Relativistic Rise Measurement by Cluster Counting Method in Time Expansion Chamber

A new approach to the measurement of the ionization energy loss for the charged particle identification in the region of the relativistic rise was tested experimentally. The method consists of determining in a special drift chamber (TEC) the number of clusters of the primary ionization. The method gives almost the full relativistic rise and narrower "Landau" distribution. The consequences for a practical detector are discussed.