The Pressurized de/Dx System in the Cleo Detector at Cesr

A unique part of the CLEO detector at CESR is the pressurized wire proportional chamber system for particle identification using measurements of ionization loss (dE/dx) in gaseous Argon. Each particle traversing the ~80 cm thick detector leaves 117 ionization samples. Data obtained from e+e- collisions at CESR in the 10 GeV center-of-mass energy region have been analyzed. Initial results showing the most probable ionization loss of hadrons and leptons as a function of their momenta will be presented. We describe the geometrical, mechanical and electrical construction of this device.