Performance of the Advanced Thin Ionization Calorimeter (ATIC)
The ATIC instrument is a balloon-borne experiment capable of measuring cosmic ray elemental spectra from 50 GeV to 100 TeV for nuclei from H to Fe with a fully active Bismuth Germanate calorimeter. Several Long Duration Balloon flights from McMurdo station, Antarctica are scheduled. The detector was tested with high energy electron, proton, and pion beams at CERN. We present results for 150 and 375 GeV protons, and 150 GeV pions and comparison with a GEANT Monte Carlo.