Measurement of Ionization Loss in the Relativistic Rise Region with the Time Projection Chamber

We present here some results obtained with the LBL Time Projection Chamber (TPC) regarding the particle identification by the measurement of the ionization losses in the relativistic rise region. This includes the method of calibration using 55Fe sources, the measurement of the resolution using cosmic rays, which shows an equivalent K-π separation of 4.8 standard deviations at 3.5 GeV/c, and the preliminary results obtained with multihadronic events from e+e- annihilations.