Radiation aging studies of CO/sub 2/ hydrocarbon mixtures for the SLD drift chamber

The SLD drift chamber requires a 'slow' drifting gas and low diffusion to allow wave form digitization. CO/sub 2/ provides this but requires an admixture of a quencher to provide more gain. A test chamber with an 8 sense wire cell, such as will appear in the final chamber, was exposed to an X-ray tube while containing a variety of binary admixtures of CO/sub 2/: 8% isobutane, 8% ethane, and 2% isopropanol. It was determined that adding small fractions of water (with