Development of a Time Projection Chamber using CF4 gas for relativistic heavy ion experiments

A prototype Time Projection Chamber (TPC) using pure CF4 gas was developed for possible use in heavy ion experiments. Basic characteristics such as gain, drift velocity, longitudinal diffusion and attenuation length of produced electrons were measured with the TPC. At an electric field of 900 V/cm, the drift velocity and longitudinal diffusion for 1 cm drift were obtained as 10cm/μs and 60μm, respectively. The relatively large gain fluctuation is explained to be due to the electron attachment process in CF4. These characteristics are encouraging for the measurement of the charged particle trajectories under high multiplicity conditions at RHIC.