A New Concept for Streamer Quenching in Parallel Plate Chambers

In this paper we propose a new concept for streamer quenching in Resistive Plate Chambers (RPCs). In our approach, the multiplication process is quenched by the appropriate design of a mechanical structure inserted between the two resistive electrodes. We show that stable performance is achieved with binary gas mixtures based on Argon and a small fraction of isobutane. Fluorocarbons, deemed responsible for the degradation of the electrode inner surface of RPC detectors, are thus fully eliminated from the gas mixture. This design also results in a much simplified assembly procedure. Preliminary results obtained with a few prototypes of "Mechanically Quenched RPCs" and some prospects for future developments are discussed.