Status and performance of the ALICE Silicon Drift Detector in pp and Pb-Pb collisions

摘要

The ALICE Silicon Drift Detector (SDD) equips the two intermediate layers of the Inner Tracking System (ITS), which is operated at the Large Hadron Collider (LHC) at CERN. The SDD shows very good multi-track capability and provides two out of the four dEjdx samples used for particle identification with the ITS. The detector consists of 260 large area silicon sensors featuring approximately 133 k electronic channels. This paper presents the status and performance of the SDD during the data taking of 2011/12. During this period the system was smoothly operated with very high operational efficiency. The hardware status of drift detectors, front-end electronics and readout boards will be described, focusing in particular on detector operation and on-line monitoring during the data taking period. The calibration strategy for what concerns the periodical measurement of the drift velocity using MOS charge injectors will also be discussed, since a precise knowledge of the drift velocity is crucial to reach high space resolution on the reconstructed hits with the SDD.