The quench protection system for the LHC test string 2

The large hadron collider (LHC) string program has focused over the years the efforts of many teams that have tested and validated their systems under operating conditions close to the final ones in the LHC machine tunnel and underground areas. During the various phases while commissioning or performing dedicated experiments, the quench protection system (QPS) has been tested and improved. A large variety of designs of the QPS equipment have been validated. The experience gained, especially concerning both the commissioning and the interaction with systems working within close interfaces (interlocks, powering, controls), is a valuable expertise to undertake the LHC challenge. In the LHC, the QPS will be the only system monitoring and protecting the superconducting elements: the integrity of all the superconducting magnets, bus bars and high-T_c superconducting current leads will depend on its reliable operation. A description of the system installed in String 2 will be given together with the principal similarities and differences with respect to the equipment planned for installation in the LHC. The key experimental results will be explained.