The barrel sector assembly system of the ALICE silicon pixel detector

The Silicon Pixel Detector is the inner part of the ITS tracking system of the ALICE experiment at LHC. The 240 silicon modules, hosting almost 10 million pixel cells with dimension 50 /spl middot/ 425 /spl mu/m/sup 2/, have to be assembled on a carbon fiber support with micrometric precision. To reach this result, a dedicated high-precision computer-controlled tooling system has been developed at the INFN Padova. The assembly system and the mounting procedures are presented.