Qweak R1 GEM DNP2009

A tracking system for the Qweak experiment at Jefferson Lab has been constructed using gas electron multipliers (GEMs) to enable the detection of elastically scattered electrons at high rates. Unlike other similar tracking devices, the GEM based tracking system uses a polar coordinate system and custom designed digitization cards for readout. The coordinate system was chosen to simplify a measurement of the elastically scattered electrons squared momentum transfer. A custom readout system was designed at CERN to be used by either silicon or GEM based detection systems. The compact readout system features 128 channels per card. Each channel can be individually controlled. The readout card has a high radiation tolerance. The performance of the readout system will be reported.