Ageing measurements on glass RPCs

Resistive plate chambers are widely used as active elements in particle physics detectors. A deterioration of RPC performance with time has been observed in several experiments, after operation at high temperature or with water contamination in the gas mixture, both for detectors with bakelite electrodes and for the ones with float-glass electrodes. We have developed a kind of RPCs suitable for large scale industrial production. Float-glass is employed as electrode material, and the screen-printing technique is used to apply the resistive coating on the electrodes. A dedicated intensive measurement program on these detectors has been carried out, to assess their long term behaviour and ageing properties under different operational conditions.