RATE EFFECTS IN RADIATION DETECTORS WITH RESISTIVE ELECTRODES

Detectors with highly resistive electrodes, particularly RPCs, have be en studied extensively in recent years. Several authors considered the effect of rate on the detector response (efficiency) and a few also a ssociated with the rate, in a rather qualitative manner, the charge pe r event, i.e., the current. Here, without loss of generality of the re sults obtained, rate effects are studied with a classical cylindrical counter geometry and different gas mixtures. To a high accuracy, the o bserved behavior, both for the proportional mode and for the transitio n to streamers, is quantitatively and accurately interpreted as loss o f voltage on the dielectric due to the current generated in the detect or, with direct consequences for the local electric field in the avala nche region. Results obtained in the self quenching streamer (SQS) mod e fail the previous interpretation and clearly need further research.