RPC simulation in avalanche and streamer modes using transport equations for electrons andions

A simulation of the development of a signal inside an RPC is presented using simultaneous solution of the transport equations for electrons, negative and positive ions. The simulation also includes effects of space-charge and photo-ionization which are important during the development of a streamer signal. In the results, three different modes of RPC operation can be distinguished; avalanche, saturated avalanche, and streamer. Especially in the streamer mode, in agreement with the experiments, the simulation clearly shows that a large signal is observed on the readout electrodes following a relatively small avalanche signal. This originates from the existence of both photo-ionization and space charges near the cathode produced by the primary avalanche signal, leading to the final streamer amplification.