Development of a prototype TPC with CF/sub 4/ & GEM readout for heavy ion collision

This article describes the R&D of Time Projection Chamber (TPC) for heavy ion collisions. A prototype TPC was developed for the R&D of CF/sub 4/ gas. It has a capability of using GEM readout. The characteristics of CF/sub 4/ is a small diffusion coefficient and large drift velocity. It is suitable for our purpose of heavy ion collisions. Characteristics of CF/sub 4/ gas, such as a diffusion coefficient and a drift velocity, were measured with the prototype TPC. In addition, a tracking resolution and sensitivities of double track separation and particle identification were measured using MWPC and pad readout. We achieved position resolution of 100 /spl mu/m with 2.5 mm square pads. For future use of a TPC readout, we have produced Gas Electron Multiplier (GEM) using a plasma etching method. Gain of the GEM was measured as a function of an applied voltage with an X-ray source. A gain of 104 was obtained in argon mixture gases.