The ALICE Inner Tracking System : present and future

by Annalisa Mastroserio (Universita degli Studi di Bari)

Friday 2 Dec 2011, 11:00 → 12:00 Europe/Zurich

222/R-001 (CERN)

The ALICE Inner Tracking System (ITS) is constituted by six layers of silicon detectors arranged in a barrel geometry. It is the closest detector to the beam pipe and its role is to contribute to vertexing and tracking in combination with the TPC in the very high track density environment of central PbPb collisions. The low momentum particles, which do not reach the TPC, are reconstructed by the ITS standalone. The ITS provides also particle identification in the non-relativistic region. The detector makes use of three different silicon detector technologies: the two innermost layers consist of Silicon Pixel Detectors (SPD), the two intermediate layers contain Silicon Drift Detectors (SDD) whereas the two outermost layers are equipped with Silicon Strip Detectors (SSD). Among the silicon tracker of the LHC experiment the ITS has also the unique feature of providing a fast signal that can contribute to the L0 trigger decision with excellent results. In this seminar, the performance of the current ITS with p-p and PbPb collisions will be presented. The studies for an upgade of the ITS have progressively increased in the last year with the aim to enhance the ALICE physics capabilities and in particular the tracking performance for heavy-flavour detection. The requirements of a new silicon tracker to measure charm and beauty production in PbPb collisions down to very low transverse momenta and sufficient statistical accuracy are being addressed with dedicated simulations. An intensive R&D program has been launched with the objective to build a new detector ready to be installed during the long LHC shutdown period scheduled in 2017-2018. Preliminary results on the foreseen physics performances of a new ALICE ITS will be discussed.