The assembly of the ALICE silicon pixel detector

The silicon pixel detector (SPD) is the innermost part of the inner tracking system (ITS) of the ALICE experiment at LHC. 240 detector ladders containing in total about 10 million pixel cells with dimension 50/spl middot/425 /spl mu/m/sup 2/, have to be assembled on a carbon fibre support with micrometric precision. The mounting procedure of the basic SPD modules (half-staves) and the assembly of the barrel sectors are presented.