Characterization of the pixel module for the ALICE ITS upgrade

Abstract

The ALICE Collaboration is preparing a major upgrade of the experimental apparatus, planned for installation in the second long LHC shutdown m the years 2019–2020. The key element of the ALICE upgrade is the construction of the new high resolution Inner Tracking System (ITS). It will be made of seven concentric detector layers based on a 50μm thick CMOS pixel sensor with a pixel pitch of 30 × 30 μm2 called ALPIDE. The upgraded ITS will be realized using more than twenty-four thousand ALPIDE chips organized in seven different cylindrical layers (called Inner and Outer layers) covering a total surface of about ten square meters. The main features of the new ITS are a low material budget, high granularity and low power consumption. The Hybrid Integrated Circuit (HIC) module is the building element of the four Outer Layers of the upgraded ITS and it is realized assembling together fourteen Monolithic Active Silicon Pixel Sensors with a space precision of the order of few microns. In this paper, after a brief overview of the ITS upgrade project, the construction procedure, the electrical characterization and the qualification tests on the Outer Barrel modules are presented.