Commissioning of the Silicon Drift Detectors of the ALICE experiment at the LHC

Silicon Drift Detectors (SDD) equip the two central layers of the Inner Tracking System of the ALICE experiment at the LHC. Main results of systematic studies of detector performance including noise, gain, drift speed and charge collection measurements will be reported. 1 ALICE experiment and SDD module Silicon Drift Detectors (SDD) [1] offer two-dimensional position reconstruction with a limited number of read-out channels, high granularity and good multi-track detection capability. For these reasons, SDD have been chosen to equip two layers of the ALICE Inner Tracking System, the detector closest to the beam axis [2]. The SDD operating principle [3] is based on the measurement of the time necessary for the electrons produced by the crossing particle to drift, in an adequate electrostatic field, from the generation point to the collecting anodes. The first coordinate (anodic) is obtained from the centroid of the charge distribution along the anodes, while the distance of the crossing point from the anodes (drift coordinate) is determined by the measure of the drift time and requires a precise knowledge of the drift speed.