Cosmic ray proton and helium spectra measured with BESS-TeV

In order to measure primary cosmic-ray spectra of protons and helium nuclei up to several hundred GeV/n, the BESS superconducting spectrometer was upgraded. We developed new drift chambers to obtain about one order higher momentum resolution. A balloon flight was performed at northern Canada, with a live data-taking time of 11 hours in August 2002. The whole detector system functioned as designed during the entire flight. The maximum detectable rigidity of 1.3 TV was achieved.