A fast transition radiation detector for high-energy particles selection and triggering

In this paper we exploit the capability of a transition radiation detector to select different mass particles in a high-energy unseparated beam and to provide a prompt identification signal that can be used as a first level trigger for the physical event acquisition. Various studies on prototypes and measurements on electron/hadron test beams at CERN and BNL are presented: on the basis of the results obtained we show that we can promptly separate electrons from pions starting from 1 GeV/c momentum and we discuss about the possibility to distinguish as well pions from protons in the hundred GeV/c range of momentum at the level of a few percent of particle mis-identification.