The industrial production and validation of Micromegas boards for the ATLAS upgrade

The muon system of the ATLAS Experiment is currently undergoing a major upgrade, with the replacement of the innermost detector wheel with new structures (New Small Wheel, NSW) based on resistive Micromegas and small-strip Thin Gap Chambers. The Micromegas detectors for the New Small Wheel cover an active area of about 1280 m2, being the largest system based on Micro Pattern Gaseous Detector (MPGD) ever built so far. The key element of the detectors are the anode boards which carry the readout strips, the resistive protection layer and the insulating pillars supporting the mesh. In total more about 3000 boards of 16 different types with size up to 40x220 cm2 have been produced. The boards, of 16 different types with size up to 40x220 cm2, are produced by two industries in Europe, which opened the road to MPGD mass production. The industrial production of about 3000 boards is now completed. Each board undergoes a detailed quality control and quality assurance at CERN, prior to be mounted into the final detectors. The talk will review the technological transfer effort made by CERN and ATLAS to make the Micromegas board production an industrial process. The main challenges encountered during the industrialisation and the adopted solutions will be presented in detail, together with the results of the QA/QC performed at CERN.