Gas Cherenkov detectors for high momentum charged particle identification in the ALICE experiment at LHC

Protons identification up to 10GeV/c and more is a challenge. We present here an exhaustive study of the possibilities offered by a combination of a gaseous radiator having low index of refraction (C5F12) with the proven concept of large area CsI photocathodes, instrumenting either a multiwire chamber or a GEM detector. We present two geometries. One of them is proximity-focusing, nevertheless allows identification in a large momentum range. The second one deals with a focusing geometry with a spherical mirror. Simulations of the performance of both types are presented.