Performance Studies of Micromegas Chambers for the New Small Wheel Upgrade Project

The ATLAS collaboration has chosen the Micromegas technology along with the small-strip Thin Gap Chambers for the upgrade of the inner muon station in the high-rapidity region, the so called New Small Wheel upgrade project. It will employ eight layers of Micromegas and eight layers of small-strip Thin Gap Chambers per wheel. The New Small Wheel project requires fully efficient Micromegas chambers, able to cope with the maximum expected rate of 15 kHz/cm2 featuring single plane spatial resolution better than 100 μm. The Micromegas detectors will cover a total active area of ~ 1200 m2 and will be operated in a moderate magnetic field (≤ 0.3 T). Moreover, together with their precise tracking capability the New Small Wheel Micromegas chambers will contribute to the ATLAS Level-1 trigger system. Several studies have been performed on small (10 × 10 cm2) and medium (1 × 0.5 m2) size prototypes using medium (1 − 5 GeV/c) and high momentum (120 – 150 GeV/c) hadron beams at CERN. A brief overview of the results obtained is presented