Mainz-based working group constructed a prototype detector for the Small Wheel of the ATLAS muon spectrometer / Results of initial tests on the ATLAS detector are highly promising. One of the largest projects being undertaken at the CERN research center near Geneva – the ATLAS Experiment – is about to be upgraded. ATLAS played a crucial role in the discovery of the Higgs boson in 2012. With a length of 46 meters and a diameter of 25 meters the ATLAS detector is thus the largest device of its kind being used at a particle accelerator. It is planned to upgrade the ATLAS detector from late 2018 onwards. Researchers at Johannes Gutenberg University Mainz (JGU) and CERN have developed an initial prototype for this endeavor, which has now been installed at the ATLAS detector.