Aging effects in gaseous detectors and search for remedies

Wire aging effects observed in the chambers of the ACCMOR spectrometer at CERN SPS are described, as well as results of laboratory tests performed to find solutions to this problem. In 50:50 Argon-Ethane gas mixture the loss of efficiency began after accumulating about 0.02 c/cm of anode wire, but the tests indicated that this limit can be extended to at least 0.1 C/cm by adding 0.1% iso-propylic alcohol. Analysis of wire deposits showed silicon, even with the alcohol added. Using sealed proportional counters, searches for nonpolimerizing gases were made including Argon-Nitrogen and Argon-CO2. With these two gases the lifetime is significantly improved, to about 0.1 - 1.0 C/cm, depending upon the gain or resolution requirements