New developments on resistive plate chambers for high rate operation

A gas detector with parallel resistive electrodes has intrinsic capability of efficient detection at high particle fluxes. An inverted Double Gap Resi stive Plate Chamber made of special bakelite of low resistivity - rho = 5.1 0(8) Omega cm, reaches full efficiency with a plateau exceeding 500 V for r adiation rates as high as 7 kHz/cm(2) measured with a periodic beam. A gas mixture containing a majority of so called "green freon" - C2H2F4 assures s table avalanche amplification with a time resolution of about 2 ns, only sl ightly dependent on the particle flux. Measurements with a strong Cs-137 source confirm stability of parameters in continuous radiation flux up to 5 kHz/cm(2)/gap. The results demonstrate t he usefulness of an RPC as a muon trigger detector in a high radiation back ground environment, expected in the CMS experiment in the highest rapidity region. (C) 1998 Elsevier Science B.V. All rights reserved.