Invited Paper VT-TuM9
LHC Beam & Insulation Vacuum Systems

Tuesday, October 21, 2008, 10:40 am, Room 205

In May’08, the world largest vacuum system was fully commissioned and consolidated in the Large Hadron Collider (LHC), a CERN accelerator built near the City of Geneva in Switzerland. Its more than 100 km of vacuum systems are operating over a wide range of pressures and integrates an impressive variety of vacuum technologies. These vacuum systems are composed of 54 km of UHV vacuum for the circulating beams and two times 24 km of insulation vacuum around the cryogenic magnets and for the cryogenic helium transfer lines. 48 km out of the 54 km are operated at a cryogenic temperature (1.9 K). The remaining 6 km of beam vacuum containing the insertions is at ambient temperature and uses non-evaporable getter (NEG) coatings, a vacuum technology that was born and industrialized at CERN. The pumping is completed using 600 ion pumps to remove noble gases; 1000 gauges are used to monitor the pressures. The cryogenic insulation vacuum of the magnets, while technically less demanding, impresses by its 24 km in length and a diameter of 900 mm for a total volume of 640 m3. Once cooled at 1.9 K, the cryogenic pumping allows reaching pressure in the 10-6 mbar range. This talk will introduce the vacuum systems and the challenges of its design, manufacturing, installation, commissioning and consolidation phases.