X. Workshop on Resistive Plate Chambers and Related Detectors

Recently developed micropattern gaseous detectors offer high position resolution, excellent rate characteristics and good time resolutions. However the fine structure of their metallic electrodes makes them very fragile and easily destroyable by occasional sparks. Our presentation will consist from two parts. In the first one we will review the latest efforts made from various groups to implement the resistive electrode approach to micropattern detectors technology with the aim to make these detectors similar to RPCs. The first of such successive attempts was made a few years ago by our team to GEM detector and several groups nowadays are experimenting in manufacturing and testing resistive GEMs made of different materials. Recently, a great success was also achieved in the case of MICROMEGAS detectors especially with its Ingrid and Gossip versions in which the anode plates together with the readout micropixels were coated with a SiO2 protective resistive layer. Currently in the framework of the RD51 collaboration several groups are developing conventional type MICROMEGAS with resistive anodes made of different materials and performing their beam test. In the second part our talk we will present a novel detector developed in the stream of these studies. It is a hybrid of RPC made by a parallel-plate avalanche chamber: a microgap gaseous detector with a resistive drift mesh and a resistive anode plate with outer metallic readout strips. The version with a fine pitch (50μm) strips located inside the anode gap was also successfully tested. The analysis shows that the latest design has a potential for an extremely good position resolution especially in the case of narrow drift gap. The new detector enables to considerably extend the RPC application since it features not only a high position resolution, but also a rather good energy resolution (18-20%FWHM for 6 keV) and if necessary can operate in cascaded mode. We will also report on our efforts to develop a much thinner resistive mesh which can be used in MICROMEGAS as well as in other micropttern detectors. The main conclusion from these works is that a resistive electrode approach applied to micropattern detectors makes them fully spark protected and thus we consider this direction as very promising.