Construction and operation of large scale Micromegas detectors for the ATLAS Muon upgrade

Abstract After the forthcoming upgrade of the LHC accelerator at CERN, its luminosity will increase up to 7.5 × 1034 cm−2s−1. That will raise the readout rates and the background data to unmanageable levels for the existing ATLAS muon spectrometer. The ATLAS collaboration has proposed to replace the present small wheel muon detector with the New Small Wheel (NSW) to surpass those limitations. The new wheels consist of Micromegas (MM) and small-strip Thin Gap Chambers (sTGC). The first technology aims for precision tracking, and the last one for trigger purposes. Each wheel will be equipped with eight small and eight large sectors, while each sector will have a double MM wedge surrounded by sTGC wedges. The MM detectors for the NSW will be the largest developed Micro Pattern Gaseous Detector (MPGD) as they will cover an area up to 1280 m2. During detectors’ manufacture have been used various custom materials (PCBs, mesh) and innovative construction techniques. This paper describes the MM drift panels production at Aristotle University of Thessaloniki laboratory. Then will be presented resolution results of the MM detectors with cosmic-ray tests at CERN facilities.