Measurement of electron drift parameters for He- and CF4-based gases

Summary form only given. Some properties of He- and CF/sub 4/-based gas mixtures have been measured. These mixtures may be important for obtaining either high electron drift speed or low mass medium in the drift chambers used in the future hadron colliders or electron-positron factories. The measured properties include electron drift velocities, single electron longitudinal diffusion including its contribution near the wire, the effect of water addition on both above quantities, a new method of purification of CF/sub 4/ gases, single-electron pulse height measurements including fitting to a Polya function, quenching properties, and some wire aging results.<>