Cosmic results with the final Micromegas sectors for the ATLAS Muon upgrade

With the upgraded beam luminosity in LHC run-3, the detector technology for the innermost end-cap muon station (small wheel) of the ATLAS detector needs to be upgraded. The new technology should be able to meet the demands of keeping position resolution, high efficiency as well as fast response of the present system at the expected higher background rate, up to 20 kHz/cm2. The detectors for precision tracking and triggering at the New Small wheel (NSW) are Micromegas (MM) and small-strip Thin Gas Chamber (sTGC) respectively. The detectors are also complementary to each other. The Micromegas quadruplets are delivered at CERN from the different construction sites. Four Micromegas quadruplets are integrated to build a double wedge. After the electronic integration, the double wedges are tested with cosmic muons at the cosmic stand at CERN. The final high voltage configuration is verified, various parameters like the efficiency, cluster size, strip multiplicity per readout layers are measured. The double wedge of the Micromegas sector is qualified for the final integration with the sTGC wedges before mounting them on the NSW. The procedure and the cosmic test results of the final validation of Micromegas double wedges is presented.