The second generation instrument MUSE (Multi Unit Spectroscopic Explorer) developed for the VLT (Very Large Telescope) for ESO (European Southern Observatory) is composed of 24 identical Integral Field Unit. To perform the tests and the integration in a shorter time, we have developed an opto-mechanical system of AIT Tools (Assembly- Integration-Test) referenced to an unique simulator of IFU. Each IFU sub system and its test bench (sources, image slicer, spectrograph, IFU) are checked with respect to the same opto-mechanical references. These references are also used to align all the 24 IFU onto the MUSE main structure. The system allows a better homogeneity between IFU in term of performances and a better traceability between its sub-systems. This paper presents the different AIT tools developed at CRAL to reach the specified performances for the serial phase of AIT of 24 IFU.
