Studies of MicroMeGas chambers for the new small wheel using cosmic muons

Micromesh Gaseous Detectors (MicroMeGas) will be used in the ATLAS detector for the construction of the New Small Wheel Upgrade during the long shut down II in 2019/20. These detectors are used primarily for accurate position measurement but can also provide additionally trigger information. The spatial resolution is of the order of 100 μm. In parallel to the ongoing constructions of the actual size prototypes, additional performance studies with small MicroMeGas prototypes of a size of 10 × 10 cm2 are performed. These studies include a cosmic muon test setup in combination with a scalable readout system, such that the effect of variations in the pressure of the operation gas or changes in the humidity at the lower ppm level to the detector performance are investigated. These parameters will have an impact on the final design of the slow control system at the New Small Wheel in ATLAS.