Assembly and commissioning of the LHC test string

The assembly of the first version of the LHC test string has now been completed and commissioned. It makes use of the prototype short straight section assembled at CERN with its quadrupole and of the first two 10 m long dipoles manufactured by industry. The LHC string will be used to study phenomena which can be observed only when the different components are assembled in a prototype LHC cell, and will be completed with two other dipole magnets, as soon as they become available. This paper describes the major components present in the LHC string and the issues related to its mechanical assembly. It also reports on the different stages of the commissioning of the cryogenic equipment, the powering and the quench protection systems, together with their associated industrial controls and the data acquisition system. Longer term evolution of the string configuration is finally described.