A New GEM-like Imaging Detector with Electrodes Coated with Resistive Layers

We have developed and tested several prototypes of GEM-like detectors with electrodes coated with resistive layers. These detectors can operate stably at gains close to 10⁵ and if discharges appear at higher gains the protective layers restrict their energies so that they do not damage either the detector or the readout electronics. We discovered that the cathodes of these detectors could be coated by CsI layers and in such a way the detectors gain high efficiency for the UV photons. We also demonstrated that such detectors can operate stably in the cascade mode and high overall gains (~10⁶) are reachable. This opens applications in several areas, for example in RICH or in noble liquid TPCs. The simplified prototype of the RICH detector was built and successfully tested in the laboratory. The first results of operation of the new detectors at cryogenic temperatures are given.