ITS Module for the ALICE Experiment

The pictures showcase the mounting of a module of the New Inner Tracking System (ITS) of ALICE, which will be installed in the heart of the experiment in 2020 and will track particles produced in the collisions. The Inner Layers of the ITS are made of 48 of this modules, which are called “staves”, as they are placed as the staves of a barrel, in cylindrical concentric layers around the particle beam line, and centred with respect to the interaction point. Each Inner Layer stave has a sensitive area of about 1.5cm x 27cm, constituted by 9 aligned silicon pixel chip sensors (1.5cm x 3 cm x 50 micron). The sensors are glued on a light carbon fibre support and are connected through a flex printed circuit, which carries both the power supply and the signals. The Inner Layer staves cover a cylindrical volume around the beam line up to a radius of about 4 cm, while 4 additional layers, called Middle and Outer Layers, reach a radius of about 400 cm. The stave of the Middle and Outer Layers are bigger and host 196 chips each.