Title: Upgrade of the ALICE Inner Tracking System
Abstract: ALICE (A Large Ion Collider Experiment) is designed to study the physics of strongly interacting matter, and in particular the properties of the Quark-Gluon Plasma (QGP), using proton-proton, proton-nucleus and nucleus-nucleus collisions at the CERN LHC (Large Hadron Collider). As a major part of its upgrade plan, the ALICE experiment schedules installation of a new, ultra-light, high-resolution Inner Tracking System (ITS) during the long LHC shutdown in 2018-2019. The new ITS will improve the ALICE performance of detection of heavy-flavor hadrons, and of thermal photons and low-mass di-electrons emitted by the QGP. The new ITS will replace the current silicon tracker with seven layers of Monolithic Active Pixel Sensors (MAPS) and will significantly enhance the detector performance in terms of the determination of the distance of closest approach to the primary vertex, the tracking efficiency at low transverse momenta and the read-out rate capabilities. A key feature of the new ITS, which is optimized for high tracking accuracy at low transverse momenta, is the very low mass of the three innermost layers, which feature a material thickness of 0.3% X0 per layer. This talk presents the design goals and layout of the new ALICE ITS, status of R&D activities, and the projected detector and physics performance.
HEP April21 flyer