RATE EFFECTS IN A PROPORTIONAL COUNTER WITH RESISTIVE CATHODE

In this work, the rate effects associated with the gain of detectors w ith resistive electrodes are considered. To study these effects it was decided to use the classical proportional counter geometry, with a cy lindrical glass tube as the cathode, rather than parallel plate device s. Indeed, the generality of the information obtained is not affected and the cylindrical proportional counter geometry has several advantag es to gather detailed experimental data and to compare it with simple electric field calculations. A self-consistent set of data is presente d for the effects of counting rate from a few tens of Hz up to several hundreds of Hz, using several gas mixtures, different anode wires, ca thode radii and thickness of the resistive electrodes. Although a few sources of systematic errors can be identified, all the observed exper imental data can be quantitatively explained. Indeed, the measured gas amplification, from a few tens up to similar to 5 x 10(4) and for the range of counting rates quoted above, depends only on the local elect ric field as it should be expected. These results are directly relevan t to approach the problem of counting efficiency in resistive plate ch ambers. (C) 1998 Elsevier Science B.V. All rights reserved.