H and He spectra from the 2004/05 CREAM-I flight

The balloon-borne Cosmic Ray Energetics And Mass (CREAM) payload flew for a record-breaking 42 days during the 2004/05 Antarctic season. The instrument incorporates a tungsten/scintillating-fiber sampling calorimeter and graphite targets to measure energies of nuclei. A finely segmented Silicon Charge detector (SCD) located above the targets is used for charge measurements. The position of the primary particle in the SCD is determined by backward extrapolation of the reconstructed shower axis in the calorimeter. The flight data have been analyzed using the latest calibration of the calorimeter. The energy spectra of proton, helium and their ratios will be presented in this paper.