Revised energy spectra for primary elements (H - Si) above 50 GeV from the ATIC-2 science flight
The Advanced Thin Ionization Calorimeter (ATIC) long duration balloon experiment had a successful science flight (12/02 -1/03) accumulating 18 days of data during a single circumnavigation of Antarctica. ATIC measures the energy spectra of elements from H to Fe in primary cosmic rays using a fully active Bismuth Germanate calorimeter preceded by a carbon target, with embedded scintillator hodoscopes, and a silicon matrix charge detector at the top. Preliminary results from ATIC have been reported in previous conferences. The revised results reported here are derived from a new analysis of the data with improved charge resolution, lower background and revised energy calibration. The raw energy deposit spectra are de-convolved into primary energy spectra and extrapolated to the top of the atmosphere. We compare these revised results to previous data.