Module integration on the inner shells (TIB) of the CMS tracker

The CMS experiment will be installed on the LHC ring. The accelerator will provide pp collisions at the center of mass energy of 14 TeV with a design luminosity of 10
³⁴
cm
^-2
s
^-1
and a bunch crossing frequency of 40 MHz. These characteristics lead to a challenging design of the detectors, in particular of the tracker which will have to cope with ~2000 charged tracks per event and a hadron flux up to 10
¹⁴
cm
^-2
y
^-1
close to the interaction point. Moreover the CMS tracker shall endure 10 years of operation, with little or no chance for maintenance after LHC start-up. It is therefore important not only to verify accurately the quality of the components during the production, but also to monitor step by step the assembly of modules and of the other devices that constitute the final detector. The "integration" procedure used to assemble and test the innermost region of the detector (modules, electronics and services, mechanics...) is described in detail and the noise performances of the modules mounted on the assembled layers is shown.