Test Beam Results with a Full Size sTGC

The forthcoming LHC upgrade to high luminosity will increase the background rate in the forward region of the ATLAS Muon Spectrometer (composed of three Big Wheels (BW) and a Small Wheel (SW) on each side of the detector) by approximately a factor of five. With such a rate some of the present Muon Spectrometer detectors in the SW region will produce fake triggers and will therefore be replaced by a New Small Wheel (NSW) composed of small Thin Gap Chamber (sTGC) and Micromegas planes. The aim of the detectors is to reach 100 micrometers position resolution and an online muon track reconstruction with better than 1 mrad precision. A full size sTGC quadruplet has been constructed and equipped with the first prototype of the dedicated front end electronics (VMM1). The performance of the sTGC quadruplet at the Fermilab test beam facility is presented here.