The MRPC detector for the ALICE Time Of Flight System: Final Design and Performances

The ALICE Time Of Flight (TOF) system will perform charged particle identificationin the intermediate momentum range (from 0.5 to a few GeV/c) and in the central pseudorapidityregion ( | η | 0.9 ). In particular the TOF has to cover an area of ∼ 160 m 2 and has to be highly segmented (∼ 160000 readout pads of 2.5 × 3.7 cm 2 active area) in order to keep the occupancy in Pb-Pb collisions below the 15 % level. In order to satisfy these requirements, the double-stack MRPC detector has been chosen for the TOF system. The most relevant results on the performances of the final version of the MRPC and of the front-end/readout electronics will be presented. The device has a very good uniformity, a long streamer-free plateau, an efficiency higher than 99 % and an intrinsic time resolution below 50 ps.