The micro-Resistive WELL detector for the phase-2 upgrade of the LHCb muon detector

The μ -RWELL is a new generation Micro-Pattern Gaseous Detector, composed of two elements: the cathode and the μ -RWELL_PCB including the amplification stage, realized with a polyimide structure micro-patterned with a blind-hole matrix, embedded through a Diamond-Like Carbon (DLC) resistive layer with the readout PCB. Different layouts of the resistive stage have been studied: the simplest one is based on a single DLC layer with edge grounding, suitable for low rate applications (30–40 kHz/cm$^2$). More sophisticated schemes are under study for high-rate purposes (up to 2–3 MHz/cm$^2$) in order to optimize the performance and the constructive process. For the phase-2 upgrade of the LHCb muon detector the experiment is targeting a luminosity of 2×10$^{34}$ cm$^{-2}$ s$^{-1}$ , with strong requirements on the robustness and detection efficiency of the muon system. We report on the ongoing R&D;, showing also the latest measured performances of the new high-rate versions of the detector.