energy measurements from emulsion chambers and to the results of galactic propagation calculations. The good energy resolution and high statistics in the ATIC data allow detailed astrophysical interpretation of the results.