A new generation of GEM detectors and their applications

Abstract

We have developed a new generation of gas electron multiplier (GEM)-like detectors with double-layered electrodes instead of the commonly used metallic ones: with an inner layer consisting of thin metallic strips and an outer layer made of a resistive grid manufactured by a screen printing technology on the top of these metallic strips. The cathode of this detector has been coated with a CsI layer making it sensitive to UV light. By measuring signals induced by avalanches on the inner metallic strips one can obtain 2-D information about the position of the avalanches. The resistive grid makes the detector intrinsically spark protected: in the case of sparks the resistive layer strongly restricts their current and thus the destructive power. Results of some preliminary studies demonstrating that the new GEMs with resistive grid coating can be used in applications such as RICH counters or for the readout of noble liquid dark-matter detectors.