The ALICE Silicon Pixel Detector: commissioning and performance optimization

This paper describes the tests and measurements made during the final commissioning with beams of the ALICE Silicon Pixel Detector (SPD) in the first year of operation and the optimization of its performance. The ALICE Silicon Pixel Detector (SPD) is the innermost detector of the ALICE experiment and therefore plays a key role for vertexing and tracking. It consists of two cylindrical layers of pixel detectors, with a total of ~ 107 pixels. The detector provides a prompt trigger signal that contributes to the first level trigger decision in ALICE. The trigger signal has been extensively used in the first trigger level of the ALICE experiment for recording data of proton-proton collisions at energies of 900 GeV, 2.36 TeV and 7 TeV