The micro-Resis7ve WELL detector for the phase 2 upgrade of the LHCb muon detector

he LHCb experiment is a single-arm spectrometer dedicated to the study of the CP viola7on and other rare phenomena in the decay of Beauty par7cles. One of its feature is a fast and versa7le trigger system to select the interes7ng events. The apparatus is designed like a fixed-target experiment due to the very forward peaked b-quark distribu7on at LHC. It is composed of five systems: vertexing, tracking, ring cherenkov detectors, the calorimeters and the muon system. Up to the end of 2017 LHCb has recorded a total luminosity of 7 g-1 and in the next year, since LHC is going to increase its luminosity, the apparatus needs to upgrade its system. For the first phase only the replacement of the FEE will be done. For the phase 2, the detectors should show a rate capability up to 3 MHz/cm2, an efficiency for single gap > 95% within 25 ns (BX), stability up to 6 C/cm2 integrated charge in 10 y at G=4000. So we propose for this upgrade the micro-Resis7ve WELL.