System Test and Noise Performance Studies at The ATLAS Pixel Detector

The central component of the ATLAS Inner Tracker is the pixel detector. It consists of three barrel layers and three disk-layers in the endcaps in both forward directions. The innermost barrel layer is mounted at a distance of about 5~cm from the interaction region. With its very high granularity, truly two-dimensional hit information, and fast readout it is well suited to cope with the high densities of charged tracks, expected this close to the interaction region. The huge number of readout channels necessitates a very complex services infrastructure for powering, readout and safety. After a description of the pixel detector and its services infrastructure, key results from the system test at CERN are presented. Furthermore the noise performance of the pixel detector, crucial for high tracking and vertexing efficiencies, is studied. Measurements of the single-channel random noise are presented together with studies of common mode noise and measurements of the noise occupancy using a random trigger generator.