The first Module0 MicroMegas Chamber for the New Small Wheel Upgrade of the ATLAS Muon Spectrometer: Features and Performances

After the second long shutdown (LS2) in 2019-2020, the LHC luminosity will be increased up to 2-3$\cdot$10$^{34}$ cm$^{-2}$ s$^{-1}$ in Phase$-$1 and eventually to 7$\cdot$10$^{34}$ cm$^{-2}$ s$^{-1}$ in the High Luminosity LHC era. While high luminosity will provide more data, it is essential that the ATLAS detectors are still able to operate in the higher background environment maintaining their performances as good as that at lower luminosities. To obtain this, some of the detectors that are located nearest to the beam pipe have to be replaced. For the upgrade of the ATLAS Muon Spectrometer the present Small Wheel equipped with CSC, MDT and TGC chambers will be replaced the New Small Wheel. This will contain two new detector types: the MicroMegas (MM) and the small-strip TGC (sTGC). The first Module-0 of Micromegas quadruplet has been built by a consortium of several INFN groups in Italy and tested with high energy particles at the H8 SPS Test Beam experimental area at CERN in June 2016. The construction of the Module and the results obtained at the test-beam are reported.