Speaker
Prof.
John Wefel
(Louisiana State University)
Description
The Advanced Thin Ionization Calorimeter (ATIC) balloon experiment
traveled to McMurdo, Antarctica four times, resulting in three successful
circumpolar flights: ATIC-1, a test flight; ATIC-2, a science flight; ATIC-3, a
balloon failure; ATIC-4, the final science flight. In particular, ATIC-4 provided
the data to understand the discrepancy between the H, He spectra reported
from ATIC-1 and 2 (the ATIC-1 results are withdrawn) and allowed an increase
in calorimeter depth by 25%, thereby yielding improved measurements of the
cosmic ray electron spectrum. ATIC results revealed the hardening in the very
high energy H and He spectra, provided new measurements of the spectra of
the major heavy nuclei and demonstrated the existence of an excess of cosmic
ray electrons in the sub-TeV energy range. The ATIC flights and the ATIC
science results are discussed in the context of other recent measurements and
astrophysical models.
Author
Prof.
John Wefel
(Louisiana State University)
