Aging measurements in wire chambers

A study of aging with dimethylether (DME), argon/carbon dioxide and carbon dioxide/isobutane was performed. The influence of the drift chamber construction materials, gas seal pastes and tubes on the aging rate was investigated. The radiation hardness of the KEDR drift chamber cell with DME was increased by an order of magnitude by appropriately selecting drift chamber and tubing materials. The gain dependence of the aging rate with DME was measured. An influence of the sense-wire surface quality on aging was observed. For an explanation of these results, a model of polymer film formation and growth was proposed and tested.