ATLAS MPGD production status

Micromegas (MICRO MEsh GAseous Structure) chambers are Micro-Pattern Gaseous Detectors designed to provide a high spatial resolution and reasonable good time resolution in highly irradiated environments. In 2007 an ambitious long-term R\&D activity was started in the context of the ATLAS experiment, at CERN: the Muon ATLAS Micromegas Activity (MAMMA). After years of tests on prototypes and technology breakthroughs, Micromegas chambers were chosen as tracking detectors for an upgrade of the ATLAS Muon Spectrometer. These novel detectors will be installed in 2020 at the end of the second long shutdown of the Large Hadron Collider, and will serve mainly as precision detectors in the innermost part of the forward ATLAS Muon Spectrometer. Four different types of Micromegas modules, eight layers each, up to $3 m^2$ area (of unprecedented size), will cover a surface of $150 m^2$ for a total active area of about $1200 m^2$. With this upgrade the ATLAS muon system will maintain the full acceptance of its excellent muon tracking at the highest LHC luminosities expected in the third run of the Large Hadron Collider and of the High-Luminosity LHC, as the luminosity of the collider will significantly exceed the one the machine was originally designed for. To meet the demanding performance requirements of the ATLAS Muon Spectrometer, Micromegas chambers are required to achieve a single plane resolution of $100 \mu m$ with an efficiency better than $95\%$ for tracks up to an inclination of $32 \deg$ in a magnetic field up to $0.3 T$. \\ A thorough test program on Micromegas full size prototypes of the four different types of modules is ongoing, with the goal of well define the assembly methodologies and quality assurance and control of 128 MM modules to be produced and certified for the ATLAS NSW. The tests performed on the first module-0 of SM1 module produced excellent results, proving that the prototype fully meet the performance requirements. \\ The replacement in LS3 of the Inner Detector (ID) by the Inner Tracker (ITk) extends the pseudo-rapidity coverage for tracking up to $|\eta | < 4.0$. As a consequence, it becomes interesting to identify muons in this pseudo-rapidity region. This can be accomplished installing micro-pattern gaseous or silicon pixel detectors between the endcap calorimeters and the shielding disks (JD) in front of the NSW in the region $2.7 < \eta < 4$. These detectors could be used to identify (tag) ITk tracks as muons, relying entirely on the ITk for the momentum measurement. There are currently different proposals for the instrumentation of this region. \\ The ATLAS NSW MM assembly methodologies, the related quality controls and the candidate technologies for the $\eta-$tagger are presented in this document.