Influence of chemical trace additives on the future ageing of the UA1 central detector

A number of systematic tests investigating the effect of various chemical additives on the ageing of prototypes of the UA1 Central Detector have been performed. In addition to the classical substances of water, ethanol and isopropanol emphasis is also put upon more uncommon chemicals, usually required as doping seeds for UV laser calibration. Chamber lifetime can be strongly influenced by them, depending on their concentration. Evidence is presented that proper choice and dosage can lead to a significant extension of normal wire chamber lifetime. (orig.)